8172190: Re-apply the fix for bugs 8062389, 8029459, 8061950

Final fix for 8062389: Class.getMethod() is inconsistent with Class.getMethods() results, 8029459: getMethods returns methods that are not members of the class, 8061950: Class.getMethods() exhibits quadratic time complexity

Reviewed-by: alanb, mchung, psandoz, dfuchs, darcy, redestad

jdk/src/java.base/share/classes/java/lang/Class.java

@@ -26,8 +26,6 @@
 package java.lang;
 
 import java.lang.annotation.Annotation;
-import java.lang.module.ModuleDescriptor.Version;
-import java.lang.module.ModuleFinder;
 import java.lang.module.ModuleReader;
 import java.lang.ref.SoftReference;
 import java.io.IOException;
@@ -42,7 +40,6 @@ import java.lang.reflect.Field;
 import java.lang.reflect.GenericArrayType;
 import java.lang.reflect.GenericDeclaration;
 import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Layer;
 import java.lang.reflect.Member;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
@@ -54,7 +51,6 @@ import java.net.URL;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -62,19 +58,15 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.Optional;
 import java.util.Set;
 import java.util.StringJoiner;
-import java.util.stream.Collectors;
 
 import jdk.internal.HotSpotIntrinsicCandidate;
 import jdk.internal.loader.BootLoader;
 import jdk.internal.loader.BuiltinClassLoader;
 import jdk.internal.loader.ResourceHelper;
-import jdk.internal.misc.SharedSecrets;
 import jdk.internal.misc.Unsafe;
 import jdk.internal.misc.VM;
-import jdk.internal.module.ModuleHashes;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.ConstantPool;
 import jdk.internal.reflect.Reflection;
@@ -532,7 +524,8 @@ public final class Class<T> implements java.io.Serializable,
             }
             try {
                 Class<?>[] empty = {};
-                final Constructor<T> c = getConstructor0(empty, Member.DECLARED);
+                final Constructor<T> c = getReflectionFactory().copyConstructor(
+                    getConstructor0(empty, Member.DECLARED));
                 // Disable accessibility checks on the constructor
                 // since we have to do the security check here anyway
                 // (the stack depth is wrong for the Constructor's
@@ -1024,6 +1017,11 @@ public final class Class<T> implements java.io.Serializable,
      * @return an array of interfaces directly implemented by this class
      */
     public Class<?>[] getInterfaces() {
+        // defensively copy before handing over to user code
+        return getInterfaces(true);
+    }
+
+    private Class<?>[] getInterfaces(boolean cloneArray) {
         ReflectionData<T> rd = reflectionData();
         if (rd == null) {
             // no cloning required
@@ -1034,8 +1032,8 @@ public final class Class<T> implements java.io.Serializable,
                 interfaces = getInterfaces0();
                 rd.interfaces = interfaces;
             }
-            // defensively copy before handing over to user code
+            // defensively copy if requested
-            return interfaces.clone();
+            return cloneArray ? interfaces.clone() : interfaces;
         }
     }
 
@@ -1767,15 +1765,6 @@ public final class Class<T> implements java.io.Serializable,
      * Class} object, including those declared by the class or interface and
      * those inherited from superclasses and superinterfaces.
      *
-     * <p> If this {@code Class} object represents a type that has multiple
-     * public methods with the same name and parameter types, but different
-     * return types, then the returned array has a {@code Method} object for
-     * each such method.
-     *
-     * <p> If this {@code Class} object represents a type with a class
-     * initialization method {@code <clinit>}, then the returned array does
-     * <em>not</em> have a corresponding {@code Method} object.
-     *
      * <p> If this {@code Class} object represents an array type, then the
      * returned array has a {@code Method} object for each of the public
      * methods inherited by the array type from {@code Object}. It does not
@@ -1788,16 +1777,54 @@ public final class Class<T> implements java.io.Serializable,
      * has length 0. (Note that a {@code Class} object which represents a class
      * always has public methods, inherited from {@code Object}.)
      *
-     * <p> If this {@code Class} object represents a primitive type or void,
+     * <p> The returned array never contains methods with names "{@code <init>}"
-     * then the returned array has length 0.
+     * or "{@code <clinit>}".
-     *
-     * <p> Static methods declared in superinterfaces of the class or interface
-     * represented by this {@code Class} object are not considered members of
-     * the class or interface.
      *
      * <p> The elements in the returned array are not sorted and are not in any
      * particular order.
      *
+     * <p> Generally, the result is computed as with the following 4 step algorithm.
+     * Let C be the class or interface represented by this {@code Class} object:
+     * <ol>
+     * <li> A union of methods is composed of:
+     *   <ol type="a">
+     *   <li> C's declared public instance and static methods as returned by
+     *        {@link #getDeclaredMethods()} and filtered to include only public
+     *        methods.</li>
+     *   <li> If C is a class other than {@code Object}, then include the result
+     *        of invoking this algorithm recursively on the superclass of C.</li>
+     *   <li> Include the results of invoking this algorithm recursively on all
+     *        direct superinterfaces of C, but include only instance methods.</li>
+     *   </ol></li>
+     * <li> Union from step 1 is partitioned into subsets of methods with same
+     *      signature (name, parameter types) and return type.</li>
+     * <li> Within each such subset only the most specific methods are selected.
+     *      Let method M be a method from a set of methods with same signature
+     *      and return type. M is most specific if there is no such method
+     *      N != M from the same set, such that N is more specific than M.
+     *      N is more specific than M if:
+     *   <ol type="a">
+     *   <li> N is declared by a class and M is declared by an interface; or</li>
+     *   <li> N and M are both declared by classes or both by interfaces and
+     *        N's declaring type is the same as or a subtype of M's declaring type
+     *        (clearly, if M's and N's declaring types are the same type, then
+     *        M and N are the same method).</li>
+     *   </ol></li>
+     * <li> The result of this algorithm is the union of all selected methods from
+     *      step 3.</li>
+     * </ol>
+     *
+     * @apiNote There may be more than one method with a particular name
+     * and parameter types in a class because while the Java language forbids a
+     * class to declare multiple methods with the same signature but different
+     * return types, the Java virtual machine does not.  This
+     * increased flexibility in the virtual machine can be used to
+     * implement various language features.  For example, covariant
+     * returns can be implemented with {@linkplain
+     * java.lang.reflect.Method#isBridge bridge methods}; the bridge
+     * method and the overriding method would have the same
+     * signature but different return types.
+     *
      * @return the array of {@code Method} objects representing the
      *         public methods of this class
      * @throws SecurityException
@@ -1900,12 +1927,13 @@ public final class Class<T> implements java.io.Serializable,
     @CallerSensitive
     public Field getField(String name)
         throws NoSuchFieldException, SecurityException {
+        Objects.requireNonNull(name);
         checkMemberAccess(Member.PUBLIC, Reflection.getCallerClass(), true);
         Field field = getField0(name);
         if (field == null) {
             throw new NoSuchFieldException(name);
         }
-        return field;
+        return getReflectionFactory().copyField(field);
     }
 
