java - Gson 类中的VerifyError

Question

我使用以下代码对一个类进行 rebase :

DynamicType.Unloaded unloaded = new ByteBuddy().with(TypeValidation.DISABLED).rebase(typeDescription,
                ClassFileLocator.Simple.of(className, classBytes,
                        ClassFileLocator.ForClassLoader.of((ClassLoader) classLoader))).method(
                ElementMatchers.isPackagePrivate().and(ElementMatchers.not(ElementMatchers.isAbstract()))).intercept(
                MethodDelegation.to(PackagePrivateInterceptor.class)).transform(
                MethodTransformer.Simple.withModifiers(Visibility.PUBLIC)).make();
        return new ClassPair(unloaded.load((ClassLoader) classLoader,
                ClassLoadingStrategy.Default.INJECTION.withProtectionDomain(
                        classLoader.getClass().getProtectionDomain())).getLoaded(), unloaded.getBytes());

加载类时class com.google.gson.internal.ConstructorConstructor

它会遍历构造函数，直到最后到达 com.google.gson.internal.LinkedTreeMap 的类初始值设定项。

在初始化期间，我收到一个VerifyError:

1:24:20.227 [main] ERROR   [io.hakansson.dynamicjar.core.main.Bootstrap] - java.lang.RuntimeException: java.lang.VerifyError: Illegal type at constant pool entry 195 in class com.google.gson.internal.LinkedTreeMap$1Exception Details:  Location:    com/google/gson/internal/LinkedTreeMap$1.thenComparing$accessor$vT023QbO(Ljava/util/function/Function;)Ljava/util/Comparator; @2: invokespecial  Reason:    Constant pool index 195 is invalid  Bytecode:    0x0000000: 2a2b b700 c3b0                             at io.hakansson.dynamicjar.core.api.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:52)    at io.hakansson.dynamicjar.core.main.Bootstrap.main(Bootstrap.java:42)Caused by: java.lang.VerifyError: Illegal type at constant pool entry 195 in class com.google.gson.internal.LinkedTreeMap$1Exception Details:  Location:    com/google/gson/internal/LinkedTreeMap$1.thenComparing$accessor$vT023QbO(Ljava/util/function/Function;)Ljava/util/Comparator; @2: invokespecial  Reason:    Constant pool index 195 is invalid  Bytecode:    0x0000000: 2a2b b700 c3b0                             at com.google.gson.internal.LinkedTreeMap.classInitializer$oNOjADym(LinkedTreeMap.java:40)    at com.google.gson.internal.LinkedTreeMap.(LinkedTreeMap.java)    at com.google.gson.internal.ConstructorConstructor$13.construct$original$gt92dwVY(ConstructorConstructor.java:207)    at com.google.gson.internal.ConstructorConstructor$13.construct$original$gt92dwVY$accessor$lof1omy8(ConstructorConstructor.java)    at com.google.gson.internal.ConstructorConstructor$13$auxiliary$oB71rVyd.call(Unknown Source)    at io.hakansson.dynamicjar.nestedjarclassloader.PackagePrivateInterceptor.intercept(PackagePrivateInterceptor.java:29)    at com.google.gson.internal.ConstructorConstructor$13.construct(ConstructorConstructor.java)    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:167)    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:145)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read$original$ZTjOtCtb(ReflectiveTypeAdapterFactory.java:116)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read$original$ZTjOtCtb$accessor$WgRdwpwl(ReflectiveTypeAdapterFactory.java)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1$auxiliary$41HBhnNS.call(Unknown Source)    at io.hakansson.dynamicjar.nestedjarclassloader.PackagePrivateInterceptor.intercept(PackagePrivateInterceptor.java:29)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:216)    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read$original$bOjIYDn5(TypeAdapterRuntimeTypeWrapper.java:40)    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read$original$bOjIYDn5$accessor$hMWEZRZS(TypeAdapterRuntimeTypeWrapper.java)    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper$auxiliary$U1tyihKy.call(Unknown Source)    at io.hakansson.dynamicjar.nestedjarclassloader.PackagePrivateInterceptor.intercept(PackagePrivateInterceptor.java:29)    at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java)    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:82)    at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read$original$ZTjOtCtb(ReflectiveTypeAdapterFactory.java:116)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read$original$ZTjOtCtb$accessor$WgRdwpwl(ReflectiveTypeAdapterFactory.java)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1$auxiliary$41HBhnNS.call(Unknown Source)    at io.hakansson.dynamicjar.nestedjarclassloader.PackagePrivateInterceptor.intercept(PackagePrivateInterceptor.java:29)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java)    at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:216)    at com.google.gson.Gson.fromJson(Gson.java:879)    at com.google.gson.Gson.fromJson(Gson.java:817)

For reference, the interceptor basically just manually checks for package-private access (since package private methods were made public) and then just calls superCall.call(). I don't believe the issue lies there.

