8317356: Fix missing null checks in the ClassFile API

Co-authored-by: Nizar Benalla <nbenalla@openjdk.org>
Reviewed-by: asotona

src/java.base/share/classes/java/lang/classfile/AnnotationValue.java

@@ -42,6 +42,8 @@ import java.util.List;
 import jdk.internal.classfile.impl.Util;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * Models an {@code element_value} structure, or a value of an element-value
  * pair of an annotation, as defined in JVMS {@jvms 4.7.16.1}.
@@ -488,6 +490,8 @@ public sealed interface AnnotationValue {
      */
     static OfEnum ofEnum(Utf8Entry className,
                          Utf8Entry constantName) {
+        requireNonNull(className);
+        requireNonNull(constantName);
         return new AnnotationImpl.OfEnumImpl(className, constantName);
     }
 
@@ -506,6 +510,7 @@ public sealed interface AnnotationValue {
      * @param className the descriptor string of the class
      */
     static OfClass ofClass(Utf8Entry className) {
+        requireNonNull(className);
         return new AnnotationImpl.OfClassImpl(className);
     }
 
@@ -522,6 +527,7 @@ public sealed interface AnnotationValue {
      * @param value the string
      */
     static OfString ofString(Utf8Entry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfStringImpl(value);
     }
 
@@ -538,6 +544,7 @@ public sealed interface AnnotationValue {
      * @param value the double value
      */
     static OfDouble ofDouble(DoubleEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfDoubleImpl(value);
     }
 
@@ -554,6 +561,7 @@ public sealed interface AnnotationValue {
      * @param value the float value
      */
     static OfFloat ofFloat(FloatEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfFloatImpl(value);
     }
 
@@ -570,6 +578,7 @@ public sealed interface AnnotationValue {
      * @param value the long value
      */
     static OfLong ofLong(LongEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfLongImpl(value);
     }
 
@@ -586,6 +595,7 @@ public sealed interface AnnotationValue {
      * @param value the int value
      */
     static OfInt ofInt(IntegerEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfIntImpl(value);
     }
 
@@ -602,6 +612,7 @@ public sealed interface AnnotationValue {
      * @param value the short value
      */
     static OfShort ofShort(IntegerEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfShortImpl(value);
     }
 
@@ -618,6 +629,7 @@ public sealed interface AnnotationValue {
      * @param value the char value
      */
     static OfChar ofChar(IntegerEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfCharImpl(value);
     }
 
@@ -634,6 +646,7 @@ public sealed interface AnnotationValue {
      * @param value the byte value
      */
     static OfByte ofByte(IntegerEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfByteImpl(value);
     }
 
@@ -650,6 +663,7 @@ public sealed interface AnnotationValue {
      * @param value the boolean value
      */
     static OfBoolean ofBoolean(IntegerEntry value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfBooleanImpl(value);
     }
 
@@ -667,6 +681,7 @@ public sealed interface AnnotationValue {
      * @param value the annotation
      */
     static OfAnnotation ofAnnotation(Annotation value) {
+        requireNonNull(value);
         return new AnnotationImpl.OfAnnotationImpl(value);
     }
 
@@ -784,6 +799,6 @@ public sealed interface AnnotationValue {
         } else if (value instanceof Enum<?> e) {
             return ofEnum(ClassDesc.ofDescriptor(e.getDeclaringClass().descriptorString()), e.name());
         }
-        throw new IllegalArgumentException("Illegal annotation constant value type " + (value == null ? null : value.getClass()));
+        throw new IllegalArgumentException("Illegal annotation constant value type " + requireNonNull(value).getClass());
     }
 }

src/java.base/share/classes/java/lang/classfile/AttributedElement.java

@@ -33,6 +33,8 @@ import java.lang.classfile.attribute.RecordComponentInfo;
 import jdk.internal.classfile.impl.AbstractUnboundModel;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * A {@link ClassFileElement} describing an entity that has attributes, such
  * as a class, field, method, code attribute, or record component.
@@ -58,6 +60,7 @@ public sealed interface AttributedElement extends ClassFileElement
      * is not present
      */
     default <T extends Attribute<T>> Optional<T> findAttribute(AttributeMapper<T> attr) {
+        requireNonNull(attr);
         for (Attribute<?> la : attributes()) {
             if (la.attributeMapper() == attr) {
                 @SuppressWarnings("unchecked")
@@ -76,6 +79,7 @@ public sealed interface AttributedElement extends ClassFileElement
      * is not present
      */
     default <T extends Attribute<T>> List<T> findAttributes(AttributeMapper<T> attr) {
+        requireNonNull(attr);
         var list = new ArrayList<T>();
         for (var a : attributes()) {
             if (a.attributeMapper() == attr) {

src/java.base/share/classes/java/lang/classfile/ClassHierarchyResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, 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
@@ -39,6 +39,8 @@ import jdk.internal.classfile.impl.ClassHierarchyImpl.StaticClassHierarchyResolv
 import jdk.internal.classfile.impl.Util;
 
 import static java.lang.constant.ConstantDescs.CD_Object;
+import static java.util.Objects.requireNonNull;
+
 import jdk.internal.javac.PreviewFeature;
 
 /**
@@ -106,6 +108,7 @@ public interface ClassHierarchyResolver {
      *           other resolver in cases where this resolver returns {@code null}.
      */
     default ClassHierarchyResolver orElse(ClassHierarchyResolver other) {
+        requireNonNull(other);
         return new ClassHierarchyResolver() {
             @Override
             public ClassHierarchyInfo getClassInfo(ClassDesc classDesc) {
@@ -170,7 +173,7 @@ public interface ClassHierarchyResolver {
      * @return the {@linkplain ClassHierarchyResolver}
      */
     static ClassHierarchyResolver ofResourceParsing(Function<ClassDesc, InputStream> classStreamResolver) {
-        return new ClassHierarchyImpl.ResourceParsingClassHierarchyResolver(classStreamResolver);
+        return new ClassHierarchyImpl.ResourceParsingClassHierarchyResolver(requireNonNull(classStreamResolver));
     }
 
