I need to be able to generate byte code from java source generated in memory. The problem I have using Javassist is that the compiler is not strong enough to flag compilation errors with line numbers and well-defined reasons. I don't want to use javac or Eclipse JDT because they require files to be written to disk - all my code is in memory and can't be written to disk. I realize Javassist is probably not the right tool for what I want to do. Anyone on this forum suggest any alternatives?