Bug 170763 Log files are created even if the log level has been set to OFF or the log dir to null
Even if you set the log level to OFF (e.g. within the BIRT report viewer web application) empty log files are created in BIRT's log directory. The same is the case if the log directory has been set to null. If the directory does not exist, a stack trace is printed to System.err. This is due to the fact that org.eclipse.birt.report.engine.api.impl.EngineLogger sets up a java.util.logging.FileHandler no matter what. It shouldn't do this if the log level is OFF or the directory is null.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/EngineLogger.java
Logger logger = Logger.getLogger( BIRT_NAME_SPACE );
		assert (logger != null);
		
		if ( logLevel != null )
			logger.setLevel( logLevel );
				
		createLogFile( logger );
	}
	/**
	 * Stop BIRT Logging and close all of the handlers. This function should only by called by the main application that started BIRT.
	 * Note: Because of a Java API's bug, an additional .lck file will be created for each log file. 
	 * 		 Please see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4775533 for detail.    
	 */
	public static void stopEngineLogging()
	{
		Logger logger = Logger.getLogger( BIRT_NAME_SPACE );
		assert (logger != null);
		
		Handler[] handlers = logger.getHandlers();
		if ( (handlers != null) &&
			 (handlers.length > 0) )
		{
			for ( int i=0; i<handlers.length; i++ )
			{
				handlers[i].close();
				logger.removeHandler( handlers[i] );
			}
		}