 
@@ -1919,47 +1947,69 @@ public final class Class<T> implements java.io.Serializable,
      * order. If {@code parameterTypes} is {@code null}, it is
      * treated as if it were an empty array.
      *
-     * <p> If the {@code name} is "{@code <init>}" or "{@code <clinit>}" a
+     * <p> If this {@code Class} object represents an array type, then this
-     * {@code NoSuchMethodException} is raised. Otherwise, the method to
+     * method finds any public method inherited by the array type from
-     * be reflected is determined by the algorithm that follows.  Let C be the
+     * {@code Object} except method {@code clone()}.
-     * class or interface represented by this object:
-     * <OL>
-     * <LI> C is searched for a <I>matching method</I>, as defined below. If a
-     *      matching method is found, it is reflected.</LI>
-     * <LI> If no matching method is found by step 1 then:
-     *   <OL TYPE="a">
-     *   <LI> If C is a class other than {@code Object}, then this algorithm is
-     *        invoked recursively on the superclass of C.</LI>
-     *   <LI> If C is the class {@code Object}, or if C is an interface, then
-     *        the superinterfaces of C (if any) are searched for a matching
-     *        method. If any such method is found, it is reflected.</LI>
-     *   </OL></LI>
-     * </OL>
      *
-     * <p> To find a matching method in a class or interface C:&nbsp; If C
+     * <p> If this {@code Class} object represents an interface then this
-     * declares exactly one public method with the specified name and exactly
+     * method does not find any implicitly declared method from
-     * the same formal parameter types, that is the method reflected. If more
+     * {@code Object}. Therefore, if no methods are explicitly declared in
-     * than one such method is found in C, and one of these methods has a
+     * this interface or any of its superinterfaces, then this method does not
-     * return type that is more specific than any of the others, that method is
+     * find any method.
-     * reflected; otherwise one of the methods is chosen arbitrarily.
      *
-     * <p>Note that there may be more than one matching method in a
+     * <p> This method does not find any method with name "{@code <init>}" or
-     * class because while the Java language forbids a class to
+     * "{@code <clinit>}".
-     * declare multiple methods with the same signature but different
+     *
+     * <p> Generally, the method to be reflected is determined by the 4 step
+     * algorithm that follows.
+     * Let C be the class or interface represented by this {@code Class} object:
+     * <ol>
+     * <li> A union of methods is composed of:
+     *   <ol type="a">
+     *   <li> C's declared public instance and static methods as returned by
+     *        {@link #getDeclaredMethods()} and filtered to include only public
+     *        methods that match given {@code name} and {@code parameterTypes}</li>
+     *   <li> If C is a class other than {@code Object}, then include the result
+     *        of invoking this algorithm recursively on the superclass of C.</li>
+     *   <li> Include the results of invoking this algorithm recursively on all
+     *        direct superinterfaces of C, but include only instance methods.</li>
+     *   </ol></li>
+     * <li> This union is partitioned into subsets of methods with same
+     *      return type (the selection of methods from step 1 also guarantees that
+     *      they have the same method name and parameter types).</li>
+     * <li> Within each such subset only the most specific methods are selected.
+     *      Let method M be a method from a set of methods with same VM
+     *      signature (return type, name, parameter types).
+     *      M is most specific if there is no such method N != M from the same
+     *      set, such that N is more specific than M. N is more specific than M
+     *      if:
+     *   <ol type="a">
+     *   <li> N is declared by a class and M is declared by an interface; or</li>
+     *   <li> N and M are both declared by classes or both by interfaces and
+     *        N's declaring type is the same as or a subtype of M's declaring type
+     *        (clearly, if M's and N's declaring types are the same type, then
+     *        M and N are the same method).</li>
+     *   </ol></li>
+     * <li> The result of this algorithm is chosen arbitrarily from the methods
+     *      with most specific return type among all selected methods from step 3.
+     *      Let R be a return type of a method M from the set of all selected methods
+     *      from step 3. M is a method with most specific return type if there is
+     *      no such method N != M from the same set, having return type S != R,
+     *      such that S is a subtype of R as determined by
+     *      R.class.{@link #isAssignableFrom}(S.class).
+     * </ol>
+     *
+     * @apiNote There may be more than one method with matching name and
+     * parameter types in a class because while the Java language forbids a
+     * class to declare multiple methods with the same signature but different
      * return types, the Java virtual machine does not.  This
      * increased flexibility in the virtual machine can be used to
      * implement various language features.  For example, covariant
      * returns can be implemented with {@linkplain
      * java.lang.reflect.Method#isBridge bridge methods}; the bridge
-     * method and the method being overridden would have the same
+     * method and the overriding method would have the same
-     * signature but different return types.
+     * signature but different return types. This method would return the
-     *
+     * overriding method as it would have a more specific return type.
-     * <p> If this {@code Class} object represents an array type, then this
-     * method does not find the {@code clone()} method.
-     *
-     * <p> Static methods declared in superinterfaces of the class or interface
-     * represented by this {@code Class} object are not considered members of
-     * the class or interface.
      *
      * @param name the name of the method
      * @param parameterTypes the list of parameters
@@ -1983,12 +2033,13 @@ public final class Class<T> implements java.io.Serializable,
     @CallerSensitive
     public Method getMethod(String name, Class<?>... parameterTypes)
         throws NoSuchMethodException, SecurityException {
+        Objects.requireNonNull(name);
         checkMemberAccess(Member.PUBLIC, Reflection.getCallerClass(), true);
-        Method method = getMethod0(name, parameterTypes, true);
+        Method method = getMethod0(name, parameterTypes);
         if (method == null) {
             throw new NoSuchMethodException(getName() + "." + name + argumentTypesToString(parameterTypes));
         }
-        return method;
+        return getReflectionFactory().copyMethod(method);
     }
 
     /**
@@ -2004,7 +2055,9 @@ public final class Class<T> implements java.io.Serializable,
      *         "&lt;init&gt;"or "&lt;clinit&gt;".
      */
     Method getMethodOrNull(String name, Class<?>... parameterTypes) {
-        return getMethod0(name, parameterTypes, true);
+        Objects.requireNonNull(name);
+        Method method = getMethod0(name, parameterTypes);
+        return method == null ? null : getReflectionFactory().copyMethod(method);
     }
 
 
@@ -2041,7 +2094,8 @@ public final class Class<T> implements java.io.Serializable,
     public Constructor<T> getConstructor(Class<?>... parameterTypes)
         throws NoSuchMethodException, SecurityException {
         checkMemberAccess(Member.PUBLIC, Reflection.getCallerClass(), true);
-        return getConstructor0(parameterTypes, Member.PUBLIC);
+        return getReflectionFactory().copyConstructor(
+            getConstructor0(parameterTypes, Member.PUBLIC));
     }
 
 
@@ -2283,12 +2337,13 @@ public final class Class<T> implements java.io.Serializable,
     @CallerSensitive
     public Field getDeclaredField(String name)
         throws NoSuchFieldException, SecurityException {
+        Objects.requireNonNull(name);
         checkMemberAccess(Member.DECLARED, Reflection.getCallerClass(), true);
         Field field = searchFields(privateGetDeclaredFields(false), name);
         if (field == null) {
             throw new NoSuchFieldException(name);
         }
-        return field;
+        return getReflectionFactory().copyField(field);
     }
 
 
@@ -2343,12 +2398,13 @@ public final class Class<T> implements java.io.Serializable,
     @CallerSensitive
     public Method getDeclaredMethod(String name, Class<?>... parameterTypes)
         throws NoSuchMethodException, SecurityException {
+        Objects.requireNonNull(name);
         checkMemberAccess(Member.DECLARED, Reflection.getCallerClass(), true);
         Method method = searchMethods(privateGetDeclaredMethods(false), name, parameterTypes);
         if (method == null) {
             throw new NoSuchMethodException(getName() + "." + name + argumentTypesToString(parameterTypes));
         }
-        return method;
+        return getReflectionFactory().copyMethod(method);
     }
 
 
@@ -2394,7 +2450,8 @@ public final class Class<T> implements java.io.Serializable,
     public Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes)
         throws NoSuchMethodException, SecurityException {
         checkMemberAccess(Member.DECLARED, Reflection.getCallerClass(), true);
-        return getConstructor0(parameterTypes, Member.DECLARED);
+        return getReflectionFactory().copyConstructor(
+            getConstructor0(parameterTypes, Member.DECLARED));
     }
 
     /**
@@ -3004,180 +3061,6 @@ public final class Class<T> implements java.io.Serializable,
         return res;
     }
 
-    static class MethodArray {
-        // Don't add or remove methods except by add() or remove() calls.
-        private Method[] methods;
-        private int length;
-        private int defaults;
-
-        MethodArray() {
-            this(20);
-        }
-
-        MethodArray(int initialSize) {
-            if (initialSize < 2)
-                throw new IllegalArgumentException("Size should be 2 or more");
-
-            methods = new Method[initialSize];
-            length = 0;
-            defaults = 0;
-        }
-
-        boolean hasDefaults() {
-            return defaults != 0;
-        }
-
-        void add(Method m) {
-            if (length == methods.length) {
-                methods = Arrays.copyOf(methods, 2 * methods.length);
-            }
-            methods[length++] = m;
-
-            if (m != null && m.isDefault())
-                defaults++;
-        }
-
-        void addAll(Method[] ma) {
-            for (Method m : ma) {
-                add(m);
-            }
-        }
-
-        void addAll(MethodArray ma) {
-            for (int i = 0; i < ma.length(); i++) {
-                add(ma.get(i));
-            }
-        }
-
-        void addIfNotPresent(Method newMethod) {
-            for (int i = 0; i < length; i++) {
-                Method m = methods[i];
-                if (m == newMethod || (m != null && m.equals(newMethod))) {
-                    return;
-                }
-            }
-            add(newMethod);
-        }
-
-        void addAllIfNotPresent(MethodArray newMethods) {
-            for (int i = 0; i < newMethods.length(); i++) {
-                Method m = newMethods.get(i);
-                if (m != null) {
-                    addIfNotPresent(m);
-                }
-            }
-        }
-
-        /* Add Methods declared in an interface to this MethodArray.
-         * Static methods declared in interfaces are not inherited.
-         */
-        void addInterfaceMethods(Method[] methods) {
-            for (Method candidate : methods) {
-                if (!Modifier.isStatic(candidate.getModifiers())) {
-                    add(candidate);
-                }
-            }
-        }
-
-        int length() {
-            return length;
-        }
-
-        Method get(int i) {
-            return methods[i];
-        }
-
-        Method getFirst() {
-            for (Method m : methods)
-                if (m != null)
-                    return m;
-            return null;
-        }
-
-        void removeByNameAndDescriptor(Method toRemove) {
-            for (int i = 0; i < length; i++) {
-                Method m = methods[i];
-                if (m != null && matchesNameAndDescriptor(m, toRemove)) {
-                    remove(i);
-                }
-            }
-        }
-
-        private void remove(int i) {
-            if (methods[i] != null && methods[i].isDefault())
-                defaults--;
-                    methods[i] = null;
-                }
-
-        private boolean matchesNameAndDescriptor(Method m1, Method m2) {
-            return m1.getReturnType() == m2.getReturnType() &&
-                   m1.getName() == m2.getName() && // name is guaranteed to be interned
-                   arrayContentsEq(m1.getParameterTypes(),
-                           m2.getParameterTypes());
-            }
-
-        void compactAndTrim() {
-            int newPos = 0;
-            // Get rid of null slots
-            for (int pos = 0; pos < length; pos++) {
-                Method m = methods[pos];
-                if (m != null) {
-                    if (pos != newPos) {
-                        methods[newPos] = m;
-                    }
-                    newPos++;
-                }
-            }
-            if (newPos != methods.length) {
-                methods = Arrays.copyOf(methods, newPos);
-            }
-        }
-
-        /* Removes all Methods from this MethodArray that have a more specific
-         * default Method in this MethodArray.
-         *
-         * Users of MethodArray are responsible for pruning Methods that have
-         * a more specific <em>concrete</em> Method.
-         */
-        void removeLessSpecifics() {
-            if (!hasDefaults())
-                return;
-
-            for (int i = 0; i < length; i++) {
-                Method m = get(i);
-                if  (m == null || !m.isDefault())
-                    continue;
-
-                for (int j  = 0; j < length; j++) {
-                    if (i == j)
-                        continue;
-
-                    Method candidate = get(j);
-                    if (candidate == null)
-                        continue;
-
-                    if (!matchesNameAndDescriptor(m, candidate))
-                        continue;
-
-                    if (hasMoreSpecificClass(m, candidate))
-                        remove(j);
-                }
-            }
-        }
-
-        Method[] getArray() {
-            return methods;
-        }
-
-        // Returns true if m1 is more specific than m2
-        static boolean hasMoreSpecificClass(Method m1, Method m2) {
-            Class<?> m1Class = m1.getDeclaringClass();
-            Class<?> m2Class = m2.getDeclaringClass();
-            return m1Class != m2Class && m2Class.isAssignableFrom(m1Class);
-        }
-    }
-
-
     // Returns an array of "root" methods. These Method objects must NOT
     // be propagated to the outside world, but must instead be copied
     // via ReflectionFactory.copyMethod.
@@ -3190,51 +3073,29 @@ public final class Class<T> implements java.io.Serializable,
         }
 
