Java Garbage Collection Statistics

Anyone who has done even a moderate  sized project in java knows about the GC hell that comes with it. Its simple enough to have those GC statistics from the beginning rather than adding later and waiting for the process to run into GC issues. Here’s the piece that I typically add to the process and then fire up the log4J levels when the process shows signs of GC troubles.

private final ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1); // single thread for logging
//in your method - initialize the logger
executor.scheduleWithFixedDelay(gcStatLogger, 60000, 60000, TimeUnit.MILLISECONDS ); // log every minute

private class GCStatLogger implements Runnable {

@Override
public void run() {
 logGCStats();
}

private void logGCStats() {
 long gcCount = 0;
 long gcTime = 0;
 for(GarbageCollectorMXBean gc :ManagementFactory.getGarbageCollectorMXBeans()) {
   long count = gc.getCollectionCount();
   if(count >=0){
    gcCount += count;
   }

   long time = gc.getCollectionTime();
   if(time >=0) {
    gcTime += time;
   }
  }

  log.debug("Total Garbage Collections: " + gcCount );
  log.debug("Total Garbage Collection Time (ms): "+ gcTime);
 }
}