This is just the beginning. If you've gotten this far, then you understand how to read and write JVM code, and you understand how Java and other languages can be translated into bytecodes. Here are some suggestions for further reading.
[bib01entry01] The Java Language Specification, by and . Addison-Wesley <year>1996</year>.Simply the most comprehensive book on Java out there. It is the reference text that defines what Java programs are and what they mean. Despite its weighty subject, it is a lot of fun to read.
[bib01entry02] The Java Virtual Machine Specification, by and Addison-Wesley <year>1998</year>.The bible of Java virtual machine programming.