8030192: TESTFAIL: java/util/logging/TestLoggerBundleSync.java failed with NPE

This is a test bug - loggers held in local variables can be arbitrarily gc'ed if that variable is no longer used. The fix makes sure that the loggers won't be arbitrarily gc'ed before the test is complete.

Reviewed-by: mchung

jdk/test/java/util/logging/TestLoggerBundleSync.java

@@ -190,8 +190,10 @@ public class TestLoggerBundleSync {
         final static class MyHandler extends Handler {
             volatile ResourceBundle rb;
             volatile String rbName;
+            volatile int count = 0;
             @Override
             public synchronized void publish(LogRecord record) {
+                count++;
                 rb = record.getResourceBundle();
                 rbName = record.getResourceBundleName();
             }
@@ -227,23 +229,51 @@ public class TestLoggerBundleSync {
                         Logger ll = Logger.getLogger(l.getName()+".bie.bye");
                         ResourceBundle hrb;
                         String hrbName;
+                        if (handler.getLevel() != Level.FINEST) {
+                            throw new RuntimeException("Handler level is not finest: "
+                                    + handler.getLevel());
+                        }
+                        final int countBefore = handler.count;
                         ll.setLevel(Level.FINEST);
                         ll.addHandler(handler);
                         ll.fine("dummy");
                         ll.removeHandler(handler);
+                        final int countAfter = handler.count;
+                        if (countBefore == countAfter) {
+                            throw new RuntimeException("Handler not called for "
+                                    + ll.getName() + "("+ countAfter +")");
+                        }
                         hrb = handler.rb;
                         hrbName = handler.rbName;
                         if (name != null) {
+                            // if name is not null, then it implies that it
+                            // won't change, since setResourceBundle() cannot
+                            // replace a non null name.
+                            // Since we never set the resource bundle on 'll',
+                            // then ll must inherit its resource bundle [name]
+                            // from l - and therefor we should find it in
+                            // handler.rb/handler.rbName
                             if (!name.equals(hrbName)) {
                                 throw new RuntimeException("Unexpected bundle name: "
-                                        +hrb.getBaseBundleName());
+                                        +hrbName);
                             }
+                            // here we know that hrbName is not null so hrb
+                            // should not be null either.
                             if (!name.equals(hrb.getBaseBundleName())) {
                                 throw new RuntimeException("Unexpected bundle name: "
                                         +hrb.getBaseBundleName());
                             }
                         }
 
+                        // Make sure to refer to 'l' explicitly in order to
+                        // prevent eager garbage collecting before the end of
+                        // the test (JDK-8030192)
+                        if (!ll.getName().startsWith(l.getName())) {
+                            throw new RuntimeException("Logger " + ll.getName()
+                                    + "does not start with expected prefix "
+                                    + l.getName());
+                        }
+
                         getRBcount.incrementAndGet();
                         if (!goOn) break;
                         Thread.sleep(1);