In my post above, I said that your OS tries to use all available physical RAM. However, you have ample RAM that is not allocated to any particular task. The fact that you have a lot of RAM allocated to Java should not be an issue. What is an issue, however, is that Java is running in the first place. Java does not run unless you have one or more Java-based applications running. The most popular Java-based applications that I know are Bittorrent clients. Are you running a Bittorrent client?