RFR: 8310628: GcInfoBuilder.c missing JNI Exception checks

[Mandy Chung]

On Thu, 22 Jun 2023 10:10:07 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

> JNI calls were identified, where we do not check for a pending Exception afterwards.
> 
> (JDK-8162530 cleaned up up some of these kind of issues some years back, but more were found.)
> 
> I tested a code change to manually create an Exception before some of the new ExceptionCheck calls, and this is correctly recognised, we see an Exception thrown by the native getLastGcInfo0, e.g. 
> 
> java.lang.NullPointerException: XXX Test Exception
>         at jdk.management/com.sun.management.internal.GcInfoBuilder.getLastGcInfo0(Native Method)
>         at jdk.management/com.sun.management.internal.GcInfoBuilder.getLastGcInfo(GcInfoBuilder.java:77)
>         at jdk.management/com.sun.management.internal.GarbageCollectorExtImpl.getLastGcInfo(GarbageCollectorExtImpl.java:69)
>         at LastGCInfo.main(LastGCInfo.java:53)
>         at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
>         at java.base/java.lang.reflect.Method.invoke(Method.java:580)
>         at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
>         at java.base/java.lang.Thread.run(Thread.java:1570)
> 
> Tested with all of test/jdk/com/sun/management including test/jdk/com/sun/management/GarbageCollectorMXBean/LastGCInfo.java

Looks fine.   It may worth refactoring the code to set an element in an utility method.

    jobject obj = JNU_NewObjectByName(env, class_name, signature, value);
    if ((*env)->ExceptionCheck(env)) {
        return;
    }
    (*env)->SetObjectArrayElement(env, array, index, obj);

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PR Review: https://git.openjdk.org/jdk/pull/14613#pullrequestreview-1493765649