Any ideas?

EDIT:Here's the PackagePrivateInterceptor: public class PackagePrivateInterceptor {

@RuntimeType
@BindingPriority(1)
public static Object intercept(@SuperCall Callable<?> superCall, @Origin Class targetClass, @Origin String method) throws
        Exception
{

    Class callingClass = new InternalSecurityManager().getCallingClass();
    String targetPackage = targetClass.getPackage().getName();
    if (!callingClass.getPackage().getName().equals(targetPackage)) {
        throw new IllegalAccessError(callingClass + " cannot access method " + method + " of Class " + targetClass);
    }

    //Default:
    return superCall.call();
}

private static class InternalSecurityManager extends SecurityManager {
    Class getCallingClass() {
        Class[] classContext = getClassContext();
        for (Class current : classContext) {
            if (current.getName().startsWith("java.") ||
                    current.getName().equals(PackagePrivateInterceptor.class.getName()) ||
                    current.getName().equals(InternalSecurityManager.class.getName()))
            {
                continue;
            }
            return current;
        }
        throw new IllegalStateException("Failed to find calling Class");
    }
}

编辑2:以下代码不会触发该问题:

//Only package-private methods should be proxied.
            DynamicType.Unloaded unloaded = new ByteBuddy().with(TypeValidation.DISABLED).rebase(typeDescription,
                    ClassFileLocator.Simple.of(className, classBytes,
                            ClassFileLocator.ForClassLoader.of((ClassLoader) classLoader))).method(
                    ElementMatchers.isPackagePrivate().and(ElementMatchers.not(ElementMatchers.isAbstract()))).intercept(
                    MethodDelegation.to(PackagePrivateInterceptor.class)).transform(
                    MethodTransformer.Simple.withModifiers(Visibility.PUBLIC)).make();
            DynamicType.Loaded loaded = unloaded.load((ClassLoader) classLoader,
                    ClassLoadingStrategy.Default.INJECTION.withProtectionDomain(
                            classLoader.getClass().getProtectionDomain()));
            if (className.equals("com.google.gson.internal.LinkedTreeMap"))
                System.out.println(DatatypeConverter.printHexBinary(loaded.getBytes()));
            return new ClassPair(loaded.getLoaded(), unloaded.getBytes());

但以下情况确实如此:

//All non-private methods should be proxied
            //TODO: Actually, the class itself should be made visible and still only package-private methods should be proxied.
            DynamicType.Unloaded unloaded = new ByteBuddy().with(TypeValidation.DISABLED).rebase(typeDescription,
                    ClassFileLocator.Simple.of(className, classBytes,
                            ClassFileLocator.ForClassLoader.of((ClassLoader) classLoader))).method(
                    ElementMatchers.not(ElementMatchers.isPrivate()).and(
                            ElementMatchers.not(ElementMatchers.isAbstract()))).intercept(
                    MethodDelegation.to(PackagePrivateInterceptor.class)).transform(
                    MethodTransformer.Simple.withModifiers(Visibility.PUBLIC)).make();
            return new ClassPair(unloaded.load((ClassLoader) classLoader,
                    ClassLoadingStrategy.Default.INJECTION.withProtectionDomain(
                            classLoader.getClass().getProtectionDomain())).getLoaded(), unloaded.getBytes());

Answer 1

这确实是Byte Buddy的一个bug。问题在于您正在 Java 8 VM 上重新构建 Java 6 类，其中 Comparable 接口(interface)正在实现多个默认方法。您指示 Byte Buddy 覆盖这些方法，还指示库从覆盖的实现中调用这些默认方法。即使 VM 运行 Java 8，这对于 Java 6 类文件也是不合法的。

如果我将您的匹配器更改为:

not(isPrivate().or(isAbstract()).or(isDefaultMethod()))

错误消失。我将在 Byte Buddy 的 future 版本中修复此问题。

此错误当前未被 Byte Buddy 或 ASM 捕获，从而产生奇怪的错误消息。

更新:该错误现已在版本 1.4.13 中得到解决。