code: public static void checkVerboseLogSetting() {
  		try {
  			AccessController.doPrivileged(new PrivilegedAction() {
  	            public Object run() {
  					String val = System.getProperty(Log.forceVerboseProperty);
  					if ((val != null) && (val.equalsIgnoreCase(Log.forceVerbosePropertyOnValue))) {
  						Log.setForcedVerboseOn();
  					}
  					
  					return null;
  	            }
  			});
  		} catch (Throwable e) {
  			// ignore, security failure - probably an applet
  		}
  	}
docs: Check if the system property org.newdawn.slick.verboseLog is set to true.
  If this is the case we activate the verbose logging mode