WebView takes up high memory usage when browsing until it goes crashed

I have written a simple web browser program using webview by following the tutorials "Adding HTML Content to JavaFX Applications" by Alla Redko on http://download.oracle.com/javafx/2.0/webview/jfxpub-webview.htm and "Integrating JavaFX into Swing Applications" by Irina Fedortsova on http://download.oracle.com/javafx/2.0/swing/jfxpub-swing.htm.

The webview and GUI work fine for JavaFX Content and Swing Component, everything looks great. Anyway, the program crashes every time after hour long browsing.
As I found that by monitoring task manager in windows 7, when the program starts, it takes up memory usage and go up until as high as it crashes the program during browsing. The problem can be seen more obviously especially during browsing the google map.

I believe it has nothing to do with the coding part as I followed fully the tutorial above-mentioned. Yet I found no solution to pull down the memory usage.