FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
There seems to be a concurrency problem inside java.util.ResourceBundle.getBundle() caching logic where it's possible that the algorithm returns NONEXISTENT_BUNDLE, which is not supposed to be returned.

ResrouceBundle.putBundleInCache() could return NONEXISTENT_BUNDLE if another thread has put it in the cache. It should check the result of cacheList.putIfAbsent() to not be NONEXISTENT_BUNDLE


ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.util.MissingResourceException: Can't find resource for bundle java.util.ResourceBundle$1, key NumberElements
at java.util.ResourceBundle.getObject(ResourceBundle.java:395) ~[na:1.7.0_67]
at java.util.ResourceBundle.getObject(ResourceBundle.java:392) ~[na:1.7.0_67]
at java.util.ResourceBundle.getStringArray(ResourceBundle.java:372) ~[na:1.7.0_67]
at java.text.DecimalFormatSymbols.initialize(DecimalFormatSymbols.java:541) ~[na:1.7.0_67]
at java.text.DecimalFormatSymbols.<init>(DecimalFormatSymbols.java:94) ~[na:1.7.0_67]
at java.text.DecimalFormatSymbols.getInstance(DecimalFormatSymbols.java:157) ~[na:1.7.0_67]
at java.util.Formatter.getZero(Formatter.java:2251) ~[na:1.7.0_67]
at java.util.Formatter.<init>(Formatter.java:1877) ~[na:1.7.0_67]
at java.util.Formatter.<init>(Formatter.java:1898) ~[na:1.7.0_67]
at java.lang.String.format(String.java:2790) ~[na:1.7.0_67]

REPRODUCIBILITY :
This bug can be reproduced rarely.

---------- BEGIN SOURCE ----------
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Arrays;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.Random;
import java.util.ResourceBundle;
import java.util.concurrent.atomic.AtomicInteger;

public class ResourceBundleTest {

  static Random rnd = new Random();
  static AtomicInteger ctr = new AtomicInteger();
  static AtomicInteger tryCounter = new AtomicInteger();

  public static void main(String[] args) throws Exception {
    final CL1 cl = new CL1(new URL[0]);
    for (int i = 0; i < 10; i++) {
      new Thread(new Runnable() {

        @Override
        public void run() {
          while (true) {
            if (rnd.nextFloat() > 0.8) {
              ctr.incrementAndGet();
            }
            int c = tryCounter.incrementAndGet();
            if (c % 1000 == 0) {
              System.out.println(c);
            }
            try {
              ResourceBundle bundle = ResourceBundle.getBundle("" + ctr.get(), Locale.getDefault(), cl);
              if (bundle.getClass().getName().contains("$1")) {
                System.err.println("ERROR: " + bundle + " " + c);
                System.exit(1);
              }
            }
            catch (MissingResourceException e) {
            }
          }
        }

      }).start();
    }
  }

  static class CL1 extends URLClassLoader {

    private Random r = new Random();

    public CL1(URL[] urls) {
      super(urls);
    }

    @Override
    public Class<?> loadClass(String name) throws ClassNotFoundException {
      if (r.nextBoolean()) {
        return Bundle.class;
      }
      else {
        throw new ClassNotFoundException();
      }
    }

  }

  public static class Bundle extends ResourceBundle {

    @Override
    protected Object handleGetObject(String key) {
      return new Object();
    }

    @Override
    public Enumeration<String> getKeys() {
      return Collections.enumeration(Arrays.asList("foo"));
    }

  }

}

---------- END SOURCE ----------