JDK 8 incorectly processes nameless parameters in MethodParameters Attribute

[dalibor topic]

Hi Mihail,

could you file an issue at bugs.java.com and let us know which incident 
id you receive, please?

cheers,
dalibor topic

On 14.11.2016 10:58, Михаил Богданов wrote:
> JDK 8 incorrectly processes nameless (name=null) parameters in MethodParameters attribute. Actually problem in inconsistency between Hotspot and reflection:
> Hotspot  VM constructs nameless parameter with empty string name that cause Executable.verifyParameters to throw MalformedParametersException.
> //Code to reproduce:import jdk.internal.org.objectweb.asm.ClassWriter;
> import jdk.internal.org.objectweb.asm.MethodVisitor;
> import jdk.internal.org.objectweb.asm.Opcodes;
>
> import java.lang.reflect.Method;
> import java.net.URL;
> import java.net.URLClassLoader;
>
> public class Bug {
>
>     public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException {
>         ClassWriter writer = new ClassWriter(Opcodes.ASM5);
>         writer.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC | Opcodes.ACC_INTERFACE | Opcodes.ACC_ABSTRACT, "Test", null, "java/lang/Object", null);
>         MethodVisitor test = writer.visitMethod(Opcodes.ACC_PUBLIC | Opcodes.ACC_ABSTRACT, "test", "(I)V", null, null);
>         test.visitParameter(null, 0);
>         test.visitEnd();
>
>         writer.visitEnd();
>         final byte[] bytes = writer.toByteArray();
>
>         URLClassLoader urlClassLoader = new URLClassLoader(new URL[0], ClassLoader.getSystemClassLoader()) {
>             @Override
>             protected Class<?> findClass(String name) throws ClassNotFoundException {
>                 if (name.equals("Test")) {
>                     return defineClass("Test", bytes, 0, bytes.length);
>                 }
>                 return super.findClass(name);
>             }
>         };
>
>
>         Class<?> clazz = urlClassLoader.loadClass("Test");
>         Method method = clazz.getDeclaredMethod("test", Integer.TYPE);
> //        Exception in thread "main" java.lang.reflect.MalformedParametersException: Invalid parameter name ""
> //        at java.lang.reflect.Executable.verifyParameters(Executable.java:386)
> //        at java.lang.reflect.Executable.privateGetParameters(Executable.java:416)
> //        at java.lang.reflect.Executable.getParameters(Executable.java:357)
> //        at Bug.main(Bug.java:37)
>         method.getParameters();
>     }
> }
> Best regards,   Max
>

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