java 进一法,如何在Eclipse中进入一个核心的java类方法？

Hi I am going to dig a little more in Java so I would like to see how the program executed in the core class. For example, I would like to know how String.chatAt() is implemented, so I set breakpoint and tried to step into with debug mode. But I failed, I set bp at the second line when the program hit it, I used step into it still continue to the third line.

String a = "1231231241241";

char b = a.charAt(0);

System.out.println(b);

I think it should go into the source and show "no source found" and then give me a chance to attach the source file, right? But why it cannot get in? I can only use ctrl+right click on a method to get into source and attach.

解决方案

It might be that your Eclipse is not setup to run with JDK, it might run with JRE instead.

Check this link.

Also, I might suggest you to try and use Maven for your Java projects management, it makes the life so much easier, when you get a grasp of it.