8207814: (proxy) upgrade the proxy class generator

Reviewed-by: mchung

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

@@ -420,17 +420,16 @@ public final class Method extends Executable {
 
     @Override
     String toShortString() {
-        StringBuilder sb = new StringBuilder("method ");
-        sb.append(getDeclaringClass().getTypeName()).append('.');
-        sb.append(getName());
-        sb.append('(');
-        StringJoiner sj = new StringJoiner(",");
+        return "method " + getDeclaringClass().getTypeName() +
+                '.' + toShortSignature();
+    }
+
+    String toShortSignature() {
+        StringJoiner sj = new StringJoiner(",", getName() + "(", ")");
         for (Class<?> parameterType : getParameterTypes()) {
             sj.add(parameterType.getTypeName());
         }
-        sb.append(sj);
-        sb.append(')');
-        return sb.toString();
+        return sj.toString();
     }
 
     /**

src/java.base/share/classes/java/lang/reflect/Proxy.java

@@ -49,6 +49,7 @@ import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
 import jdk.internal.loader.ClassLoaderValue;
 import sun.reflect.misc.ReflectUtil;
+import sun.security.action.GetBooleanAction;
 import sun.security.action.GetPropertyAction;
 import sun.security.util.SecurityConstants;
 
@@ -99,7 +100,7 @@ import static java.lang.module.ModuleDescriptor.Modifier.SYNTHETIC;
  * <li>A proxy class extends {@code java.lang.reflect.Proxy}.
  *
  * <li>A proxy class implements exactly the interfaces specified at its
- * creation, in the same order. Invoking {@link Class#getInterfaces getInterfaces}
+ * creation, in the same order. Invoking {@link Class#getInterfaces() getInterfaces}
  * on its {@code Class} object will return an array containing the same
  * list of interfaces (in the order specified at its creation), invoking
  * {@link Class#getMethods getMethods} on its {@code Class} object will return
@@ -295,6 +296,13 @@ public class Proxy implements java.io.Serializable {
     private static final ClassLoaderValue<Constructor<?>> proxyCache =
         new ClassLoaderValue<>();
 
+    /**
+     * System property to revert to generation of proxy class files for version 1.5 (V49).
+     * Set to "true" to generate v49 class file format.
+     */
+    private static final boolean PROXY_GENERATOR_V49 =
+            GetBooleanAction.privilegedGetProperty("jdk.proxy.ProxyGenerator.v49");
+
     /**
      * the invocation handler for this proxy instance.
      * @serial
@@ -531,8 +539,9 @@ public class Proxy implements java.io.Serializable {
             /*
              * Generate the specified proxy class.
              */
-            byte[] proxyClassFile = ProxyGenerator.generateProxyClass(
-                    proxyName, interfaces.toArray(EMPTY_CLASS_ARRAY), accessFlags);
+            byte[] proxyClassFile = PROXY_GENERATOR_V49
+                    ? ProxyGenerator_v49.generateProxyClass(proxyName, interfaces, accessFlags)
+                    : ProxyGenerator.generateProxyClass(loader, proxyName, interfaces, accessFlags);
             try {
                 Class<?> pc = JLA.defineClass(loader, proxyName, proxyClassFile,
                                               null, "__dynamic_proxy__");
@@ -1116,6 +1125,5 @@ public class Proxy implements java.io.Serializable {
         return ih;
     }
 
-    private static final Class<?>[] EMPTY_CLASS_ARRAY = new Class<?>[0];
     private static final String PROXY_PACKAGE_PREFIX = ReflectUtil.PROXY_PACKAGE;
 }