} file.mkdir( );
}
	public static String createSessionTempDir( String tempRootDirStr )	{		String sessionTempDirStr;		final String prefix = "session_";		synchronized ( cacheCounter )		{			//Here we use complex algorithm so that to avoid the repeating of 			//dir names in 1.same jvm but different threads 2.different jvm.			sessionTempDirStr = tempRootDirStr					+ File.separator + prefix + System.currentTimeMillis( )					+ cacheCounter.intValue( );			cacheCounter = new Integer(cacheCounter.intValue( )+1);			File file = new File( sessionTempDirStr );						int i = 0;			while ( file.exists( ) )			{				i++;				sessionTempDirStr = sessionTempDirStr + "_" + i;				file = new File( sessionTempDirStr );			}			file.mkdir( );		}		return sessionTempDirStr;	}