The proxy class EnhancerByCGLIB constructors have wrong Exception table

[hengyunabc]

demo

public class Hello {
    public Hello() {
        try {
            this.getClass().getMethods()[0].invoke(null);
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }
}

javap -v Hello.class result:

  public Hello();
    descriptor: ()V
    flags: ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=1
         0: aload_0
         1: invokespecial #8                  // Method java/lang/Object."<init>":()V
         4: aload_0
         5: invokevirtual #10                 // Method java/lang/Object.getClass:()Ljava/lang/Class;
         8: invokevirtual #14                 // Method java/lang/Class.getMethods:()[Ljava/lang/reflect/Method;
        11: iconst_0
        12: aaload
        13: aconst_null
        14: iconst_0
        15: anewarray     #3                  // class java/lang/Object
        18: invokevirtual #20                 // Method java/lang/reflect/Method.invoke:(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object;
        21: pop
        22: goto          30
        25: astore_1
        26: aload_1
        27: invokevirtual #26                 // Method java/lang/Throwable.printStackTrace:()V
        30: return
      Exception table:
         from    to  target type
             4    22    25   Class java/lang/Throwable

Exception table star from 4.

cglib demo

public class CglibDemo implements MethodInterceptor {

    public static <T> T newInstance(Class<T> clazz) {
        try {
            CglibDemo interceptor = new CglibDemo();
            Enhancer e = new Enhancer();

            UndeclaredThrowableStrategy ss = new UndeclaredThrowableStrategy(
                    java.lang.reflect.UndeclaredThrowableException.class);
            e.setStrategy(ss);
            e.setSuperclass(clazz);
            e.setCallback(interceptor);
            return (T) e.create();
        } catch (Throwable e) {
            e.printStackTrace();
            throw new Error(e.getMessage());
        }
    }

    @Override
    public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
        System.err.println("xxx");
        return null;
    }

    public static class Person {

        public Person() {
            System.err.println("xxx");
        }

        public String getName() {
            return "Hans Hansen";
        }

        public boolean isEmployee() {
            return true;
        }
    }

    public static void main(String[] args) throws IOException {
        Person callsToPersonRegistrant = newInstance(Person.class);
        System.in.read();
    }

}

Use arthas dump command to dump cglib class:

• https://arthas.aliyun.com/doc/en/dump

./as.sh --select CglibDemo

[arthas@83698]$ dump CglibDemo$Person$$EnhancerByCGLIB*
 HASHCODE  CLASSLOADER                                    LOCATION
 2a139a55  +-sun.misc.Launcher$AppClassLoader@2a139a55    /Users/hengyunabc/logs/arthas/classdump/sun.misc.Launcher$AppClassLoader-2a139a55/CglibDemo$Person$$EnhancerByCGLIB$$
             +-sun.misc.Launcher$ExtClassLoader@6c819144  49b2ccd2.class

The cglib proxy class star from 0:

  public CglibDemo$Person$$EnhancerByCGLIB$$49b2ccd2();
    descriptor: ()V
    flags: ACC_PUBLIC
    Code:
      stack=3, locals=1, args_size=1
         0: aload_0
         1: dup
         2: invokespecial #200                // Method CglibDemo$Person."<init>":()V
         5: invokestatic  #44                 // Method CGLIB$BIND_CALLBACKS:(Ljava/lang/Object;)V
         8: return
         9: athrow
        10: new           #66                 // class java/lang/reflect/UndeclaredThrowableException
        13: dup_x1
        14: swap
        15: invokespecial #69                 // Method java/lang/reflect/UndeclaredThrowableException."<init>":(Ljava/lang/Throwable;)V
        18: athrow
      Exception table:
         from    to  target type
             0     9     9   Class java/lang/RuntimeException
             0     9     9   Class java/lang/Error
             0     9    10   Class java/lang/Throwable

The CglibDemo works in cglib 3.2.12, error in cglib 3.3.0:

java.lang.IllegalStateException: Unable to load cache item
	at net.sf.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:79)
	at net.sf.cglib.core.internal.LoadingCache.get(LoadingCache.java:34)
	at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:119)
	at net.sf.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:294)
	at net.sf.cglib.proxy.Enhancer.createHelper(Enhancer.java:480)
	at net.sf.cglib.proxy.Enhancer.create(Enhancer.java:305)
	at CglibDemo2.newInstance(CglibDemo2.java:22)
	at CglibDemo2.main(CglibDemo2.java:51)
Caused by: java.lang.VerifyError: Stack map does not match the one at exception handler 9
Exception Details:
  Location:
    CglibDemo2$Person$$EnhancerByCGLIB$$21a4f41d.<init>()V @9: athrow
  Reason:
    Current frame's flags are not assignable to stack map frame's.
  Current Frame:
    bci: @0
    flags: { flagThisUninit }
    locals: { uninitializedThis }
    stack: { 'java/lang/RuntimeException' }
  Stackmap Frame:
    bci: @9
    flags: { }
    locals: { }
    stack: { 'java/lang/Throwable' }
  Bytecode:
    0x0000000: 2a59 b700 c6b8 002c b1bf bb00 425a 5fb7
    0x0000010: 0045 bf                                
  Exception Handler Table:
    bci [0, 9] => handler: 9
    bci [0, 9] => handler: 9
    bci [0, 9] => handler: 10
  Stackmap Table:
    full_frame(@9,{},{Object[#64]})
    same_locals_1_stack_item_frame(@10,Object[#64])

	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:348)
	at net.sf.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:467)
	at net.sf.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:339)
	at net.sf.cglib.proxy.Enhancer.generate(Enhancer.java:492)
	at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:96)
	at net.sf.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:94)
	at net.sf.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at net.sf.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61)
	... 7 more
Exception in thread "main" java.lang.Error: Unable to load cache item
	at CglibDemo2.newInstance(CglibDemo2.java:25)
	at CglibDemo2.main(CglibDemo2.java:51)

• Reference: spring-projects/spring-framework@9bd3a53