         // No cached value available; compute value recursively.
-        // Start by fetching public declared methods
+        // Start by fetching public declared methods...
-        MethodArray methods = new MethodArray();
+        PublicMethods pms = new PublicMethods();
-        {
+        for (Method m : privateGetDeclaredMethods(/* publicOnly */ true)) {
-            Method[] tmp = privateGetDeclaredMethods(true);
+            pms.merge(m);
-            methods.addAll(tmp);
         }
-        // Now recur over superclass and direct superinterfaces.
+        // ...then recur over superclass methods...
-        // Go over superinterfaces first so we can more easily filter
+        Class<?> sc = getSuperclass();
-        // out concrete implementations inherited from superclasses at
+        if (sc != null) {
-        // the end.
+            for (Method m : sc.privateGetPublicMethods()) {
-        MethodArray inheritedMethods = new MethodArray();
+                pms.merge(m);
-        for (Class<?> i : getInterfaces()) {
-            inheritedMethods.addInterfaceMethods(i.privateGetPublicMethods());
-        }
-        if (!isInterface()) {
-            Class<?> c = getSuperclass();
-            if (c != null) {
-                MethodArray supers = new MethodArray();
-                supers.addAll(c.privateGetPublicMethods());
-                // Filter out concrete implementations of any
-                // interface methods
-                for (int i = 0; i < supers.length(); i++) {
-                    Method m = supers.get(i);
-                    if (m != null &&
-                            !Modifier.isAbstract(m.getModifiers()) &&
-                            !m.isDefault()) {
-                        inheritedMethods.removeByNameAndDescriptor(m);
-                    }
-                }
-                // Insert superclass's inherited methods before
-                // superinterfaces' to satisfy getMethod's search
-                // order
-                supers.addAll(inheritedMethods);
-                inheritedMethods = supers;
             }
         }
-        // Filter out all local methods from inherited ones
+        // ...and finally over direct superinterfaces.
-        for (int i = 0; i < methods.length(); i++) {
+        for (Class<?> intf : getInterfaces(/* cloneArray */ false)) {
-            Method m = methods.get(i);
+            for (Method m : intf.privateGetPublicMethods()) {
-            inheritedMethods.removeByNameAndDescriptor(m);
+                // static interface methods are not inherited
+                if (!Modifier.isStatic(m.getModifiers())) {
+                    pms.merge(m);
+                }
+            }
         }
-        methods.addAllIfNotPresent(inheritedMethods);
+
-        methods.removeLessSpecifics();
+        res = pms.toArray();
-        methods.compactAndTrim();
-        res = methods.getArray();
         if (rd != null) {
             rd.publicMethods = res;
         }
@@ -3246,17 +3107,20 @@ public final class Class<T> implements java.io.Serializable,
     // Helpers for fetchers of one field, method, or constructor
     //
 
+    // This method does not copy the returned Field object!
     private static Field searchFields(Field[] fields, String name) {
-        String internedName = name.intern();
         for (Field field : fields) {
-            if (field.getName() == internedName) {
+            if (field.getName().equals(name)) {
-                return getReflectionFactory().copyField(field);
+                return field;
             }
         }
         return null;
     }
 
-    private Field getField0(String name) throws NoSuchFieldException {
+    // Returns a "root" Field object. This Field object must NOT
+    // be propagated to the outside world, but must instead be copied
+    // via ReflectionFactory.copyField.
+    private Field getField0(String name) {
         // Note: the intent is that the search algorithm this routine
         // uses be equivalent to the ordering imposed by
         // privateGetPublicFields(). It fetches only the declared
@@ -3270,7 +3134,7 @@ public final class Class<T> implements java.io.Serializable,
             return res;
         }
         // Direct superinterfaces, recursively
-        Class<?>[] interfaces = getInterfaces();
+        Class<?>[] interfaces = getInterfaces(/* cloneArray */ false);
         for (Class<?> c : interfaces) {
             if ((res = c.getField0(name)) != null) {
                 return res;
@@ -3288,87 +3152,85 @@ public final class Class<T> implements java.io.Serializable,
         return null;
     }
 
+    // This method does not copy the returned Method object!
     private static Method searchMethods(Method[] methods,
                                         String name,
                                         Class<?>[] parameterTypes)
     {
+        ReflectionFactory fact = getReflectionFactory();
         Method res = null;
-        String internedName = name.intern();
         for (Method m : methods) {
-            if (m.getName() == internedName
+            if (m.getName().equals(name)
-                && arrayContentsEq(parameterTypes, m.getParameterTypes())
+                && arrayContentsEq(parameterTypes,
+                                   fact.getExecutableSharedParameterTypes(m))
                 && (res == null
-                    || res.getReturnType().isAssignableFrom(m.getReturnType())))
+                    || (res.getReturnType() != m.getReturnType()
+                        && res.getReturnType().isAssignableFrom(m.getReturnType()))))
                 res = m;
         }
-
+        return res;
-        return (res == null ? res : getReflectionFactory().copyMethod(res));
     }
 
-    private Method getMethod0(String name, Class<?>[] parameterTypes, boolean includeStaticMethods) {
+    private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
-        MethodArray interfaceCandidates = new MethodArray(2);
+
-        Method res =  privateGetMethodRecursive(name, parameterTypes, includeStaticMethods, interfaceCandidates);
+    // Returns a "root" Method object. This Method object must NOT
-        if (res != null)
+    // be propagated to the outside world, but must instead be copied
+    // via ReflectionFactory.copyMethod.
+    private Method getMethod0(String name, Class<?>[] parameterTypes) {
+        PublicMethods.MethodList res = getMethodsRecursive(
+            name,
+            parameterTypes == null ? EMPTY_CLASS_ARRAY : parameterTypes,
+            /* includeStatic */ true);
+        return res == null ? null : res.getMostSpecific();
+    }
+
+    // Returns a list of "root" Method objects. These Method objects must NOT
+    // be propagated to the outside world, but must instead be copied
+    // via ReflectionFactory.copyMethod.
+    private PublicMethods.MethodList getMethodsRecursive(String name,
+                                                         Class<?>[] parameterTypes,
+                                                         boolean includeStatic) {
+        // 1st check declared public methods
+        Method[] methods = privateGetDeclaredMethods(/* publicOnly */ true);
+        PublicMethods.MethodList res = PublicMethods.MethodList
+            .filter(methods, name, parameterTypes, includeStatic);
+        // if there is at least one match among declared methods, we need not
+        // search any further as such match surely overrides matching methods
+        // declared in superclass(es) or interface(s).
+        if (res != null) {
             return res;
+        }
 
-        // Not found on class or superclass directly
+        // if there was no match among declared methods,
-        interfaceCandidates.removeLessSpecifics();
+        // we must consult the superclass (if any) recursively...
-        return interfaceCandidates.getFirst(); // may be null
+        Class<?> sc = getSuperclass();
-    }
+        if (sc != null) {
-
+            res = sc.getMethodsRecursive(name, parameterTypes, includeStatic);
-    private Method privateGetMethodRecursive(String name,
+        }
-            Class<?>[] parameterTypes,
+
-            boolean includeStaticMethods,
+        // ...and coalesce the superclass methods with methods obtained
-            MethodArray allInterfaceCandidates) {
+        // from directly implemented interfaces excluding static methods...
-        // Note: the intent is that the search algorithm this routine
+        for (Class<?> intf : getInterfaces(/* cloneArray */ false)) {
-        // uses be equivalent to the ordering imposed by
+            res = PublicMethods.MethodList.merge(
-        // privateGetPublicMethods(). It fetches only the declared
+                res, intf.getMethodsRecursive(name, parameterTypes,
-        // public methods for each class, however, to reduce the
+                                              /* includeStatic */ false));
-        // number of Method objects which have to be created for the
+        }
-        // common case where the method being requested is declared in
+
-        // the class which is being queried.
+        return res;
-        //
-        // Due to default methods, unless a method is found on a superclass,
-        // methods declared in any superinterface needs to be considered.
-        // Collect all candidates declared in superinterfaces in {@code
-        // allInterfaceCandidates} and select the most specific if no match on
-        // a superclass is found.
-
-        // Must _not_ return root methods
-        Method res;
-        // Search declared public methods
-        if ((res = searchMethods(privateGetDeclaredMethods(true),
-                                 name,
-                                 parameterTypes)) != null) {
-            if (includeStaticMethods || !Modifier.isStatic(res.getModifiers()))
-                return res;
-        }
-        // Search superclass's methods
-        if (!isInterface()) {
-            Class<? super T> c = getSuperclass();
-            if (c != null) {
-                if ((res = c.getMethod0(name, parameterTypes, true)) != null) {
-                    return res;
-                }
-            }
-        }
-        // Search superinterfaces' methods
-        Class<?>[] interfaces = getInterfaces();
-        for (Class<?> c : interfaces)
-            if ((res = c.getMethod0(name, parameterTypes, false)) != null)
-                allInterfaceCandidates.add(res);
-        // Not found
-        return null;
     }
 