     /**
@@ -181,6 +184,7 @@ public interface ClassHierarchyResolver {
      * @return the {@linkplain ClassHierarchyResolver}
      */
     static ClassHierarchyResolver ofResourceParsing(ClassLoader loader) {
+        requireNonNull(loader);
         return ofResourceParsing(new Function<>() {
             @Override
             public InputStream apply(ClassDesc classDesc) {
@@ -210,6 +214,7 @@ public interface ClassHierarchyResolver {
      * @return the class hierarchy resolver
      */
     static ClassHierarchyResolver ofClassLoading(ClassLoader loader) {
+        requireNonNull(loader);
         return new ClassLoadingClassHierarchyResolver(new Function<>() {
             @Override
             public Class<?> apply(ClassDesc cd) {
@@ -232,6 +237,7 @@ public interface ClassHierarchyResolver {
      * @return the class hierarchy resolver
      */
     static ClassHierarchyResolver ofClassLoading(MethodHandles.Lookup lookup) {
+        requireNonNull(lookup);
         return new ClassLoadingClassHierarchyResolver(new Function<>() {
             @Override
             public Class<?> apply(ClassDesc cd) {

src/java.base/share/classes/java/lang/classfile/ClassTransform.java

@@ -32,6 +32,8 @@ import java.lang.classfile.attribute.CodeAttribute;
 import jdk.internal.classfile.impl.TransformImpl;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * A transformation on streams of {@link ClassElement}.
  *
@@ -63,7 +65,7 @@ public non-sealed interface ClassTransform
      * @return the stateful class transform
      */
     static ClassTransform ofStateful(Supplier<ClassTransform> supplier) {
-        return new TransformImpl.SupplierClassTransform(supplier);
+        return new TransformImpl.SupplierClassTransform(requireNonNull(supplier));
     }
 
     /**
@@ -74,6 +76,7 @@ public non-sealed interface ClassTransform
      * @return the class transform
      */
     static ClassTransform endHandler(Consumer<ClassBuilder> finisher) {
+        requireNonNull(finisher);
         return new ClassTransform() {
             @Override
             public void accept(ClassBuilder builder, ClassElement element) {
@@ -95,6 +98,7 @@ public non-sealed interface ClassTransform
      * @return the class transform
      */
     static ClassTransform dropping(Predicate<ClassElement> filter) {
+        requireNonNull(filter);
         return (b, e) -> {
             if (!filter.test(e))
                 b.with(e);
@@ -111,7 +115,7 @@ public non-sealed interface ClassTransform
      */
     static ClassTransform transformingMethods(Predicate<MethodModel> filter,
                                               MethodTransform xform) {
-        return new TransformImpl.ClassMethodTransform(xform, filter);
+        return new TransformImpl.ClassMethodTransform(requireNonNull(xform), requireNonNull(filter));
     }
 
     /**
@@ -122,7 +126,7 @@ public non-sealed interface ClassTransform
      * @return the class transform
      */
     static ClassTransform transformingMethods(MethodTransform xform) {
-        return transformingMethods(mm -> true, xform);
+        return transformingMethods(_ -> true, xform);
     }
 
     /**
@@ -157,7 +161,7 @@ public non-sealed interface ClassTransform
      * @return the class transform
      */
     static ClassTransform transformingFields(FieldTransform xform) {
-        return new TransformImpl.ClassFieldTransform(xform, f -> true);
+        return new TransformImpl.ClassFieldTransform(requireNonNull(xform), _ -> true);
     }
 
     /**
@@ -169,6 +173,6 @@ public non-sealed interface ClassTransform
      */
     @Override
     default ClassTransform andThen(ClassTransform t) {
-        return new TransformImpl.ChainedClassTransform(this, t);
+        return new TransformImpl.ChainedClassTransform(this, requireNonNull(t));
     }
 }

src/java.base/share/classes/java/lang/classfile/CodeTransform.java

@@ -30,6 +30,8 @@ import java.util.function.Supplier;
 import jdk.internal.classfile.impl.TransformImpl;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * A transformation on streams of {@link CodeElement}.
  *
@@ -61,7 +63,7 @@ public non-sealed interface CodeTransform
      * @return the stateful code transform
      */
     static CodeTransform ofStateful(Supplier<CodeTransform> supplier) {
-        return new TransformImpl.SupplierCodeTransform(supplier);
+        return new TransformImpl.SupplierCodeTransform(requireNonNull(supplier));
     }
 
     /**
@@ -72,6 +74,7 @@ public non-sealed interface CodeTransform
      * @return the code transform
      */
     static CodeTransform endHandler(Consumer<CodeBuilder> finisher) {
+        requireNonNull(finisher);
         return new CodeTransform() {
             @Override
             public void accept(CodeBuilder builder, CodeElement element) {
@@ -94,6 +97,6 @@ public non-sealed interface CodeTransform
      */
     @Override
     default CodeTransform andThen(CodeTransform t) {
-        return new TransformImpl.ChainedCodeTransform(this, t);
+        return new TransformImpl.ChainedCodeTransform(this, requireNonNull(t));
     }
 }

src/java.base/share/classes/java/lang/classfile/FieldTransform.java

@@ -31,6 +31,8 @@ import java.util.function.Supplier;
 import jdk.internal.classfile.impl.TransformImpl;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * A transformation on streams of {@link FieldElement}.
  *
@@ -62,7 +64,7 @@ public non-sealed interface FieldTransform
      * @return the stateful field transform
      */
     static FieldTransform ofStateful(Supplier<FieldTransform> supplier) {
-        return new TransformImpl.SupplierFieldTransform(supplier);
+        return new TransformImpl.SupplierFieldTransform(requireNonNull(supplier));
     }
 
     /**
@@ -73,6 +75,7 @@ public non-sealed interface FieldTransform
      * @return the field transform
      */
     static FieldTransform endHandler(Consumer<FieldBuilder> finisher) {
+        requireNonNull(finisher);
         return new FieldTransform() {
             @Override
             public void accept(FieldBuilder builder, FieldElement element) {
@@ -94,6 +97,7 @@ public non-sealed interface FieldTransform
      * @return the field transform
      */
     static FieldTransform dropping(Predicate<FieldElement> filter) {
+        requireNonNull(filter);
         return (b, e) -> {
             if (!filter.test(e))
                 b.with(e);
@@ -109,6 +113,6 @@ public non-sealed interface FieldTransform
      */
     @Override
     default FieldTransform andThen(FieldTransform t) {
-        return new TransformImpl.ChainedFieldTransform(this, t);
+        return new TransformImpl.ChainedFieldTransform(this, requireNonNull(t));
     }
 }

src/java.base/share/classes/java/lang/classfile/MethodTransform.java

@@ -31,6 +31,8 @@ import java.util.function.Supplier;
 import jdk.internal.classfile.impl.TransformImpl;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * A transformation on streams of {@link MethodElement}.
  *
@@ -62,6 +64,7 @@ public non-sealed interface MethodTransform
      * @return the stateful method transform
      */
     static MethodTransform ofStateful(Supplier<MethodTransform> supplier) {
+        requireNonNull(supplier);
         return new TransformImpl.SupplierMethodTransform(supplier);
     }
 
@@ -73,6 +76,7 @@ public non-sealed interface MethodTransform
      * @return the method transform
      */
     static MethodTransform endHandler(Consumer<MethodBuilder> finisher) {
+        requireNonNull(finisher);
         return new MethodTransform() {
             @Override
             public void accept(MethodBuilder builder, MethodElement element) {
@@ -94,6 +98,7 @@ public non-sealed interface MethodTransform
      * @return the method transform
      */
     static MethodTransform dropping(Predicate<MethodElement> filter) {
+        requireNonNull(filter);
         return (b, e) -> {
             if (!filter.test(e))
                 b.with(e);
@@ -108,7 +113,7 @@ public non-sealed interface MethodTransform
      * @return the class transform
      */
     static MethodTransform transformingCode(CodeTransform xform) {
-        return new TransformImpl.MethodCodeTransform(xform);
+        return new TransformImpl.MethodCodeTransform(requireNonNull(xform));
     }
 
