lecture

Binary patching of Java classes for fun (and profit)

The what/why/how of runtime binary patching of JAVA applications, frameworks and application servers to provide custom integration. We will follow the JRebel integration story from dirty bytecode insertions to readable Java code patches. The session is intended for advanced Java developers interested in patching or integrating with binary java applications.

We will look at the different problems that arise when doing runtime binary patching of different Java applications and frameworks.

Bytecode for discriminating developers

If you never goofed around with assembler or machine code Java bytecode can seem an obscure piece of low-level magic. But sometimes things go really wrong and understanding that bit may be what stands between you and solving the problem at hand. Looking to deepen you Java programming skills? Understanding bytecodes is necessary to solve performance issues, some classloading issues and to generate code at runtime. And some things you can do are just plain freakin' cool. This talk will introduce you the JVM and bytecode basics using live coding examples. It's my hope that you'll walk out armed for the next battle with low-level issues. From the basics, to more advanced gotchas: * How to obtain the bytecode listings * How to read the bytecode * How the language constructs are mirrored by the compiler: local variables, method calls, optimizations, autoboxing, exception handling, etc * insight to some bytecode manipulation libraries (ASM, Javassist)