+    // Returns a "root" Constructor object. This Constructor object must NOT
+    // be propagated to the outside world, but must instead be copied
+    // via ReflectionFactory.copyConstructor.
     private Constructor<T> getConstructor0(Class<?>[] parameterTypes,
                                         int which) throws NoSuchMethodException
     {
+        ReflectionFactory fact = getReflectionFactory();
         Constructor<T>[] constructors = privateGetDeclaredConstructors((which == Member.PUBLIC));
         for (Constructor<T> constructor : constructors) {
             if (arrayContentsEq(parameterTypes,
-                                constructor.getParameterTypes())) {
+                                fact.getExecutableSharedParameterTypes(constructor))) {
-                return getReflectionFactory().copyConstructor(constructor);
+                return constructor;
             }
         }
         throw new NoSuchMethodException(getName() + ".<init>" + argumentTypesToString(parameterTypes));

jdk/src/java.base/share/classes/java/lang/PublicMethods.java

@@ -0,0 +1,272 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package java.lang;
+
+import jdk.internal.reflect.ReflectionFactory;
+
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.security.AccessController;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * A collection of most specific public methods. Methods are added to it using
+ * {@link #merge(Method)} method. Only the most specific methods for a
+ * particular signature are kept.
+ */
+final class PublicMethods {
+
+    /**
+     * a map of (method name, parameter types) -> linked list of Method(s)
+     */
+    private final Map<Key, MethodList> map = new LinkedHashMap<>();
+
+    /**
+     * keeps track of the number of collected methods
+     */
+    private int methodCount;
+
+    /**
+     * Merges new method with existing methods. New method is either
+     * ignored (if a more specific method with same signature exists) or added
+     * to the collection. When it is added to the collection, it may replace one
+     * or more existing methods with same signature if they are less specific
+     * than added method.
+     * See comments in code...
+     */
+    void merge(Method method) {
+        Key key = new Key(method);
+        MethodList existing = map.get(key);
+        int xLen = existing == null ? 0 : existing.length();
+        MethodList merged = MethodList.merge(existing, method);
+        methodCount += merged.length() - xLen;
+        // replace if head of list changed
+        if (merged != existing) {
+            map.put(key, merged);
+        }
+    }
+
+    /**
+     * Dumps methods to array.
+     */
+    Method[] toArray() {
+        Method[] array = new Method[methodCount];
+        int i = 0;
+        for (MethodList ml : map.values()) {
+            for (; ml != null; ml = ml.next) {
+                array[i++] = ml.method;
+            }
+        }
+        return array;
+    }
+
+    /**
+     * Method (name, parameter types) tuple.
+     */
+    private static final class Key {
+        private static final ReflectionFactory reflectionFactory =
+            AccessController.doPrivileged(
+                new ReflectionFactory.GetReflectionFactoryAction());
+
+        private final String name; // must be interned (as from Method.getName())
+        private final Class<?>[] ptypes;
+
+        Key(Method method) {
+            name = method.getName();
+            ptypes = reflectionFactory.getExecutableSharedParameterTypes(method);
+        }
+
+        static boolean matches(Method method,
+                               String name, // may not be interned
+                               Class<?>[] ptypes) {
+            return method.getName().equals(name) &&
+                   Arrays.equals(
+                       reflectionFactory.getExecutableSharedParameterTypes(method),
+                       ptypes
+                   );
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (!(o instanceof Key)) return false;
+            Key that = (Key) o;
+            //noinspection StringEquality (guaranteed interned String(s))
+            return name == that.name &&
+                   Arrays.equals(ptypes, that.ptypes);
+        }
+
+        @Override
+        public int hashCode() {
+            return System.identityHashCode(name) + // guaranteed interned String
+                   31 * Arrays.hashCode(ptypes);
+        }
+    }
+
+    /**
+     * Node of a inked list containing Method(s) sharing the same
+     * (name, parameter types) tuple.
+     */
+    static final class MethodList {
+        Method method;
+        MethodList next;
+
+        private MethodList(Method method) {
+            this.method = method;
+        }
+
+        /**
+         * @return the head of a linked list containing given {@code methods}
+         *         filtered by given method {@code name}, parameter types
+         *         {@code ptypes} and including or excluding static methods as
+         *         requested by {@code includeStatic} flag.
+         */
+        static MethodList filter(Method[] methods, String name,
+                                 Class<?>[] ptypes, boolean includeStatic) {
+            MethodList head = null, tail = null;
+            for (Method method : methods) {
+                if ((includeStatic || !Modifier.isStatic(method.getModifiers())) &&
+                    Key.matches(method, name, ptypes)) {
+                    if (tail == null) {
+                        head = tail = new MethodList(method);
+                    } else {
+                        tail = tail.next = new MethodList(method);
+                    }
+                }
+            }
+            return head;
+        }
+
+        /**
+         * This method should only be called with the {@code head} (possibly null)
+         * of a list of Method(s) that share the same (method name, parameter types)
+         * and another {@code methodList} that also contains Method(s) with the
+         * same and equal (method name, parameter types) as the 1st list.
+         * It modifies the 1st list and returns the head of merged list
+         * containing only the most specific methods for each signature
+         * (i.e. return type). The returned head of the merged list may or
+         * may not be the same as the {@code head} of the given list.
+         * The given {@code methodList} is not modified.
+         */
+        static MethodList merge(MethodList head, MethodList methodList) {
+            for (MethodList ml = methodList; ml != null; ml = ml.next) {
+                head = merge(head, ml.method);
+            }
+            return head;
+        }
+
+        private static MethodList merge(MethodList head, Method method) {
+            Class<?> dclass = method.getDeclaringClass();
+            Class<?> rtype = method.getReturnType();
+            MethodList prev = null;
+            for (MethodList l = head; l != null; l = l.next) {
+                // eXisting method
+                Method xmethod = l.method;
+                // only merge methods with same signature:
+                // (return type, name, parameter types) tuple
+                // as we only keep methods with same (name, parameter types)
+                // tuple together in one list, we only need to check return type
+                if (rtype == xmethod.getReturnType()) {
+                    Class<?> xdclass = xmethod.getDeclaringClass();
+                    if (dclass.isInterface() == xdclass.isInterface()) {
+                        // both methods are declared by interfaces
+                        // or both by classes
+                        if (dclass.isAssignableFrom(xdclass)) {
+                            // existing method is the same or overrides
+                            // new method - ignore new method
+                            return head;
+                        }
+                        if (xdclass.isAssignableFrom(dclass)) {
+                            // new method overrides existing
+                            // method - knock out existing method
+                            if (prev != null) {
+                                prev.next = l.next;
+                            } else {
+                                head = l.next;
+                            }
+                            // keep iterating
+                        } else {
+                            // unrelated (should only happen for interfaces)
+                            prev = l;
+                            // keep iterating
+                        }
+                    } else if (dclass.isInterface()) {
+                        // new method is declared by interface while
+                        // existing method is declared by class -
+                        // ignore new method
+                        return head;
+                    } else /* xdclass.isInterface() */ {
+                        // new method is declared by class while
+                        // existing method is declared by interface -
+                        // knock out existing method
+                        if (prev != null) {
+                            prev.next = l.next;
+                        } else {
+                            head = l.next;
+                        }
+                        // keep iterating
+                    }
+                } else {
+                    // distinct signatures
+                    prev = l;
+                    // keep iterating
+                }
+            }
+            // append new method to the list
+            if (prev == null) {
+                head = new MethodList(method);
+            } else {
+                prev.next = new MethodList(method);
+            }
+            return head;
+        }
+
+        private int length() {
+            int len = 1;
+            for (MethodList ml = next; ml != null; ml = ml.next) {
+                len++;
+            }
+            return len;
+        }
+
+        /**
+         * @return 1st method in list with most specific return type
+         */
+        Method getMostSpecific() {
+            Method m = method;
+            Class<?> rt = m.getReturnType();
+            for (MethodList ml = next; ml != null; ml = ml.next) {
+                Method m2 = ml.method;
+                Class<?> rt2 = m2.getReturnType();
+                if (rt2 != rt && rt.isAssignableFrom(rt2)) {
+                    // found more specific return type
+                    m = m2;
+                    rt = rt2;
+                }
+            }
+            return m;
+        }
+    }
+}

jdk/src/java.base/share/classes/java/lang/reflect/Constructor.java

@@ -240,6 +240,11 @@ public final class Constructor<T> extends Executable {
     }
 
