Exception in thread "main" java.lang.NoClassDefFoundError

hello, when i try to write a program, and run it(after compiling), it gives me this error.do i need to set my "classpath" or something?thank you,MORPG_programmer
[189 byte] By [MORPG_programmera] at [2007-10-2 13:04:46]
# 1
figured it out, i took away the .class off the end of it.
MORPG_programmera at 2007-7-13 10:28:01 > top of Java-index,Developer Tools,Debugging and Profiling Tool APIs...