public void visitVarInsn(final int opcode, final int var) {
        // Label currentBlock = this.currentBlock;
        // adds the instruction to the bytecode of the method
        if (var < 4 && opcode != Opcodes.RET) {
            int opt;
            if (opcode < Opcodes.ISTORE) {
                /* ILOAD_0 */
                opt = 26 + ((opcode - Opcodes.ILOAD) << 2) + var;
            } else {
                /* ISTORE_0 */
                opt = 59 + ((opcode - Opcodes.ISTORE) << 2) + var;
            }
            code.putByte(opt);
        } else if (var >= 256) {
            code.putByte(196 /* WIDE */).put12(opcode, var);
        } else {
            code.put11(opcode, var);
        }
    }
Maximum number of local variables for this method.
src/main/java/com/alibaba/fastjson/asm/MethodWriter.java