 
+    @Override
+    Class<?>[] getSharedParameterTypes() {
+        return parameterTypes;
+    }
+
     /**
      * {@inheritDoc}
      */

jdk/src/java.base/share/classes/java/lang/reflect/Executable.java

@@ -222,6 +222,10 @@ public abstract class Executable extends AccessibleObject
      */
     public abstract TypeVariable<?>[] getTypeParameters();
 
+    // returns shared array of parameter types - must never give it out
+    // to the untrusted code...
+    abstract Class<?>[] getSharedParameterTypes();
+
     /**
      * Returns an array of {@code Class} objects that represent the formal
      * parameter types, in declaration order, of the executable

jdk/src/java.base/share/classes/java/lang/reflect/Method.java

@@ -290,6 +290,11 @@ public final class Method extends Executable {
       } else { return getReturnType();}
     }
 
+    @Override
+    Class<?>[] getSharedParameterTypes() {
+        return parameterTypes;
+    }
+
     /**
      * {@inheritDoc}
      */

jdk/src/java.base/share/classes/java/lang/reflect/ReflectAccess.java

@@ -132,6 +132,10 @@ class ReflectAccess implements jdk.internal.reflect.LangReflectAccess {
         return ex.getTypeAnnotationBytes();
     }
 
+    public Class<?>[] getExecutableSharedParameterTypes(Executable ex) {
+        return ex.getSharedParameterTypes();
+    }
+
     //
     // Copying routines, needed to quickly fabricate new Field,
     // Method, and Constructor objects from templates

jdk/src/java.base/share/classes/jdk/internal/reflect/LangReflectAccess.java

@@ -96,6 +96,9 @@ public interface LangReflectAccess {
     /** Gets the "parameterAnnotations" field from a Constructor (used for serialization) */
     public byte[] getConstructorParameterAnnotations(Constructor<?> c);
 
+    /** Gets the shared array of parameter types of an Executable. */
+    public Class<?>[] getExecutableSharedParameterTypes(Executable ex);
+
     //
     // Copying routines, needed to quickly fabricate new Field,
     // Method, and Constructor objects from templates

jdk/src/java.base/share/classes/jdk/internal/reflect/ReflectionFactory.java

@@ -345,6 +345,10 @@ public class ReflectionFactory {
         return langReflectAccess().getExecutableTypeAnnotationBytes(ex);
     }
 
+    public Class<?>[] getExecutableSharedParameterTypes(Executable ex) {
+        return langReflectAccess().getExecutableSharedParameterTypes(ex);
+    }
+
     //--------------------------------------------------------------------------
     //
     // Routines used by serialization

jdk/test/java/lang/Class/getMethods/StarInheritance.java

@@ -49,7 +49,7 @@ interface B3 extends D3 { void m(); }
 interface C3 extends D3 { void m(); }
 interface D3 { void m() ; }
 
-// B.m, D.m
+// B.m
 interface A4 extends B4, C4 {}
 interface B4 extends D4 { void m(); }
 interface C4 extends D4 {}
@@ -92,7 +92,7 @@ public class StarInheritance {
         Class [] l3 = {B3.class, C3.class};
         test(A3.class.getMethods(), new ArrayList(Arrays.asList(l3)));
 
-        Class [] l4 = {B4.class, D4.class};
+        Class [] l4 = {B4.class};
         test(A4.class.getMethods(), new ArrayList(Arrays.asList(l4)));
     }
 }

jdk/test/java/lang/reflect/DefaultMethodMembers/FilterNotMostSpecific.java

@@ -36,9 +36,8 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Set;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.testng.annotations.DataProvider;
 import org.testng.annotations.Test;
@@ -55,7 +54,7 @@ public class FilterNotMostSpecific {
         for (MethodDesc expected : expectedMethods) {
             if (expected.isGetMethodReturn()) {
                 try {
-                    Method m = iface.getMethod(expected.name());
+                    Method m = iface.getMethod(expected.name(), expected.parameterTypes());
                     if (!assertMatch(expected, m))
                         fail(failMsg(expected, m, iface));
                     else
@@ -72,26 +71,18 @@ public class FilterNotMostSpecific {
     public void testGetMethods(Class<?> iface) {
         List<Method> foundMethods = filterObjectMethods(iface.getMethods());
         MethodDesc[] expectedMethods = iface.getAnnotationsByType(MethodDesc.class);
-        Set<Method> used = new HashSet<>();
 
         for (MethodDesc expected : expectedMethods) {
             boolean found = false;
-
             for (Method m : foundMethods) {
-                if (used.contains(m))
+                if (assertMatch(expected, m)) {
-                    continue;
-
-                if(expected.name().equals(m.getName()) &&
-                    expected.declaringClass() ==m.getDeclaringClass()) {
-
                     found = true;
-                    assertMatch(expected, m);
-                    used.add(m);
                     break;
                 }
             }
-            if (! found)
+            if (!found)
-                fail("On: "+ iface +"\nDid not find " + toMethodString(expected) + " among " + foundMethods);
+                fail("On: "+ iface +"\nDid not find " + toMethodString(expected) +
+                     " among " + foundMethods);
         }
         assertEquals(foundMethods.size(), expectedMethods.length,
                 "\non: " + iface +
@@ -104,6 +95,11 @@ public class FilterNotMostSpecific {
             return false;
         if (expected.declaringClass() != m.getDeclaringClass())
             return false;
+        if (!Arrays.equals(expected.parameterTypes(), m.getParameterTypes()))
+            return false;
+        if (expected.returnType() != NotSpecified.class &&
+            expected.returnType() != m.getReturnType())
+            return false;
 
         if (expected.kind() == MethodKind.ABSTRACT)
             assertTrue(Modifier.isAbstract(m.getModifiers()), m + " should be ABSTRACT");
@@ -128,8 +124,13 @@ public class FilterNotMostSpecific {
     }
 
     private String toMethodString(MethodDesc m) {
-        return m.declaringClass().getSimpleName().toString() + "." +
+        return (m.returnType() != NotSpecified.class
-            m.name() + "()";
+                ? m.returnType().getSimpleName() + " "
+                : "") +
+               m.declaringClass().getSimpleName().toString() + "." +
+               m.name() + Stream.of(m.parameterTypes())
+                                .map(cl -> cl.getSimpleName())
+                                .collect(Collectors.joining(", ", "(", ")"));
     }
 
     private List<String> toMethodStrings(MethodDesc[] m) {
@@ -142,11 +143,16 @@ public class FilterNotMostSpecific {
     @Repeatable(MethodDescs.class)
     public @interface MethodDesc {
         String name();
+        Class<?> returnType() default NotSpecified.class;
+        Class<?>[] parameterTypes() default {};
         Class<?> declaringClass();
         MethodKind kind() default MethodKind.ABSTRACT;
         boolean isGetMethodReturn() default false;
     }
 
+    // special type marking a not-specified return type in @MethodDesc
+    interface NotSpecified {}
+
     @Retention(RetentionPolicy.RUNTIME)
     public @interface MethodDescs {
         MethodDesc[] value();
@@ -172,22 +178,18 @@ public class FilterNotMostSpecific {
 
     @MethodDesc(name="nonDefault", declaringClass=Jbis.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=I.class)
     interface P2 extends Jbis, Jprim {}
 
     @MethodDesc(name="nonDefault", declaringClass=Jbis.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=I.class)
     interface P3 extends Jbis, Jprim, I {}
 
-    @MethodDesc(name="nonDefault", declaringClass=I.class,
+    @MethodDesc(name="nonDefault", declaringClass=J.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=J.class)
     interface P4 extends I, J {}
 
     @MethodDesc(name="nonDefault", declaringClass=J.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=I.class)
     interface P5 extends J, I {}
 
     @MethodDesc(name="nonDefault", declaringClass=J.class,
@@ -198,14 +200,12 @@ public class FilterNotMostSpecific {
             isGetMethodReturn=true)
     interface K1M extends J { void nonDefault(); }
 
-    @MethodDesc(name="nonDefault", declaringClass=I.class,
+    @MethodDesc(name="nonDefault", declaringClass=J.class,
-            isGetMethodReturn=true)
+             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=J.class)
+   interface K2 extends I, J {}
-    interface K2 extends I, J {}
 
     @MethodDesc(name="nonDefault", declaringClass=J.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=I.class)
     interface K2O extends J, I {}
 
     @MethodDesc(name="nonDefault", declaringClass=K2M.class,
@@ -244,21 +244,18 @@ public class FilterNotMostSpecific {
 
     @MethodDesc(name="isDefault", declaringClass=M.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
     @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
     interface N2 extends M, L {}
 
     @MethodDesc(name="isDefault", declaringClass=M.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class,
+    @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
     interface N22 extends L, M {}
 
     @MethodDesc(name="isDefault", declaringClass=N2D.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
     @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
     interface N2D extends M, L { default void isDefault() {}}
@@ -277,48 +274,36 @@ public class FilterNotMostSpecific {
 
     @MethodDesc(name="isDefault", declaringClass=N2DN.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class,
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface O1 extends L, M, N2DN {}
 
     @MethodDesc(name="isDefault", declaringClass=N2DN.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
-    @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface O2 extends M, N2DN, L {}
 
     @MethodDesc(name="isDefault", declaringClass=N2DN.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
     @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
     interface O3 extends N2DN, L, M {}
 
     @MethodDesc(name="isDefault", declaringClass=N2DN.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class,
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     abstract class C1 implements L, M, N2DN {}
 
