A few JavaOne’s ago, I saw a presentation about visualgc. It’s a visual monitoring on heap usage in a JVM. It’s a cool tool for those who prefer to look at screen full of animating charts rather than scrolling numbers. See below for a screen capture. It’s not bundled with Java SE, so you will have grab it from here. Once you downloaded it, upload it to the target system under stress, then you can run it with a command similar to the following:
You should see 3 windows pop up that looks just like the image below. If you forward the display to another machine, it will add network traffic. You might not want to do this if your network is under heavy load. Try jstat instead.