@Override
            public void alert(GcData gcData) {
              System.err.println(
                  "GcTimeMonitor alert. Current GC time percentage = " +
                  gcData.getGcTimePercentage() +
                  ", total run time = " + (gcData.getGcMonitorRunTimeMs() / 1000) + " sec" +
                  ", total GC time = " + (gcData.getAccumulatedGcTimeMs() / 1000) + " sec");
            }
Simple 'main' to facilitate manual testing of the pause monitor.

This main function just leaks memory. Running this class will quickly
result in a "GC hell" and subsequent alerts from the GcTimeMonitor.
common/src/java/org/apache/hadoop/hive/common/GcTimeMonitor.java