     /**
@@ -120,6 +125,6 @@ public non-sealed interface MethodTransform
      */
     @Override
     default MethodTransform andThen(MethodTransform t) {
-        return new TransformImpl.ChainedMethodTransform(this, t);
+        return new TransformImpl.ChainedMethodTransform(this, requireNonNull(t));
     }
 }

src/java.base/share/classes/java/lang/classfile/components/ClassRemapper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, 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
@@ -36,6 +36,8 @@ import java.lang.classfile.MethodTransform;
 import jdk.internal.classfile.impl.ClassRemapperImpl;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * {@code ClassRemapper} is a {@link ClassTransform}, {@link FieldTransform},
  * {@link MethodTransform} and {@link CodeTransform}
@@ -64,6 +66,7 @@ public sealed interface ClassRemapper extends ClassTransform permits ClassRemapp
      * @return new instance of {@code ClassRemapper}
      */
     static ClassRemapper of(Map<ClassDesc, ClassDesc> classMap) {
+        requireNonNull(classMap);
         return of(desc -> classMap.getOrDefault(desc, desc));
     }
 
@@ -75,7 +78,7 @@ public sealed interface ClassRemapper extends ClassTransform permits ClassRemapp
      * @return new instance of {@code ClassRemapper}
      */
     static ClassRemapper of(Function<ClassDesc, ClassDesc> mapFunction) {
-        return new ClassRemapperImpl(mapFunction);
+        return new ClassRemapperImpl(requireNonNull(mapFunction));
     }
 
     /**

src/java.base/share/classes/java/lang/classfile/components/CodeRelabeler.java

@@ -33,6 +33,8 @@ import java.lang.classfile.Label;
 import jdk.internal.classfile.impl.CodeRelabelerImpl;
 import jdk.internal.javac.PreviewFeature;
 
+import static java.util.Objects.requireNonNull;
+
 /**
  * A code relabeler is a {@link CodeTransform} replacing all occurrences
  * of {@link java.lang.classfile.Label} in the transformed code with new instances.
@@ -62,6 +64,7 @@ public sealed interface CodeRelabeler extends CodeTransform permits CodeRelabele
      * @return a new instance of CodeRelabeler
      */
     static CodeRelabeler of(Map<Label, Label> map) {
+        requireNonNull(map);
         return of((l, cob) -> map.computeIfAbsent(l, ll -> cob.newLabel()));
     }
 
@@ -72,6 +75,6 @@ public sealed interface CodeRelabeler extends CodeTransform permits CodeRelabele
      * @return a new instance of CodeRelabeler
      */
     static CodeRelabeler of(BiFunction<Label, CodeBuilder, Label> mapFunction) {
-        return new CodeRelabelerImpl(mapFunction);
+        return new CodeRelabelerImpl(requireNonNull(mapFunction));
     }
 }

src/java.base/share/classes/java/lang/classfile/instruction/DiscontinuedInstruction.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2023, 2024, 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

src/java.base/share/classes/java/lang/invoke/MethodHandleProxies.java

@@ -54,6 +54,7 @@ import java.lang.classfile.CodeBuilder;
 import java.lang.classfile.TypeKind;
 
 import jdk.internal.constant.ConstantUtils;
+import jdk.internal.loader.ClassLoaders;
 import jdk.internal.module.Modules;
 import jdk.internal.reflect.CallerSensitive;
 import jdk.internal.reflect.Reflection;
@@ -371,7 +372,8 @@ public class MethodHandleProxies {
      */
     private static byte[] createTemplate(ClassLoader loader, ClassDesc proxyDesc, ClassDesc ifaceDesc,
                                          String methodName, List<MethodInfo> methods) {
-        return ClassFile.of(ClassHierarchyResolverOption.of(ClassHierarchyResolver.ofClassLoading(loader)))
+        return ClassFile.of(ClassHierarchyResolverOption.of(ClassHierarchyResolver.ofClassLoading(loader == null ?
+                        ClassLoaders.platformClassLoader() : loader)))
                         .build(proxyDesc, clb -> {
             clb.withSuperclass(CD_Object)
                .withFlags(ACC_FINAL | ACC_SYNTHETIC)

src/java.base/share/classes/jdk/internal/classfile/impl/AbstractInstruction.java

@@ -66,6 +66,8 @@ import java.lang.classfile.Label;
 import java.lang.classfile.Opcode;
 import java.lang.classfile.TypeKind;
 
+import static java.util.Objects.requireNonNull;
+
 public abstract sealed class AbstractInstruction
         extends AbstractElement
         implements Instruction {
@@ -247,6 +249,9 @@ public abstract sealed class AbstractInstruction
 
     public record SwitchCaseImpl(int caseValue, Label target)
             implements SwitchCase {
+        public SwitchCaseImpl {
+            requireNonNull(target);
+        }
     }
 
     public static final class BoundLookupSwitchInstruction
@@ -892,7 +897,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundBranchInstruction(Opcode op, Label target) {
             super(op);
-            this.target = target;
+            this.target = requireNonNull(target);
         }
 
         @Override
@@ -919,7 +924,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundLookupSwitchInstruction(Label defaultTarget, List<SwitchCase> cases) {
             super(Opcode.LOOKUPSWITCH);
-            this.defaultTarget = defaultTarget;
+            this.defaultTarget = requireNonNull(defaultTarget);
             this.cases = List.copyOf(cases);
         }
 
@@ -955,7 +960,7 @@ public abstract sealed class AbstractInstruction
             super(Opcode.TABLESWITCH);
             this.lowValue = lowValue;
             this.highValue = highValue;
-            this.defaultTarget = defaultTarget;
+            this.defaultTarget = requireNonNull(defaultTarget);
             this.cases = List.copyOf(cases);
         }
 
@@ -1030,7 +1035,7 @@ public abstract sealed class AbstractInstruction
         public UnboundFieldInstruction(Opcode op,
                                        FieldRefEntry fieldEntry) {
             super(op);
-            this.fieldEntry = fieldEntry;
+            this.fieldEntry = requireNonNull(fieldEntry);
         }
 
         @Override
@@ -1055,7 +1060,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundInvokeInstruction(Opcode op, MemberRefEntry methodEntry) {
             super(op);
-            this.methodEntry = methodEntry;
+            this.methodEntry = requireNonNull(methodEntry);
         }
 
         @Override
@@ -1095,7 +1100,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundInvokeDynamicInstruction(InvokeDynamicEntry indyEntry) {
             super(Opcode.INVOKEDYNAMIC);
-            this.indyEntry = indyEntry;
+            this.indyEntry = requireNonNull(indyEntry);
         }
 
