IDEA breakpoint debugging (debug)

Table of contents

4. How to look at the source code when debugging

5. How to directly execute to the next breakpoint F9

6. Use breakpoint debugging to view the dynamic binding mechanism

1. Introduction to breakpoint debugging

Breakpoint debugging refers to setting a breakpoint on a certain line of the program. When debugging, the program will stop when it runs to this line, and then you can debug step by step. During the debugging process, you can see the current value of each variable. If something goes wrong , when debugging to the wrong line of code, the error will be displayed and stop. Analyze to find this bug.

In the process of breakpoint debugging, it is the running state, and it is executed according to the running type of the object.

Breakpoint debugging is a skill that programmers must master. It can help us view the execution process of the underlying java source code and improve the programmer's Java level.

Commonly used shortcut keys for breakpoint debugging

F7: jump into the method

F8: Execute code line by line . (Key analysis)

shift+F8: Jump out of the method

2. F8 execute code line by line

code (2-1)

public class Text1 {
    public static void main(String[] args) {
        int sum=0;
        for (int i = 1; i <= 10; i++) {
            sum+=i;
        }
        System.out.println(sum);
    }
}

Demo:

F8 execute code line by line

3. Debug encounter exception

Array out of bounds exception

code (3-1)

public class Text {
    public static void main(String[] args) {
        int[] arr={1,2,3};
        for (int i = 0; i <= arr.length; i++) {
            System.out.println(arr[i]);
        }
    }
}

Demo:

Array out of bounds exception

4. How to look at the source code when debugging

Use F7: You can't see the source code when you jump into the method . If you want to see the source code, I provide two methods.

method 1:

Use shortcut keys: alt+shift+F7;

Method 2:

Configuration: Setting->Build, Execution, Deployment->Debugger->Stepping, uncheck java.*, javax.* in Do not step into the classes, and others are optional.

How to debug and see the source code configuration

  public static void main(String[] args) {
        int[] arr={0,-1,100,6,7};
        Arrays.sort(arr);
        for (int i = 0; i < arr.length; i++) {
            System.out.println(arr[i]);
        }

Code (4-1)

See the source code for the demo :

see source code demo

Don't want to read shift+F8: jump out method

5. How to directly execute to the next breakpoint F9

code (5-1)

 public static void main(String[] args) {
        int[] arr={0,-1,100,6,7};
        Arrays.sort(arr);
        for (int i = 0; i < arr.length; i++) {
            System.out.println(arr[i]);
        }

        System.out.println("a");
        System.out.println("b");
        System.out.println("c");
        System.out.println("e");
        System.out.println("f");
        System.out.println("g");
        System.out.println("h");
    }

Demo:

How to execute directly to the next breakpoint

6. Use breakpoint debugging to view the dynamic binding mechanism

Code (6-1)

public class Text {
    public static void main(String[] args) {
        A a=new B();
        a.a();
    }
}

class A{
    public void a(){
        ab();
    }
    public void ab(){
        System.out.println("class A的方法");
    }
}

class B extends A{
  public void ab(){
      System.out.println("class B的方法");
  }
}

Demo:

Use breakpoint debugging to view the dynamic binding mechanism

The above is my personal sharing, if you have any questions, welcome to discuss! ! !

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