     @MethodDesc(name="isDefault", declaringClass=N2DN.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
-    @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     abstract class C2 implements M, N2DN, L {}
 
     @MethodDesc(name="isDefault", declaringClass=N2DN.class,
             kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
     @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
     abstract class C3 implements N2DN, L, M {}
@@ -345,88 +330,54 @@ public class FilterNotMostSpecific {
 
     @MethodDesc(name="isDefault", declaringClass=R1.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class,
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface R1 extends L, M, N2DN { void isDefault(); }
 
     @MethodDesc(name="isDefault", declaringClass=R2.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
-    @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface R2 extends M, N2DN, L { void isDefault(); }
 
     @MethodDesc(name="isDefault", declaringClass=R3.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
     @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
     interface R3 extends N2DN, L, M { void isDefault(); }
 
-    // this one is strange but logical, getMethod finds N2DN first, which is
+    @MethodDesc(name="isDefault", declaringClass=R1.class,
-    // default but not the most specific
+            isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=N2DN.class,
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=R1.class)
-    @MethodDesc(name="nonDefault", declaringClass=L.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface R4 extends L, M, N2DN, R1 {}
 
-    // this one is strange but logical, getMethod finds N2DN first, which is
+    @MethodDesc(name="isDefault", declaringClass=R2.class,
-    // default but not the most specific
+            isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=N2DN.class,
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=R2.class)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
-    @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface R5 extends M, N2DN, R2, L {}
 
-    // this one is strange but logical, getMethod finds N2DN first, which is
+    @MethodDesc(name="isDefault", declaringClass=R3.class,
-    // default but not the most specific
+            isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=N2DN.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=R3.class)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
     @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
     interface R6 extends N2DN, R3, L, M {}
 
-    // the following three finds the "right" one
     @MethodDesc(name="isDefault", declaringClass=R1.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=N2DN.class,
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
-            kind=MethodKind.DEFAULT)
-    @MethodDesc(name="nonDefault", declaringClass=L.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface R7 extends L, M, R1, N2DN {}
 
     @MethodDesc(name="isDefault", declaringClass=R2.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=N2DN.class,
+    @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
-            kind=MethodKind.DEFAULT)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
-    @MethodDesc(name="nonDefault", declaringClass=M.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=N2DN.class)
     interface R8 extends M, R2, N2DN, L {}
 
     @MethodDesc(name="isDefault", declaringClass=R3.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="isDefault", declaringClass=N2DN.class,
-            kind=MethodKind.DEFAULT)
-    @MethodDesc(name="nonDefault", declaringClass=L.class)
-    @MethodDesc(name="nonDefault", declaringClass=M.class)
     @MethodDesc(name="nonDefault", declaringClass=N2DN.class,
             isGetMethodReturn=true)
     interface R9 extends R3, N2DN, L, M {}
@@ -445,51 +396,40 @@ public class FilterNotMostSpecific {
 
     interface Z3 extends Z2, Z1 { void z(); }
 
-    @MethodDesc(name="z", declaringClass=Z2.class,
+    @MethodDesc(name="z", declaringClass=Z3.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
+            isGetMethodReturn = true)
-    @MethodDesc(name="z", declaringClass=Z3.class)
     interface Z41 extends Z1, Z2, Z3 { }
 
-    @MethodDesc(name="z", declaringClass=Z2.class,
+    @MethodDesc(name="z", declaringClass=Z3.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
+            isGetMethodReturn = true)
-    @MethodDesc(name="z", declaringClass=Z3.class)
     interface Z42 extends Z2, Z3, Z1 { }
 
     @MethodDesc(name="z", declaringClass=Z3.class,
-            isGetMethodReturn=true)
+            isGetMethodReturn = true)
-    @MethodDesc(name="z", declaringClass=Z2.class,
-            kind=MethodKind.DEFAULT)
     interface Z43 extends Z3, Z1, Z2 { }
 
-    @MethodDesc(name="z", declaringClass=Z2.class,
+    @MethodDesc(name="z", declaringClass=Z3.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
+            isGetMethodReturn = true)
-    @MethodDesc(name="z", declaringClass=Z3.class)
     abstract class ZC41 implements Z1, Z2, Z3 { }
 
-    @MethodDesc(name="z", declaringClass=Z2.class,
+    @MethodDesc(name="z", declaringClass=Z3.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
+            isGetMethodReturn = true)
-    @MethodDesc(name="z", declaringClass=Z3.class)
     abstract class ZC42 implements Z2, Z3, Z1 { }
 
     @MethodDesc(name="z", declaringClass=Z3.class,
-            isGetMethodReturn=true)
+            isGetMethodReturn = true)
-    @MethodDesc(name="z", declaringClass=Z2.class,
-            kind=MethodKind.DEFAULT)
     abstract class ZC43 implements Z3, Z1, Z2 { }
 
     // More reabstraction + concretization
     interface X1 { default void x() {} }
     interface X2 extends X1 { void x(); }
 
-    @MethodDesc(name="x", declaringClass=X1.class,
+    @MethodDesc(name="x", declaringClass=X2.class,
-            kind=MethodKind.DEFAULT, isGetMethodReturn=true)
+            isGetMethodReturn=true)
-    @MethodDesc(name="x", declaringClass=X2.class)
     interface X31 extends X1, X2 {}
 
     @MethodDesc(name="x", declaringClass=X2.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="x", declaringClass=X1.class,
-            kind=MethodKind.DEFAULT)
     interface X32 extends X2, X1 {}
 
     @MethodDesc(name="x", declaringClass=X3.class,
@@ -524,85 +464,107 @@ public class FilterNotMostSpecific {
 
     interface K extends I, J { void nonDefault(); }
 
-    @MethodDesc(name="nonDefault", declaringClass=I.class,
+    @MethodDesc(name="nonDefault", declaringClass=K.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=J.class)
-    @MethodDesc(name="nonDefault", declaringClass=K.class)
     abstract class ZZ1 implements I, J, K {}
 
-    @MethodDesc(name="nonDefault", declaringClass=I.class,
+    @MethodDesc(name="nonDefault", declaringClass=K.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=J.class)
-    @MethodDesc(name="nonDefault", declaringClass=K.class)
     abstract class ZZ2 extends ZZ1 implements K, I, J {}
 
-    @MethodDesc(name="nonDefault", declaringClass=I.class,
+    @MethodDesc(name="nonDefault", declaringClass=K.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="nonDefault", declaringClass=J.class)
-    @MethodDesc(name="nonDefault", declaringClass=K.class)
     abstract class ZZ3 extends ZZ2 implements J, K, I {}
 
-    // bridges
+    // bridges...
-    interface B1A { Object m(); }
-    interface B1B extends B1A { Map m(); }
 
-    @MethodDesc(name="m", declaringClass=B1C.class,
+    interface B1 { Object m(); }
-            isGetMethodReturn=true)
+    interface B2A extends B1 { Map m(); }
-    @MethodDesc(name="m", declaringClass=B1C.class,
+    interface B2B extends B1 { HashMap m(); }
-            kind=MethodKind.DEFAULT)
-    @MethodDesc(name="m", declaringClass=B1C.class,
-            kind=MethodKind.DEFAULT)
-    interface B1C extends B1B { HashMap m(); }
 
-    @MethodDesc(name="m", declaringClass=B2.class,
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B3A.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=Map.class, declaringClass=B3A.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=HashMap.class, declaringClass=B3A.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="m", declaringClass=B2.class,
+    interface B3A extends B2A { HashMap m(); }
-            kind=MethodKind.DEFAULT)
-    @MethodDesc(name="m", declaringClass=B2.class,
-            kind=MethodKind.DEFAULT)
-    interface B2 extends B1C { HashMap m(); }
 
-    @MethodDesc(name="m", declaringClass=B2.class, //HahsMap
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B4A.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=Map.class, declaringClass=B4A.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=HashMap.class, declaringClass= B4A.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="m", declaringClass=B2.class, //Map
+    interface B4A extends B3A { HashMap m(); }
-            kind=MethodKind.DEFAULT)
-    @MethodDesc(name="m", declaringClass=B2.class, //Object
-            kind=MethodKind.DEFAULT)
-    interface B3A extends B2, B1A {}
 
-    // this one is funny since HashMap isn't a bridge thus not a default
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B4A.class,
-    @MethodDesc(name="m", declaringClass=B2.class, //HashMap
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=Map.class, declaringClass=B4A.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=HashMap.class, declaringClass= B4A.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="m", declaringClass=B2.class, //Map
+    interface B5A2 extends B4A, B1 {}
-            kind=MethodKind.DEFAULT)
+
-    @MethodDesc(name="m", declaringClass=B2.class, //Object
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B4A.class,
-            kind=MethodKind.DEFAULT)
+            kind = MethodKind.DEFAULT)
-    @MethodDesc(name="m", declaringClass=B1C.class) //HashMap
+    @MethodDesc(name="m", returnType=Map.class, declaringClass=B4A.class,
-    interface B3B extends B2, B1C {}
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=HashMap.class, declaringClass= B4A.class,
+            isGetMethodReturn=true)
+    interface B5A4A extends B4A, B3A {}
+
+    // ... + most specific return type for getMethod from two unrelated interfaces
+
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B2A.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B2B.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=Map.class, declaringClass=B2A.class)
+    @MethodDesc(name="m", returnType=HashMap.class, declaringClass=B2B.class,
+            isGetMethodReturn=true)
+    interface B3AB extends B2A, B2B {}
+
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B2A.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=Object.class, declaringClass=B2B.class,
+            kind = MethodKind.DEFAULT)
+    @MethodDesc(name="m", returnType=Map.class, declaringClass=B2A.class)
+    @MethodDesc(name="m", returnType=HashMap.class, declaringClass=B2B.class,
+            isGetMethodReturn=true)
+    interface B3BA extends B2B, B2A {}
 