         @Override
@@ -1120,7 +1125,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundNewObjectInstruction(ClassEntry classEntry) {
             super(Opcode.NEW);
-            this.classEntry = classEntry;
+            this.classEntry = requireNonNull(classEntry);
         }
 
         @Override
@@ -1145,7 +1150,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundNewPrimitiveArrayInstruction(TypeKind typeKind) {
             super(Opcode.NEWARRAY);
-            this.typeKind = typeKind;
+            this.typeKind = requireNonNull(typeKind);
         }
 
         @Override
@@ -1170,7 +1175,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundNewReferenceArrayInstruction(ClassEntry componentTypeEntry) {
             super(Opcode.ANEWARRAY);
-            this.componentTypeEntry = componentTypeEntry;
+            this.componentTypeEntry = requireNonNull(componentTypeEntry);
         }
 
         @Override
@@ -1197,7 +1202,7 @@ public abstract sealed class AbstractInstruction
         public UnboundNewMultidimensionalArrayInstruction(ClassEntry arrayTypeEntry,
                                                           int dimensions) {
             super(Opcode.MULTIANEWARRAY);
-            this.arrayTypeEntry = arrayTypeEntry;
+            this.arrayTypeEntry = requireNonNull(arrayTypeEntry);
             this.dimensions = dimensions;
         }
 
@@ -1255,7 +1260,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundTypeCheckInstruction(Opcode op, ClassEntry typeEntry) {
             super(op);
-            this.typeEntry = typeEntry;
+            this.typeEntry = requireNonNull(typeEntry);
         }
 
         @Override
@@ -1357,7 +1362,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundLoadConstantInstruction(Opcode op, LoadableConstantEntry constant) {
             super(op);
-            this.constant = constant;
+            this.constant = requireNonNull(constant);
         }
 
         @Override
@@ -1405,7 +1410,7 @@ public abstract sealed class AbstractInstruction
 
         public UnboundJsrInstruction(Opcode op, Label target) {
             super(op);
-            this.target = target;
+            this.target = requireNonNull(target);
         }
 
         @Override

src/java.base/share/classes/jdk/internal/classfile/impl/AbstractPoolEntry.java

@@ -56,6 +56,8 @@ import jdk.internal.access.SharedSecrets;
 import jdk.internal.util.ArraysSupport;
 import jdk.internal.vm.annotation.Stable;
 
+import static java.util.Objects.requireNonNull;
+
 public abstract sealed class AbstractPoolEntry {
     /*
     Invariant: a {CP,BSM} entry for pool P refer only to {CP,BSM} entries
@@ -439,7 +441,7 @@ public abstract sealed class AbstractPoolEntry {
                 inflate();
             switch (state) {
                 case STRING:
-                    return stringValue.equals(s);
+                    return stringValue.equals(requireNonNull(s));
                 case CHAR:
                     if (charLen != s.length() || contentHash != s.hashCode())
                         return false;

src/java.base/share/classes/jdk/internal/classfile/impl/AbstractPseudoInstruction.java

@@ -36,6 +36,8 @@ import java.lang.classfile.instruction.LocalVariableType;
 import java.lang.classfile.Label;
 import java.lang.classfile.PseudoInstruction;
 
+import static java.util.Objects.requireNonNull;
+
 public abstract sealed class AbstractPseudoInstruction
         extends AbstractElement
         implements PseudoInstruction {
@@ -55,17 +57,14 @@ public abstract sealed class AbstractPseudoInstruction
         public ExceptionCatchImpl(Label handler, Label tryStart, Label tryEnd,
                                   ClassEntry catchTypeEntry) {
             this.catchTypeEntry = catchTypeEntry;
-            this.handler = handler;
+            this.handler = requireNonNull(handler);
-            this.tryStart = tryStart;
+            this.tryStart = requireNonNull(tryStart);
-            this.tryEnd = tryEnd;
+            this.tryEnd = requireNonNull(tryEnd);
         }
 
         public ExceptionCatchImpl(Label handler, Label tryStart, Label tryEnd,
                                   Optional<ClassEntry> catchTypeEntry) {
-            this.catchTypeEntry = catchTypeEntry.orElse(null);
+            this(handler, tryStart, tryEnd, catchTypeEntry.orElse(null));
-            this.handler = handler;
-            this.tryStart = tryStart;
-            this.tryEnd = tryEnd;
         }
 
         @Override
@@ -115,8 +114,8 @@ public abstract sealed class AbstractPseudoInstruction
 
         public UnboundCharacterRange(Label startScope, Label endScope, int characterRangeStart,
                                      int characterRangeEnd, int flags) {
-            this.startScope = startScope;
+            this.startScope = requireNonNull(startScope);
-            this.endScope = endScope;
+            this.endScope = requireNonNull(endScope);
             this.characterRangeStart = characterRangeStart;
             this.characterRangeEnd = characterRangeEnd;
             this.flags = flags;
@@ -165,10 +164,10 @@ public abstract sealed class AbstractPseudoInstruction
         public AbstractLocalPseudo(int slot, Utf8Entry name, Utf8Entry descriptor, Label startScope, Label endScope) {
             BytecodeHelpers.validateSlot(slot);
             this.slot = slot;
-            this.name = name;
+            this.name = requireNonNull(name);
-            this.descriptor = descriptor;
+            this.descriptor = requireNonNull(descriptor);
-            this.startScope = startScope;
+            this.startScope = requireNonNull(startScope);
-            this.endScope = endScope;
+            this.endScope = requireNonNull(endScope);
         }
 
         public int slot() {

src/java.base/share/classes/jdk/internal/classfile/impl/AnnotationImpl.java

@@ -29,9 +29,12 @@ import java.lang.classfile.constantpool.*;
 
 import java.util.List;
 
+import static java.util.Objects.requireNonNull;
+
 public record AnnotationImpl(Utf8Entry className, List<AnnotationElement> elements)
         implements Annotation {
     public AnnotationImpl {
+        requireNonNull(className);
         elements = List.copyOf(elements);
     }
 
@@ -50,6 +53,11 @@ public record AnnotationImpl(Utf8Entry className, List<AnnotationElement> elemen
     public record AnnotationElementImpl(Utf8Entry name,
                                         AnnotationValue value)
             implements AnnotationElement {
+        public AnnotationElementImpl {
+            requireNonNull(name);
+            requireNonNull(value);
+        }
+
         @Override
         public String toString() {
             return name + "=" + value;

src/java.base/share/classes/jdk/internal/classfile/impl/BlockCodeBuilderImpl.java

@@ -33,6 +33,8 @@ import java.lang.classfile.instruction.LabelTarget;
 import java.util.Objects;
 import java.lang.classfile.Instruction;
 
