StackWalker::getCallerClass throws UnsupportedOperationException

[Michael Rasmussen]

Hi

StackWalker::getCallerClass can throw "UnsupportedOperationException: StackWalker::getCallerClass called from @CallerSensitive", depending on how the underlying fetchNextBatch/fill_in_frames splits the stacktrace.

This seems to be a result of what was introduced in JDK-8157464.

The following code example produces the exception (Tested on the jdk.java.net releases of OpenJDK 10 and 11-ea build 28):

// ----- snip ----
package com.test;

import java.lang.reflect.Method;

public class Main {
  public static void main(String[] args) throws Exception {
    Method method = Main.class.getDeclaredMethod("bar");
    Method m = Method.class.getMethod("invoke", Object.class, Object[].class);

    // get 'm' past compilation threshold
    for (int i = 0; i < 15; i++) {
      m.invoke(Main.class.getDeclaredMethod("dummy"), null, null);
    }

    m.invoke(m, m, new Object[] {method, new Object[] {null, null}});
  }

  static void dummy() { }

  static void bar() {
    System.out.println(StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE).getCallerClass());
  }
}
// ----- snip ----

The above code is constructed so Method::invoke ends up as the frame for which index==start_index in fill_in_frames, thus causing the exception.

For example output, including stackwalk debug output, see below.

// ----- snip ----
$ java -Xlog:stackwalk=debug com.test.Main
[0.154s][debug][stackwalk] Start walking: mode 6 skip 0 frames batch size 6
[0.155s][debug][stackwalk]   skip  java.lang.StackStreamFactory$AbstractStackWalker::callStackWalk
[0.156s][debug][stackwalk]   skip  java.lang.StackStreamFactory$AbstractStackWalker::beginStackWalk
[0.157s][debug][stackwalk]   skip  java.lang.StackStreamFactory$AbstractStackWalker::walk
[0.158s][debug][stackwalk]   skip  java.lang.StackStreamFactory$CallerClassFinder::findCaller
[0.159s][debug][stackwalk]   skip  java.lang.StackWalker::getCallerClass
[0.160s][debug][stackwalk] fill_in_frames limit=6 start=2 frames length=8
[0.161s][debug][stackwalk]   2: frame method:  com.test.Main::bar bci=9
[0.162s][debug][stackwalk]   3: frame method:  jdk.internal.reflect.NativeMethodAccessorImpl::invoke0 bci=0
[0.162s][debug][stackwalk]   4: frame method:  jdk.internal.reflect.NativeMethodAccessorImpl::invoke bci=100
[0.163s][debug][stackwalk]   5: frame method:  jdk.internal.reflect.DelegatingMethodAccessorImpl::invoke bci=6
[0.163s][debug][stackwalk]   6: frame method:  java.lang.reflect.Method::invoke bci=59
[0.168s][debug][stackwalk]   7: frame method:  jdk.internal.reflect.GeneratedMethodAccessor1::invoke bci=48
[0.169s][debug][stackwalk] StackWalk::fetchNextBatch frame_count 8 existing_stream 0x000000a5b8ffb5f0 start 2 frames 10
[0.170s][debug][stackwalk] fill_in_frames limit=8 start=2 frames length=10
[0.171s][debug][stackwalk]   2: frame method:  jdk.internal.reflect.DelegatingMethodAccessorImpl::invoke bci=6
[0.171s][debug][stackwalk]   3: frame method:  java.lang.reflect.Method::invoke bci=59
[0.172s][debug][stackwalk]   4: frame method:  jdk.internal.reflect.GeneratedMethodAccessor1::invoke bci=48
[0.173s][debug][stackwalk]   5: frame method:  jdk.internal.reflect.DelegatingMethodAccessorImpl::invoke bci=6
[0.174s][debug][stackwalk]   6: frame method:  java.lang.reflect.Method::invoke bci=59
[0.175s][debug][stackwalk]   7: frame method:  jdk.internal.reflect.NativeMethodAccessorImpl::invoke0 bci=0
[0.175s][debug][stackwalk]   8: frame method:  jdk.internal.reflect.NativeMethodAccessorImpl::invoke bci=100
[0.179s][debug][stackwalk]   9: frame method:  jdk.internal.reflect.DelegatingMethodAccessorImpl::invoke bci=6
[0.180s][debug][stackwalk] StackWalk::fetchNextBatch frame_count 8 existing_stream 0x000000a5b8ffb5f0 start 2 frames 10
[0.181s][debug][stackwalk] fill_in_frames limit=8 start=2 frames length=10
[0.181s][debug][stackwalk]   2: frame method:  java.lang.reflect.Method::invoke bci=59
Exception in thread "main" java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at com.test.Main.main(Main.java:15)
Caused by: java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        ... 5 more
Caused by: java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        ... 8 more
Caused by: java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        ... 11 more
Caused by: java.lang.UnsupportedOperationException: StackWalker::getCallerClass called from @CallerSensitive java.lang.reflect.Method.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; method
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.fetchStackFrames(Native Method)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.fetchStackFrames(StackStreamFactory.java:386)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.getNextBatch(StackStreamFactory.java:322)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.peekFrame(StackStreamFactory.java:263)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.hasNext(StackStreamFactory.java:351)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.nextFrame(StackStreamFactory.java:336)
        at java.base/java.lang.StackStreamFactory$CallerClassFinder.consumeFrames(StackStreamFactory.java:683)
        at java.base/java.lang.StackStreamFactory$CallerClassFinder.consumeFrames(StackStreamFactory.java:612)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.doStackWalk(StackStreamFactory.java:306)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.callStackWalk(Native Method)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.beginStackWalk(StackStreamFactory.java:370)
        at java.base/java.lang.StackStreamFactory$AbstractStackWalker.walk(StackStreamFactory.java:243)
        at java.base/java.lang.StackStreamFactory$CallerClassFinder.findCaller(StackStreamFactory.java:670)
        at java.base/java.lang.StackWalker.getCallerClass(StackWalker.java:600)
        at com.test.Main.bar(Main.java:21)
        ... 15 more
// ----- snip ----

Kind regards
/Michael