     // same name different params type
     interface A1 { void m(); void m(int i); void m(int i, int j); }
     interface A2A extends A1 { void m(); void m(int i); void m(int i, int j); }
     interface A2B extends A1 { void m(); void m(int i); default void m(int i, int j) {} }
 
-    @MethodDesc(name="m", declaringClass=A1.class,
+    @MethodDesc(name="m", parameterTypes = {}, declaringClass=A2A.class,
+            isGetMethodReturn=true)
+    @MethodDesc(name="m", parameterTypes = {int.class}, declaringClass=A2A.class,
+            isGetMethodReturn=true)
+    @MethodDesc(name="m", parameterTypes = {int.class, int.class}, declaringClass=A2A.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="m", declaringClass=A1.class)
-    @MethodDesc(name="m", declaringClass=A1.class)
-    @MethodDesc(name="m", declaringClass=A2A.class)
-    @MethodDesc(name="m", declaringClass=A2A.class)
-    @MethodDesc(name="m", declaringClass=A2A.class)
     interface A3A extends A1, A2A {}
 
-    @MethodDesc(name="m", declaringClass=A1.class,
+    @MethodDesc(name="m", parameterTypes = {}, declaringClass=A2B.class,
             isGetMethodReturn=true)
-    @MethodDesc(name="m", declaringClass=A1.class)
+    @MethodDesc(name="m", parameterTypes = {int.class}, declaringClass=A2B.class,
-    @MethodDesc(name="m", declaringClass=A2B.class)
+            isGetMethodReturn=true)
-    @MethodDesc(name="m", declaringClass=A2B.class)
+    @MethodDesc(name="m", parameterTypes = {int.class, int.class}, declaringClass=A2B.class,
-    @MethodDesc(name="m", declaringClass=A2B.class,
+            kind = MethodKind.DEFAULT, isGetMethodReturn=true)
-            kind=MethodKind.DEFAULT)
     interface A3B extends A1, A2B {}
 
+    // method in directly implemented interface overrides interface method
+    // inherited by superclass
+
+    interface E { void m(); }
+    interface F extends E { void m(); }
+    abstract class G implements E {}
+
+    @MethodDesc(name="m", declaringClass=F.class, isGetMethodReturn=true)
+    abstract class H extends G implements F {}
+
     @DataProvider
     public Object[][] getCases() { return CASES; }
     public static final Class<?>[][] CASES =  {
@@ -680,12 +642,16 @@ public class FilterNotMostSpecific {
         { XC42.class },
         { XC43.class },
 
-        { B1C.class },
-        { B2.class },
         { B3A.class },
-        { B3B.class },
+        { B4A.class },
+        { B5A2.class },
+        { B5A4A.class },
+        { B3AB.class },
+        { B3BA.class },
 
