Javassist to ASM

[dimzon]

What does you think about migration from Javassist to ASM? I can help You to rewrite bytecode generation procedures.

[brettwooldridge]

What is the advantage?

[dimzon]

1. less dependency size
2. faster initialization (javassist need to parse string containing java code)

anyway it's just proposal

[brettwooldridge]

While I agree it requires a small dependency, the level at which bytecode generation occurs is simply too low for me. I don't think generating code at the bytecode level such as this:

MethodNode mn = new MethodNode(...);
InsnList il = mn.instructions;
il.add(new VarInsnNode(ILOAD, 1));
LabelNode label = new LabelNode();
il.add(new JumpInsnNode(IFLT, label));
il.add(new VarInsnNode(ALOAD, 0));
il.add(new VarInsnNode(ILOAD, 1));
il.add(new FieldInsnNode(PUTFIELD, "pkg/Bean", "f", "I"));
LabelNode end = new LabelNode();
il.add(new JumpInsnNode(GOTO, end));
il.add(label);
il.add(new FrameNode(F_SAME, 0, null, 0, null));
il.add(new TypeInsnNode(NEW, "java/lang/IllegalArgumentException"));
il.add(new InsnNode(DUP));
il.add(new MethodInsnNode(INVOKESPECIAL,
          "java/lang/IllegalArgumentException", "<init>", "()V"));
il.add(new InsnNode(ATHROW));
il.add(end);
il.add(new FrameNode(F_SAME, 0, null, 0, null));
il.add(new InsnNode(RETURN));
mn.maxStack = 2;
mn.maxLocals = 2;

... leads to particularly readable or maintainable code. I'm sure ASM has its place, for example when writing bytecode compilers, but I don't think it is a particularly good for the code generation needs of HikariCP.