+import static java.util.Objects.requireNonNull;
+
 public final class BlockCodeBuilderImpl
         extends NonterminalCodeBuilder
         implements CodeBuilder.BlockCodeBuilder {
@@ -80,7 +82,7 @@ public final class BlockCodeBuilderImpl
 
     @Override
     public CodeBuilder with(CodeElement element) {
-        parent.with(element);
+        parent.with(requireNonNull(element));
 
         hasInstructions |= element instanceof Instruction;
 

src/java.base/share/classes/jdk/internal/classfile/impl/BufferedCodeBuilder.java

@@ -38,6 +38,8 @@ import java.util.List;
 import java.util.Optional;
 import java.util.function.Consumer;
 
+import static java.util.Objects.requireNonNull;
+
 public final class BufferedCodeBuilder
         implements TerminalCodeBuilder {
     private final SplitConstantPool constantPool;
@@ -121,7 +123,7 @@ public final class BufferedCodeBuilder
     public CodeBuilder with(CodeElement element) {
         if (finished)
             throw new IllegalStateException("Can't add elements after traversal");
-        elements.add(element);
+        elements.add(requireNonNull(element));
         return this;
     }
 

src/java.base/share/classes/jdk/internal/classfile/impl/BufferedFieldBuilder.java

@@ -34,6 +34,8 @@ import java.lang.classfile.*;
 import java.lang.classfile.constantpool.ConstantPoolBuilder;
 import java.lang.classfile.constantpool.Utf8Entry;
 
+import static java.util.Objects.requireNonNull;
+
 public final class BufferedFieldBuilder
         implements TerminalFieldBuilder {
     private final SplitConstantPool constantPool;
@@ -49,8 +51,8 @@ public final class BufferedFieldBuilder
                                 Utf8Entry type) {
         this.constantPool = constantPool;
         this.context = context;
-        this.name = name;
+        this.name = requireNonNull(name);
-        this.desc = type;
+        this.desc = requireNonNull(type);
         this.flags = new AccessFlagsImpl(AccessFlag.Location.FIELD);
     }
 
@@ -61,7 +63,7 @@ public final class BufferedFieldBuilder
 
     @Override
     public FieldBuilder with(FieldElement element) {
-        elements.add(element);
+        elements.add(requireNonNull(element));
         if (element instanceof AccessFlags f) this.flags = f;
         return this;
     }

src/java.base/share/classes/jdk/internal/classfile/impl/BufferedMethodBuilder.java

@@ -43,6 +43,8 @@ import java.lang.classfile.MethodElement;
 import java.lang.classfile.MethodModel;
 import java.lang.classfile.constantpool.Utf8Entry;
 
+import static java.util.Objects.requireNonNull;
+
 public final class BufferedMethodBuilder
         implements TerminalMethodBuilder {
     private final List<MethodElement> elements;
@@ -63,15 +65,15 @@ public final class BufferedMethodBuilder
         this.elements = new ArrayList<>();
         this.constantPool = constantPool;
         this.context = context;
-        this.name = nameInfo;
+        this.name = requireNonNull(nameInfo);
-        this.desc = typeInfo;
+        this.desc = requireNonNull(typeInfo);
         this.flags = new AccessFlagsImpl(AccessFlag.Location.METHOD, flags);
         this.original = original;
     }
 
     @Override
     public MethodBuilder with(MethodElement element) {
-        elements.add(element);
+        elements.add(requireNonNull(element));
         if (element instanceof AccessFlags f) this.flags = checkFlags(f);
         return this;
     }

src/java.base/share/classes/jdk/internal/classfile/impl/BytecodeHelpers.java

@@ -47,6 +47,7 @@ import java.lang.classfile.constantpool.MethodHandleEntry;
 import java.lang.classfile.constantpool.NameAndTypeEntry;
 import java.util.Objects;
 
+import static java.util.Objects.requireNonNull;
 import static jdk.internal.classfile.impl.RawBytecodeHelper.*;
 
 /**
@@ -463,7 +464,7 @@ public class BytecodeHelpers {
         if (opcode == Opcode.RET && (slot & ~0xFF) == 0 ||
                 opcode == Opcode.RET_W && (slot & ~0xFFFF) == 0)
             return;
-        Objects.requireNonNull(opcode);
+        requireNonNull(opcode);
         throw slotOutOfBounds(opcode, slot);
     }
 
@@ -551,7 +552,7 @@ public class BytecodeHelpers {
         } if (constantValue instanceof DynamicConstantDesc<?> value) {
             return handleConstantDescToHandleInfo(constantPool, value);
         }
-        throw new UnsupportedOperationException("not yet: " + constantValue);
+        throw new UnsupportedOperationException("not yet: " + requireNonNull(constantValue));
     }
 
     public static ConstantDesc intrinsicConstantValue(Opcode opcode) {

src/java.base/share/classes/jdk/internal/classfile/impl/ChainedClassBuilder.java

@@ -31,6 +31,8 @@ import java.lang.classfile.*;
 import java.lang.classfile.constantpool.ConstantPoolBuilder;
 import java.lang.classfile.constantpool.Utf8Entry;
 
+import static java.util.Objects.requireNonNull;
+
 public final class ChainedClassBuilder
         implements ClassBuilder, Consumer<ClassElement> {
     private final DirectClassBuilder terminal;
@@ -47,7 +49,7 @@ public final class ChainedClassBuilder
 
     @Override
     public ClassBuilder with(ClassElement element) {
-        consumer.accept(element);
+        consumer.accept(requireNonNull(element));
         return this;
     }
 

src/java.base/share/classes/jdk/internal/classfile/impl/ChainedCodeBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, 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
@@ -31,6 +31,8 @@ import java.lang.classfile.Label;
 
 import java.util.function.Consumer;
 
+import static java.util.Objects.requireNonNull;
+
 public final class ChainedCodeBuilder
         extends NonterminalCodeBuilder
         implements CodeBuilder {
@@ -59,7 +61,7 @@ public final class ChainedCodeBuilder
 
     @Override
     public CodeBuilder with(CodeElement element) {
-        consumer.accept(element);
+        consumer.accept(requireNonNull(element));
         return this;
     }
 }

src/java.base/share/classes/jdk/internal/classfile/impl/ChainedFieldBuilder.java

@@ -30,6 +30,8 @@ import java.lang.classfile.FieldBuilder;
 import java.lang.classfile.FieldElement;
 import java.lang.classfile.constantpool.ConstantPoolBuilder;
 
+import static java.util.Objects.requireNonNull;
+
 public final class ChainedFieldBuilder implements FieldBuilder {
     private final TerminalFieldBuilder terminal;
     private final Consumer<FieldElement> consumer;
@@ -50,7 +52,7 @@ public final class ChainedFieldBuilder implements FieldBuilder {
 
     @Override
     public FieldBuilder with(FieldElement element) {
-        consumer.accept(element);
+        consumer.accept(requireNonNull(element));
         return this;
     }
 

src/java.base/share/classes/jdk/internal/classfile/impl/ChainedMethodBuilder.java

