What is "bci" while debugging in jdb?

While debugging with jdb on the command line, it shows me a status line after each step that looks like this:

Step completed: "thread=main", [class name].[method], line=10 bci=20

What is bci and how can it be 开发者_如何学编程useful to me?

It means byte code index . A single line, even a single Java statement, may translate to several bytecode instructions. The byte code index tells you which bytecode instruction was executed.