private static void checkDebug() {
    try {
      if (Boolean.getBoolean("gfAgentDebug")) {
        mx4j.log.Log.setDefaultPriority(mx4j.log.Logger.TRACE); // .DEBUG
      }
    } catch (VirtualMachineError err) {
      SystemFailure.initiateFailure(err);
      // If this ever returns, rethrow the error. We're poisoned
      // now, so don't let this thread continue.
      throw err;
    } catch (Throwable t) {
      // Whenever you catch Error or Throwable, you must also
      // catch VirtualMachineError (see above). However, there is
      // _still_ a possibility that you are dealing with a cascading
      // error condition, so you also need to check to see if the JVM
      // is still usable:
      SystemFailure.checkFailure();
      /* ignore */
    }
  }
Enables mx4j tracing if Agent debugging is enabled.
geode-core/src/main/java/org/apache/geode/admin/jmx/internal/AgentImpl.java