Spring MVC debug A to Z

Question

BEFORE START

Let's say I put a debug point like below~!

  @RequestMapping("/test")
  public String test() {
      String char = "abcdEFGhIjQlmnopqrstuvwXYZ";

●     char.toLowerCase(); // pointed here.
  }

And what's inside of String class... ( this is an actual code snippet inside of String class )

.
.
.
public String toLowerCase()
{
    return toLowerCase(Locale.getDefault());
}
.
.
.

WHAT I WANT TO DO HERE

is that when debugging, pressing F5 (step into) on the debug point above takes me to the toLowerCase() method in String class. Currently in my development environment, this doesn't happen.

AND I WANT TO

hang on to these processes below and check every steps and inspect everything so that I can fully understand what's going on inside in Spring MVC application. Well I've read many docs about, so to speak, core classes of Spring MVC and studied its architecture. But what I can do by the efforts now is just to imagine what the proccesses would be like.

Time to make it concrete.

Is there any special configurations to do this?

Answer 1

I would put a breakpoint in one of my controller methods. Then I would "invoke" that method by a HTTP Request (from my browser).

Then I would inspect the stack trace (you can click on the stacktrace lines to jump to the implementation and also inspect the variables) or I would use "Step Return" (F7) to understand how the controller method is invoked.

This technique would not show you all the actions and additional stuff that is done before your controller method is invoked, but it would show you a straight line of invocations that end in your controller method.