@@ -33,6 +33,8 @@ import java.lang.classfile.MethodBuilder;
 import java.lang.classfile.MethodElement;
 import java.lang.classfile.constantpool.ConstantPoolBuilder;
 
+import static java.util.Objects.requireNonNull;
+
 public final class ChainedMethodBuilder implements MethodBuilder {
     final TerminalMethodBuilder terminal;
     final Consumer<MethodElement> consumer;
@@ -48,7 +50,7 @@ public final class ChainedMethodBuilder implements MethodBuilder {
 
     @Override
     public MethodBuilder with(MethodElement element) {
-        consumer.accept(element);
+        consumer.accept(requireNonNull(element));
         return this;
     }
 

src/java.base/share/classes/jdk/internal/classfile/impl/ClassFileImpl.java

@@ -40,6 +40,8 @@ import java.lang.classfile.constantpool.ConstantPoolBuilder;
 import java.lang.classfile.constantpool.Utf8Entry;
 import jdk.internal.classfile.impl.verifier.VerifierImpl;
 
+import static java.util.Objects.requireNonNull;
+
 public final class ClassFileImpl implements ClassFile {
 
     private Option stackMapsOption;
@@ -123,7 +125,7 @@ public final class ClassFileImpl implements ClassFile {
             } else if (o instanceof AttributeMapperOption oo) {
                 amo = oo;
             } else { // null or unknown Option type
-                throw new IllegalArgumentException("Invalid option: " + o);
+                throw new IllegalArgumentException("Invalid option: " + requireNonNull(o));
             }
         }
         return new ClassFileImpl(smo, deo, lno, apo, cpso, sjo, dco, dlo, chro, amo);

src/java.base/share/classes/jdk/internal/classfile/impl/ClassHierarchyImpl.java

@@ -205,9 +205,9 @@ public final class ClassHierarchyImpl {
             map = HashMap.newHashMap(interfaceNames.size() + classToSuperClass.size() + 1);
             map.put(CD_Object, ClassHierarchyInfoImpl.OBJECT_INFO);
             for (var e : classToSuperClass.entrySet())
-                map.put(e.getKey(), ClassHierarchyInfo.ofClass(e.getValue()));
+                map.put(requireNonNull(e.getKey()), ClassHierarchyInfo.ofClass(e.getValue()));
             for (var i : interfaceNames)
-                map.put(i, ClassHierarchyInfo.ofInterface());
+                map.put(requireNonNull(i), ClassHierarchyInfo.ofInterface());
         }
 
         @Override

src/java.base/share/classes/jdk/internal/classfile/impl/ClassPrinterImpl.java

@@ -61,6 +61,7 @@ import java.lang.classfile.instruction.*;
 import java.lang.classfile.CompoundElement;
 import java.lang.classfile.FieldModel;
 import static java.lang.classfile.constantpool.PoolEntry.*;
+import static java.util.Objects.requireNonNull;
 import static jdk.internal.classfile.impl.ClassPrinterImpl.Style.*;
 
 public final class ClassPrinterImpl {
@@ -564,6 +565,7 @@ public final class ClassPrinterImpl {
     private record ExceptionHandler(int start, int end, int handler, String catchType) {}
 
     public static MapNode modelToTree(CompoundElement<?> model, Verbosity verbosity) {
+        requireNonNull(verbosity); // we are using == checks in implementations
         return switch(model) {
             case ClassModel cm -> classToTree(cm, verbosity);
             case FieldModel fm -> fieldToTree(fm, verbosity);

src/java.base/share/classes/jdk/internal/classfile/impl/DirectClassBuilder.java

@@ -26,11 +26,7 @@
 
 package jdk.internal.classfile.impl;
 
-import java.lang.constant.ClassDesc;
 import java.lang.constant.ConstantDescs;
-import java.lang.constant.MethodTypeDesc;
-import java.lang.reflect.AccessFlag;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -50,6 +46,8 @@ import java.lang.classfile.MethodModel;
 import java.lang.classfile.MethodTransform;
 import java.lang.classfile.constantpool.Utf8Entry;
 
+import static java.util.Objects.requireNonNull;
+
 public final class DirectClassBuilder
         extends AbstractDirectBuilder<ClassModel>
         implements ClassBuilder {
@@ -87,7 +85,7 @@ public final class DirectClassBuilder
         if (element instanceof AbstractElement ae) {
             ae.writeTo(this);
         } else {
-            writeAttribute((CustomAttribute<?>) element);
+            writeAttribute((CustomAttribute<?>) requireNonNull(element));
         }
         return this;
     }

src/java.base/share/classes/jdk/internal/classfile/impl/DirectCodeBuilder.java

@@ -64,6 +64,7 @@ import java.util.Map;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
+import static java.util.Objects.requireNonNull;
 import static jdk.internal.classfile.impl.BytecodeHelpers.*;
 import static jdk.internal.classfile.impl.RawBytecodeHelper.*;
 
@@ -147,7 +148,7 @@ public final class DirectCodeBuilder
         if (element instanceof AbstractElement ae) {
             ae.writeTo(this);
         } else {
-            writeAttribute((CustomAttribute<?>) element);
+            writeAttribute((CustomAttribute<?>) requireNonNull(element));
         }
         return this;
     }

src/java.base/share/classes/jdk/internal/classfile/impl/DirectFieldBuilder.java

@@ -33,6 +33,8 @@ import java.lang.classfile.FieldElement;
 import java.lang.classfile.FieldModel;
 import java.lang.classfile.constantpool.Utf8Entry;
 
+import static java.util.Objects.requireNonNull;
+
 public final class DirectFieldBuilder
         extends AbstractDirectBuilder<FieldModel>
         implements TerminalFieldBuilder, Util.Writable {
@@ -48,8 +50,8 @@ public final class DirectFieldBuilder
                               FieldModel original) {
         super(constantPool, context);
         setOriginal(original);
-        this.name = name;
+        this.name = requireNonNull(name);
-        this.desc = type;
+        this.desc = requireNonNull(type);
         this.flags = flags;
     }
 
@@ -58,7 +60,7 @@ public final class DirectFieldBuilder
         if (element instanceof AbstractElement ae) {
             ae.writeTo(this);
         } else {
-            writeAttribute((CustomAttribute<?>) element);
+            writeAttribute((CustomAttribute<?>) requireNonNull(element));
         }
         return this;
     }

src/java.base/share/classes/jdk/internal/classfile/impl/DirectMethodBuilder.java

@@ -38,6 +38,8 @@ import java.lang.classfile.MethodElement;
 import java.lang.classfile.MethodModel;
 import java.lang.classfile.constantpool.Utf8Entry;
 