         { A3A.class },
         { A3B.class },
+
+        { H.class },
     };
 }

jdk/test/java/lang/reflect/PublicMethods/PublicMethodsTest.java

@@ -0,0 +1,529 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import javax.tools.Diagnostic;
+import javax.tools.DiagnosticListener;
+import javax.tools.FileObject;
+import javax.tools.ForwardingJavaFileManager;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaFileObject;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.StandardJavaFileManager;
+import javax.tools.StandardLocation;
+import javax.tools.ToolProvider;
+import java.io.BufferedReader;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.UncheckedIOException;
+import java.lang.reflect.Method;
+import java.net.URI;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+import static java.util.stream.Collectors.joining;
+import static java.util.stream.Collectors.toMap;
+
+/*
+ * @test
+ * @bug 8062389
+ * @summary Nearly exhaustive test of Class.getMethod() and Class.getMethods()
+ * @run main PublicMethodsTest
+ */
+public class PublicMethodsTest {
+
+    public static void main(String[] args) {
+        Case c = new Case1();
+
+        int[] diffs = new int[1];
+        try (Stream<Map.Entry<int[], Map<String, String>>>
+                 expected = expectedResults(c)) {
+            diffResults(c, expected)
+                .forEach(diff -> {
+                    System.out.println(diff);
+                    diffs[0]++;
+                });
+        }
+
+        if (diffs[0] > 0) {
+            throw new RuntimeException(
+                "There were " + diffs[0] + " differences.");
+        }
+    }
+
+    // use this to generate .results file for particular case
+    public static class Generate {
+        public static void main(String[] args) {
+            Case c = new Case1();
+            dumpResults(generateResults(c))
+                .forEach(System.out::println);
+        }
+    }
+
+    interface Case {
+        Pattern PLACEHOLDER_PATTERN = Pattern.compile("\\$\\{(.+?)}");
+
+        // possible variants of interface method
+        List<String> INTERFACE_METHODS = List.of(
+            "", "void m();", "default void m() {}", "static void m() {}"
+        );
+
+        // possible variants of class method
+        List<String> CLASS_METHODS = List.of(
+            "", "public abstract void m();",
+            "public void m() {}", "public static void m() {}"
+        );
+
+        // template with placeholders parsed with PLACEHOLDER_PATTERN
+        String template();
+
+        // map of replacementKey (== PLACEHOLDER_PATTERN captured group #1) ->
+        // list of possible replacements
+        Map<String, List<String>> replacements();
+
+        // ordered list of replacement keys
+        List<String> replacementKeys();
+
+        // names of types occurring in the template
+        List<String> classNames();
+    }
+
+    static class Case1 implements Case {
+
+        private static final String TEMPLATE = Stream.of(
+            "interface I { ${I} }",
+            "interface J { ${J} }",
+            "interface K extends I, J { ${K} }",
+            "abstract class C { ${C} }",
+            "abstract class D extends C implements I { ${D} }",
+            "abstract class E extends D implements J, K { ${E} }"
+        ).collect(joining("\n"));
+
+        private static final Map<String, List<String>> REPLACEMENTS = Map.of(
+            "I", INTERFACE_METHODS,
+            "J", INTERFACE_METHODS,
+            "K", INTERFACE_METHODS,
+            "C", CLASS_METHODS,
+            "D", CLASS_METHODS,
+            "E", CLASS_METHODS
+        );
+
+        private static final List<String> REPLACEMENT_KEYS = REPLACEMENTS
+            .keySet().stream().sorted().collect(Collectors.toList());
+
+        @Override
+        public String template() {
+            return TEMPLATE;
+        }
+
+        @Override
+        public Map<String, List<String>> replacements() {
+            return REPLACEMENTS;
+        }
+
+        @Override
+        public List<String> replacementKeys() {
+            return REPLACEMENT_KEYS;
+        }
+
+        @Override
+        public List<String> classNames() {
+            // just by accident, names of classes are equal to replacement keys
+            // (this need not be the case in general)
+            return REPLACEMENT_KEYS;
+        }
+    }
+
+    // generate all combinations as a tuple of indexes into lists of
+    // replacements. The index of the element in int[] tuple represents the index
+    // of the key in replacementKeys() list. The value of the element in int[] tuple
+    // represents the index of the replacement string in list of strings in the
+    // value of the entry of replacements() map with the corresponding key.
+    static Stream<int[]> combinations(Case c) {
+        int[] sizes = c.replacementKeys().stream()
+                       .mapToInt(key -> c.replacements().get(key).size())
+                       .toArray();
+
+        return Stream.iterate(
+            new int[sizes.length],
+            state -> state != null,
+            state -> {
+                int[] newState = state.clone();
+                for (int i = 0; i < state.length; i++) {
+                    if (++newState[i] < sizes[i]) {
+                        return newState;
+                    }
+                    newState[i] = 0;
+                }
+                // wrapped-around
+                return null;
+            }
+        );
+    }
+
+    // given the combination of indexes, return the expanded template
+    static String expandTemplate(Case c, int[] combination) {
+
+        // 1st create a map: key -> replacement string
+        Map<String, String> map = new HashMap<>(combination.length * 4 / 3 + 1);
+        for (int i = 0; i < combination.length; i++) {
+            String key = c.replacementKeys().get(i);
+            String repl = c.replacements().get(key).get(combination[i]);
+            map.put(key, repl);
+        }
+
+        return Case.PLACEHOLDER_PATTERN
+            .matcher(c.template())
+            .replaceAll(match -> map.get(match.group(1)));
+    }
+
+    /**
+     * compile expanded template into a ClassLoader that sees compiled classes
+     */
+    static ClassLoader compile(String source) throws CompileException {
+        JavaCompiler javac = ToolProvider.getSystemJavaCompiler();
+        if (javac == null) {
+            throw new AssertionError("No Java compiler tool found.");
+        }
+
+        ErrorsCollector errorsCollector = new ErrorsCollector();
+        StandardJavaFileManager standardJavaFileManager =
+            javac.getStandardFileManager(errorsCollector, Locale.ROOT,
+                                         Charset.forName("UTF-8"));
+        TestFileManager testFileManager = new TestFileManager(
+            standardJavaFileManager, source);
+
+        JavaCompiler.CompilationTask javacTask;
+        try {
+            javacTask = javac.getTask(
+                null, // use System.err
+                testFileManager,
+                errorsCollector,
+                null,
+                null,
+                List.of(testFileManager.getJavaFileForInput(
+                    StandardLocation.SOURCE_PATH,
+                    TestFileManager.TEST_CLASS_NAME,
+                    JavaFileObject.Kind.SOURCE))
+            );
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+
+        javacTask.call();
+
+        if (errorsCollector.hasError()) {
+            throw new CompileException(errorsCollector.getErrors());
+        }
+
+        return new TestClassLoader(ClassLoader.getSystemClassLoader(),
+                                   testFileManager);
+    }
+
+    static class CompileException extends Exception {
+        CompileException(List<Diagnostic<?>> diagnostics) {
+            super(diagnostics.stream()
+                             .map(diag -> diag.toString())
+                             .collect(Collectors.joining("\n")));
+        }
+    }
+
+    static class TestFileManager
+        extends ForwardingJavaFileManager<StandardJavaFileManager> {
+        static final String TEST_CLASS_NAME = "Test";
+
+        private final String testSource;
+        private final Map<String, ClassFileObject> classes = new HashMap<>();
+
+        TestFileManager(StandardJavaFileManager fileManager, String source) {
+            super(fileManager);
+            testSource = "public class " + TEST_CLASS_NAME + " {}\n" +
+                         source; // the rest of classes are package-private
+        }
+
+        @Override
+        public JavaFileObject getJavaFileForInput(Location location,
+                                                  String className,
+                                                  JavaFileObject.Kind kind)
+        throws IOException {
+            if (location == StandardLocation.SOURCE_PATH &&
+                kind == JavaFileObject.Kind.SOURCE &&
+                TEST_CLASS_NAME.equals(className)) {
+                return new SourceFileObject(className, testSource);
+            }
+            return super.getJavaFileForInput(location, className, kind);
+        }
+
+        private static class SourceFileObject extends SimpleJavaFileObject {
+            private final String source;
+
+            SourceFileObject(String className, String source) {
+                super(
+                    URI.create("memory:/src/" +
+                               className.replace('.', '/') + ".java"),
+                    Kind.SOURCE
+                );
+                this.source = source;
+            }
+
+            @Override
+            public CharSequence getCharContent(boolean ignoreEncodingErrors) {
+                return source;
+            }
+        }
+
+        @Override
+        public JavaFileObject getJavaFileForOutput(Location location,
+                                                   String className,
+                                                   JavaFileObject.Kind kind,
+                                                   FileObject sibling)
+        throws IOException {
+            if (kind == JavaFileObject.Kind.CLASS) {
+                ClassFileObject cfo = new ClassFileObject(className);
+                classes.put(className, cfo);
+                return cfo;
+            }
+            return super.getJavaFileForOutput(location, className, kind, sibling);
+        }
+
+        private static class ClassFileObject extends SimpleJavaFileObject {
+            final String className;
+            ByteArrayOutputStream byteArrayOutputStream;
+
+            ClassFileObject(String className) {
+                super(
+                    URI.create("memory:/out/" +
+                               className.replace('.', '/') + ".class"),
+                    Kind.CLASS
+                );
+                this.className = className;
+            }
+
+            @Override
+            public OutputStream openOutputStream() throws IOException {
+                return byteArrayOutputStream = new ByteArrayOutputStream();
+            }
+
+            byte[] getBytes() {
+                if (byteArrayOutputStream == null) {
+                    throw new IllegalStateException(
+                        "No class file written for class: " + className);
+                }
+                return byteArrayOutputStream.toByteArray();
+            }
+        }
+
+        byte[] getClassBytes(String className) {
+            ClassFileObject cfo = classes.get(className);
+            return (cfo == null) ? null : cfo.getBytes();
+        }
+    }
+
+    static class ErrorsCollector implements DiagnosticListener<JavaFileObject> {
+        private final List<Diagnostic<?>> errors = new ArrayList<>();
+
+        @Override
+        public void report(Diagnostic<? extends JavaFileObject> diagnostic) {
+            if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {
+                errors.add(diagnostic);
+            }
+        }
+
+        boolean hasError() {
+            return !errors.isEmpty();
+        }
+
+        List<Diagnostic<?>> getErrors() {
+            return errors;
+        }
+    }
+
+    static class TestClassLoader extends ClassLoader {
+        private final TestFileManager fileManager;
+
+        public TestClassLoader(ClassLoader parent, TestFileManager fileManager) {
+            super(parent);
+            this.fileManager = fileManager;
+        }
+
+        @Override
+        protected Class<?> findClass(String name) throws ClassNotFoundException {
+            byte[] classBytes = fileManager.getClassBytes(name);
+            if (classBytes == null) {
+                throw new ClassNotFoundException(name);
+            }
+            return defineClass(name, classBytes, 0, classBytes.length);
+        }
+    }
+
+    static Map<String, String> generateResult(Case c, ClassLoader cl) {
+        return
+            c.classNames()
+             .stream()
+             .map(cn -> {
+                 try {
+                     return Class.forName(cn, false, cl);
+                 } catch (ClassNotFoundException e) {
+                     throw new RuntimeException("Class not found: " + cn, e);
+                 }
+             })
+             .flatMap(clazz -> Stream.of(
+                 Map.entry(clazz.getName() + ".gM", generateGetMethodResult(clazz)),
+                 Map.entry(clazz.getName() + ".gMs", generateGetMethodsResult(clazz))
+             ))
+             .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+    }
+
+    static String generateGetMethodResult(Class<?> clazz) {
+        try {
+            Method m = clazz.getMethod("m");
+            return m.getDeclaringClass().getName() + "." + m.getName();
+        } catch (NoSuchMethodException e) {
+            return "-";
+        }
+    }
+
+    static String generateGetMethodsResult(Class<?> clazz) {
+        return Stream.of(clazz.getMethods())
+                     .filter(m -> m.getDeclaringClass() != Object.class)
+                     .map(m -> m.getDeclaringClass().getName()
+                               + "." + m.getName())
+                     .collect(Collectors.joining(", ", "[", "]"));
+    }
+
+    static Stream<Map.Entry<int[], Map<String, String>>> generateResults(Case c) {
+        return combinations(c)
+            .flatMap(comb -> {
+                String src = expandTemplate(c, comb);
+                ClassLoader cl;
+                try {
+                    cl = compile(src);
+                } catch (CompileException e) {
+                    // ignore uncompilable combinations
+                    return Stream.empty();
+                }
+                // compilation was successful -> generate result
+                return Stream.of(Map.entry(
+                    comb,
+                    generateResult(c, cl)
+                ));
+            });
+    }
+
+    static Stream<Map.Entry<int[], Map<String, String>>> expectedResults(Case c) {
+        try {
+            BufferedReader r = new BufferedReader(new InputStreamReader(
+                c.getClass().getResourceAsStream(
+                    c.getClass().getSimpleName() + ".results"),
+                "UTF-8"
+            ));
+
+            return parseResults(r.lines())
+                .onClose(() -> {
+                    try {
+                        r.close();
+                    } catch (IOException ioe) {
+                        throw new UncheckedIOException(ioe);
+                    }
+                });
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    static Stream<Map.Entry<int[], Map<String, String>>> parseResults(
+        Stream<String> lines
+    ) {
+        return lines
+            .map(l -> l.split(Pattern.quote("#")))
+            .map(lkv -> Map.entry(
+                Stream.of(lkv[0].split(Pattern.quote(",")))
+                      .mapToInt(Integer::parseInt)
+                      .toArray(),
+                Stream.of(lkv[1].split(Pattern.quote("|")))
+                      .map(e -> e.split(Pattern.quote("=")))
+                      .collect(toMap(ekv -> ekv[0], ekv -> ekv[1]))
+            ));
+    }
+
+    static Stream<String> dumpResults(
+        Stream<Map.Entry<int[], Map<String, String>>> results
+    ) {
+        return results
+            .map(le ->
+                     IntStream.of(le.getKey())
+                              .mapToObj(String::valueOf)
+                              .collect(joining(","))
+                     + "#" +
+                     le.getValue().entrySet().stream()
+                       .map(e -> e.getKey() + "=" + e.getValue())
+                       .collect(joining("|"))
+            );
+    }
+
+    static Stream<String> diffResults(
+        Case c,
+        Stream<Map.Entry<int[], Map<String, String>>> expectedResults
+    ) {
+        return expectedResults
+            .flatMap(exp -> {
+                int[] comb = exp.getKey();
+                Map<String, String> expected = exp.getValue();
+
+                String src = expandTemplate(c, comb);
+                ClassLoader cl;
+                try {
+                    cl = compile(src);
+                } catch (CompileException ce) {
+                    return Stream.of(src + "\n" +
+                                     "got compilation error: " + ce);
+                }
+
+                Map<String, String> actual = generateResult(c, cl);
+                if (actual.equals(expected)) {
+                    return Stream.empty();
+                } else {
+                    Map<String, String> diff = new HashMap<>(expected);
+                    diff.entrySet().removeAll(actual.entrySet());
+                    return Stream.of(
+                        diff.entrySet()
+                            .stream()
+                            .map(e -> "expected: " + e.getKey() + ": " +
+                                      e.getValue() + "\n" +
+                                      "  actual: " + e.getKey() + ": " +
+                                      actual.get(e.getKey()) + "\n")
+                            .collect(joining("\n", src + "\n\n", "\n"))
+                    );
+                }
+            });
+    }
+}