description of bytecode obtained with the command javap -v {Whataver.class}

Since it's my first post on SO, let me clarify a little what was asked immediately after the first reply (I can't do it inside the thread because I lack reputation)

Every "command" here (iload_3, iload_1, pop, invokevirtual, etc) are opcodes. BCI are the numbers on the left.

45: invokevirtual #22 means, offset 45 bytes from wherever we're starting "invokevirtual" #22

"#" marks a constant in the constant pool 22 is 16 in hexadecimal, opcode invokevirtual is B6. In my particular compiled class the constant 22 is the call to println.

So the bytecode for those 3 things is this B6 00 16 B6 being invoke virtual, 00 I don't know xD and hex 16 is decimal 22

The 45 in the instruction, which is the bci means that at offset 45(2D) from where that stack begins (181) starts that instruction. 181 + 2D = 1AE

At offset 0 of byte 181 is the instruction 10, which is bipush, this is how it looks after javap

0: bipush