+import static java.util.Objects.requireNonNull;
+
 public final class DirectMethodBuilder
         extends AbstractDirectBuilder<MethodModel>
         implements TerminalMethodBuilder, Util.Writable {
@@ -55,8 +57,8 @@ public final class DirectMethodBuilder
                                MethodModel original) {
         super(constantPool, context);
         setOriginal(original);
-        this.name = nameInfo;
+        this.name = requireNonNull(nameInfo);
-        this.desc = typeInfo;
+        this.desc = requireNonNull(typeInfo);
         this.flags = flags;
     }
 
@@ -114,7 +116,7 @@ public final class DirectMethodBuilder
         if (element instanceof AbstractElement ae) {
             ae.writeTo(this);
         } else {
-            writeAttribute((CustomAttribute<?>) element);
+            writeAttribute((CustomAttribute<?>) requireNonNull(element));
         }
         return this;
     }

src/java.base/share/classes/jdk/internal/classfile/impl/SplitConstantPool.java

@@ -38,6 +38,7 @@ import java.lang.classfile.constantpool.*;
 import jdk.internal.constant.ConstantUtils;
 
 import static java.lang.classfile.constantpool.PoolEntry.*;
+import static java.util.Objects.requireNonNull;
 
 public final class SplitConstantPool implements ConstantPoolBuilder {
 
@@ -122,6 +123,7 @@ public final class SplitConstantPool implements ConstantPoolBuilder {
 
     @Override
     public boolean canWriteDirect(ConstantPool other) {
+        requireNonNull(other);
         return this == other || parent == other;
     }
 

src/java.base/share/classes/jdk/internal/classfile/impl/StackMapDecoder.java

@@ -42,6 +42,7 @@ import java.util.Objects;
 
 import static java.lang.classfile.ClassFile.*;
 import static java.lang.classfile.attribute.StackMapFrameInfo.VerificationTypeInfo.*;
+import static java.util.Objects.requireNonNull;
 
 public class StackMapDecoder {
 
@@ -245,6 +246,9 @@ public class StackMapDecoder {
 
     public static record ObjectVerificationTypeInfoImpl(
             ClassEntry className) implements ObjectVerificationTypeInfo {
+        public ObjectVerificationTypeInfoImpl {
+            requireNonNull(className);
+        }
 
         @Override
         public int tag() { return ITEM_OBJECT; }
@@ -270,6 +274,9 @@ public class StackMapDecoder {
     }
 
     public static record UninitializedVerificationTypeInfoImpl(Label newTarget) implements UninitializedVerificationTypeInfo {
+        public UninitializedVerificationTypeInfoImpl {
+            requireNonNull(newTarget);
+        }
 
         @Override
         public int tag() { return ITEM_UNINITIALIZED; }
@@ -292,6 +299,7 @@ public class StackMapDecoder {
                                            List<VerificationTypeInfo> stack)
             implements StackMapFrameInfo {
         public StackMapFrameImpl {
+            requireNonNull(target);
             locals = List.copyOf(locals);
             stack = List.copyOf(stack);
         }

src/java.base/share/classes/jdk/internal/classfile/impl/TargetInfoImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2022, 2024, 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
@@ -25,7 +25,6 @@
 package jdk.internal.classfile.impl;
 
 import java.util.List;
-import java.util.Objects;
 import java.lang.classfile.Label;
 import java.lang.classfile.TypeAnnotation.*;
 
@@ -37,7 +36,6 @@ public final class TargetInfoImpl {
     }
 
     private static TargetType checkValid(TargetType targetType, int rangeFrom, int rangeTo) {
-        Objects.requireNonNull(targetType);
         if (targetType.targetTypeValue() < rangeFrom || targetType.targetTypeValue() > rangeTo)
             throw new IllegalArgumentException("Wrong target type specified " + targetType);
         return targetType;

src/java.base/share/classes/jdk/internal/classfile/impl/TemporaryConstantPool.java

@@ -50,6 +50,7 @@ import java.lang.classfile.constantpool.Utf8Entry;
 
 import java.lang.constant.MethodTypeDesc;
 import java.util.List;
+import java.util.Objects;
 
 public final class TemporaryConstantPool implements ConstantPoolBuilder {
 
@@ -187,6 +188,7 @@ public final class TemporaryConstantPool implements ConstantPoolBuilder {
 
     @Override
     public boolean canWriteDirect(ConstantPool constantPool) {
+        Objects.requireNonNull(constantPool);
         return false;
     }
 }

src/java.base/share/classes/jdk/internal/classfile/impl/UnboundAttribute.java

@@ -92,6 +92,8 @@ import java.lang.classfile.constantpool.Utf8Entry;
 
 import jdk.internal.access.SharedSecrets;
 
+import static java.util.Objects.requireNonNull;
+
 public abstract sealed class UnboundAttribute<T extends Attribute<T>>
         extends AbstractElement
         implements Attribute<T>, Util.Writable {
@@ -149,7 +151,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundConstantValueAttribute(ConstantValueEntry entry) {
             super(Attributes.constantValue());
-            this.entry = entry;
+            this.entry = requireNonNull(entry);
         }
 
         @Override
@@ -182,7 +184,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundSignatureAttribute(Utf8Entry signature) {
             super(Attributes.signature());
-            this.signature = signature;
+            this.signature = requireNonNull(signature);
         }
 
         @Override
@@ -214,7 +216,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundAnnotationDefaultAttribute(AnnotationValue annotationDefault) {
             super(Attributes.annotationDefault());
-            this.annotationDefault = annotationDefault;
+            this.annotationDefault = requireNonNull(annotationDefault);
         }
 
         @Override
@@ -229,7 +231,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundSourceFileAttribute(Utf8Entry sourceFile) {
             super(Attributes.sourceFile());
-            this.sourceFile = sourceFile;
+            this.sourceFile = requireNonNull(sourceFile);
         }
 
         @Override
@@ -294,7 +296,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundEnclosingMethodAttribute(ClassEntry classEntry, NameAndTypeEntry method) {
             super(Attributes.enclosingMethod());
-            this.classEntry = classEntry;
+            this.classEntry = requireNonNull(classEntry);
             this.method = method;
         }
 
@@ -332,7 +334,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundModuleTargetAttribute(Utf8Entry moduleTarget) {
             super(Attributes.moduleTarget());
-            this.moduleTarget = moduleTarget;
+            this.moduleTarget = requireNonNull(moduleTarget);
         }
 
         @Override
@@ -348,7 +350,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundModuleMainClassAttribute(ClassEntry mainClass) {
             super(Attributes.moduleMainClass());
-            this.mainClass = mainClass;
+            this.mainClass = requireNonNull(mainClass);
         }
 
         @Override
@@ -365,7 +367,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundModuleHashesAttribute(Utf8Entry algorithm, List<ModuleHashInfo> hashes) {
             super(Attributes.moduleHashes());
-            this.algorithm = algorithm;
+            this.algorithm = requireNonNull(algorithm);
             this.hashes = List.copyOf(hashes);
         }
 
