java.lang.OutOfMemoryError: Java heap space?

HI, i tried to embed an applet in a HTML document, but when i opened the HTML page, the applet was notinited. I opened java console and only this "java.lang.OutOfMemoryError: Java heap space" is written there...Can someone tell me what it means by "java heap space"?
[287 byte] By [meteora] at [2007-10-2 11:23:38]
# 1
This search list contains much information on the subject, both what is it and how to use it, and what is causing the error. http://www.google.com/search?num=100&hl=en&lr=lang_en&c2coff=1&q=java+%22heap+space%22
ChuckBinga at 2007-7-13 4:27:51 > top of Java-index,Developer Tools,Debugging and Profiling Tool APIs...