class file gets deleted

[Anthony.Green]

Hi, I'm having a strange error with Netbeans that I can't seem to figure
out. The code I'm writing is quite repetitive so I have a small program in
Netbeans which "writes" java code (prints it out to a text file) which I
then paste back into Netbeans for use as part of a large program. I've had
no problems with this approach until today, when I pasted the code back
into Netbeans and got the NoClassDefFoundError when attempting to run. An
internet search maintains that it is a problem with compiler setup or the
.class file cannot be found-and its the latter that's causing it, because
the .class file (from the build\classes directory) vanishes (i.e. gets
deleted) once I have pasted the code into a particular class I'm using.
The code is 7000 lines long, could it be that the class is too long?

Thanks for any help you can provide,

Anthony Green