Name: vrR10176 Date: 02/27/2002



JNI function DefineClass() does not detect circularity if loaded class
is its own superclass. In this case superclass can not be loaded and
DefineClass() throws NoClassDefFoundError instead of
ClassCircularityError.

Java Native Interface Specification, section 4 - "JNI Functions"
says about the function:

"jclass DefineClass(JNIEnv *env, jobject loader, const jbyte *buf, jsize bufLen);

Loads a class from a buffer of raw class data.
 ...
THROWS:
...
ClassCircularityError: if a class or interface would be its own
superclass or superinterface.
...
"

This bug causes failure of new JCK-1.4a test:
vm/jni/DefineClass/dfcl001/dfcl00103m1/dfcl00103m1.html

To reproduce the issue execute the following test.
Test tries to create class instance from a buffer of raw class data
representing a class 'test' which is its own superclass.

------------ dfcltest.java -------------------------------

public class dfcltest {

    public native Class nativeDefineCls();

    static {
        System.loadLibrary("dfcltest");
    }

    public static void main(String argv[]) {
        dfcltest tob = new dfcltest();
        try {
            Class cl = tob.nativeDefineCls();
            System.out.println("ClassCircularityError expected");
        } catch (ClassCircularityError e) {
            System.out.println("Test passed " + e);
        } catch (Throwable e) {
            System.out.println("Exception caught: " + e);
        }
    }
}

------------ dfcltest.c ----------------------------------

#include "jni.h"

JNIEXPORT jclass JNICALL Java_dfcltest_nativeDefineCls (JNIEnv *env, jobject obj)
{

/* byte array contains the raw class file data of the class:
class test extends test{
}
*/

    unsigned char buf[34]= {
        0xca, 0xfe, 0xba, 0xbe, 0x00, 0x03, 0x00, 0x2d,
        0x00, 0x03, 0x07, 0x00, 0x02, 0x01, 0x00, 0x04,
        0x74, 0x65, 0x73, 0x74, 0x00, 0x01, 0x00, 0x01,
        0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x00, 0x00
    };
    return (*env) -> DefineClass(env, "test", 0, (const jbyte*)buf, 34);

}

------------ Logs ----------------------------------------
% ls -1
dfcltest.c
dfcltest.java
jni.h
jni_md.h

%javac -d . dfcltest.java
%
%cc -G -KPIC -o libdfcltest.so dfcltest.c
%
%java -version
java version "1.4.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-b92)
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)
%
% java -Xfuture dfcltest
Exception caught: java.lang.NoClassDefFoundError: test
%

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