@@ -451,7 +453,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundNestHostAttribute(ClassEntry hostEntry) {
             super(Attributes.nestHost());
-            this.hostEntry = hostEntry;
+            this.hostEntry = requireNonNull(hostEntry);
         }
 
         @Override
@@ -467,7 +469,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundCompilationIDAttribute(Utf8Entry idEntry) {
             super(Attributes.compilationId());
-            this.idEntry = idEntry;
+            this.idEntry = requireNonNull(idEntry);
         }
 
         @Override
@@ -483,7 +485,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundSourceIDAttribute(Utf8Entry idEntry) {
             super(Attributes.sourceId());
-            this.idEntry = idEntry;
+            this.idEntry = requireNonNull(idEntry);
         }
 
         @Override
@@ -499,7 +501,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundSourceDebugExtensionAttribute(byte[] contents) {
             super(Attributes.sourceDebugExtension());
-            this.contents = contents;
+            this.contents = requireNonNull(contents);
         }
 
         @Override
@@ -611,7 +613,13 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
 
         public UnboundRuntimeVisibleParameterAnnotationsAttribute(List<List<Annotation>> elements) {
             super(Attributes.runtimeVisibleParameterAnnotations());
-            this.elements = List.copyOf(elements);
+            // deep copy
+            var array = elements.toArray().clone();
+            for (int i = 0; i < array.length; i++) {
+                array[i] = List.copyOf((List<?>) array[i]);
+            }
+
+            this.elements = SharedSecrets.getJavaUtilCollectionAccess().listFromTrustedArray(array);
         }
 
         @Override
@@ -684,7 +692,13 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
                                         Optional<ClassEntry> outerClass,
                                         Optional<Utf8Entry> innerName,
                                         int flagsMask)
-            implements InnerClassInfo {}
+            implements InnerClassInfo {
+        public UnboundInnerClassInfo {
+            requireNonNull(innerClass);
+            requireNonNull(outerClass);
+            requireNonNull(innerName);
+        }
+    }
 
     public record UnboundLineNumberInfo(int startPc, int lineNumber)
             implements LineNumberInfo { }
@@ -693,64 +707,84 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
                                            Utf8Entry name,
                                            Utf8Entry type,
                                            int slot)
-            implements LocalVariableInfo { }
+            implements LocalVariableInfo {
+        public UnboundLocalVariableInfo {
+            requireNonNull(name);
+            requireNonNull(type);
+        }
+    }
 
     public record UnboundLocalVariableTypeInfo(int startPc, int length,
                                                Utf8Entry name,
                                                Utf8Entry signature,
                                                int slot)
-            implements LocalVariableTypeInfo { }
+            implements LocalVariableTypeInfo {
+        public UnboundLocalVariableTypeInfo {
+            requireNonNull(name);
+            requireNonNull(signature);
+        }
+    }
 
     public record UnboundMethodParameterInfo(Optional<Utf8Entry> name, int flagsMask)
-            implements MethodParameterInfo {}
+            implements MethodParameterInfo {
+        public UnboundMethodParameterInfo {
+            requireNonNull(name);
+        }
+    }
 
     public record UnboundModuleExportInfo(PackageEntry exportedPackage,
                                           int exportsFlagsMask,
                                           List<ModuleEntry> exportsTo)
             implements ModuleExportInfo {
-        public UnboundModuleExportInfo(PackageEntry exportedPackage, int exportsFlagsMask,
+        public UnboundModuleExportInfo {
-                                       List<ModuleEntry> exportsTo) {
+            requireNonNull(exportedPackage);
-            this.exportedPackage = exportedPackage;
+            exportsTo = List.copyOf(exportsTo);
-            this.exportsFlagsMask = exportsFlagsMask;
-            this.exportsTo = List.copyOf(exportsTo);
         }
     }
 
     public record UnboundModuleHashInfo(ModuleEntry moduleName,
-                                        byte[] hash) implements ModuleHashInfo { }
+                                        byte[] hash) implements ModuleHashInfo {
+        public UnboundModuleHashInfo {
+            requireNonNull(moduleName);
+            requireNonNull(hash);
+        }
+    }
 
     public record UnboundModuleOpenInfo(PackageEntry openedPackage, int opensFlagsMask,
                                         List<ModuleEntry> opensTo)
             implements ModuleOpenInfo {
-        public UnboundModuleOpenInfo(PackageEntry openedPackage, int opensFlagsMask,
+        public UnboundModuleOpenInfo {
-                                     List<ModuleEntry> opensTo) {
+            requireNonNull(openedPackage);
-            this.openedPackage = openedPackage;
+            opensTo = List.copyOf(opensTo);
-            this.opensFlagsMask = opensFlagsMask;
-            this.opensTo = List.copyOf(opensTo);
         }
     }
 
     public record UnboundModuleProvideInfo(ClassEntry provides,
                                            List<ClassEntry> providesWith)
             implements ModuleProvideInfo {
-        public UnboundModuleProvideInfo(ClassEntry provides, List<ClassEntry> providesWith) {
+        public UnboundModuleProvideInfo {
-            this.provides = provides;
+            requireNonNull(provides);
-            this.providesWith = List.copyOf(providesWith);
+            providesWith = List.copyOf(providesWith);
         }
     }
 
     public record UnboundModuleRequiresInfo(ModuleEntry requires, int requiresFlagsMask,
                                             Optional<Utf8Entry> requiresVersion)
-            implements ModuleRequireInfo {}
+            implements ModuleRequireInfo {
+        public UnboundModuleRequiresInfo {
+            requireNonNull(requires);
+            requireNonNull(requiresVersion);
+        }
+    }
 
     public record UnboundRecordComponentInfo(Utf8Entry name,
                                              Utf8Entry descriptor,
                                              List<Attribute<?>> attributes)
             implements RecordComponentInfo {
-        public UnboundRecordComponentInfo(Utf8Entry name, Utf8Entry descriptor, List<Attribute<?>> attributes) {
+        public UnboundRecordComponentInfo {
-            this.name = name;
+            requireNonNull(name);
-            this.descriptor = descriptor;
+            requireNonNull(descriptor);
-            this.attributes = List.copyOf(attributes);
+            attributes = List.copyOf(attributes);
         }
     }
 
@@ -759,7 +793,9 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
                                         Annotation annotation) implements TypeAnnotation {
 
         public UnboundTypeAnnotation {
+            requireNonNull(targetInfo);
             targetPath = List.copyOf(targetPath);
+            requireNonNull(annotation);
         }
     }
 
@@ -786,7 +822,7 @@ public abstract sealed class UnboundAttribute<T extends Attribute<T>>
                                       Collection<ModuleProvideInfo> provides)
         {
             super(Attributes.module());
-            this.moduleName = moduleName;
+            this.moduleName = requireNonNull(moduleName);
             this.moduleFlags = moduleFlags;
             this.moduleVersion = moduleVersion;
             this.requires = List.copyOf(requires);