Repeatedly thrown ArrayIndexOutOfBoundsException stop producing stack traces

Question

I'm writing tests for my program. Sometimes my tests work, and sometimes they fail. I'm trying to track down all of the sources of nondeterminism.

Here's a simple, self-contained example of my problem:

import java.util.ArrayList;

public class ArrayExceptions {
    public static void main(String[] args) {
        final int ITERATIONS = 10000;
        ArrayList<Integer> list = new ArrayList<>();
        try {
            list.get(-1);
        } catch(ArrayIndexOutOfBoundsException e) {
            e.printStackTrace();
        }
        for(int i = 0; i < ITERATIONS; i++) {
            try{
                list.get(-1);
            } catch (ArrayIndexOutOfBoundsException e) {
                if(e.getMessage() == null) {
                    System.out.println(i);
                    break;
                }
            }
        }
        for(int i = 0; i < 10; i++) {
            try {
                list.get(-1);
            } catch(ArrayIndexOutOfBoundsException e) {
                e.printStackTrace();
            }
        }
    }
}

This program creates an ArrayList. It tries to access element -1 repeatedly. Initially, this creates a detailed backtrace and a message alongside the ArrayIndexOutOfBoundsException. However, if you call it enough times (where 'enough' seems to be about 5500) the thrown exception lacks a backtrace and a message.

The output of this program varies from run to run. Here it exits early, at 5494 iterations:

java.lang.ArrayIndexOutOfBoundsException: -1
    at java.util.ArrayList.elementData(ArrayList.java:418)
    at java.util.ArrayList.get(ArrayList.java:431)
    at ArrayExceptions.main(ArrayExceptions.java:8)
5494
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException

Here it fails late, at 5540 iterations:

java.lang.ArrayIndexOutOfBoundsException: -1
    at java.util.ArrayList.elementData(ArrayList.java:418)
    at java.util.ArrayList.get(ArrayList.java:431)
    at ArrayExceptions.main(ArrayExceptions.java:8)
5540
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException

Why's it doing this?

score 6 · Accepted Answer · answered Oct 18 '17 at 23:20

6

Nevermind, figured it out.

Pass -XX:-OmitStackTraceInFastThrow as a command line option to the JVM to turn this behavior off. See also NullPointerException stack trace not available without debug agent

answered Oct 18 '17 at 23:20

Nick ODell

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Repeatedly thrown ArrayIndexOutOfBoundsException stop producing stack traces

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