Multiple open and close curly brackets inside method. - Java

Question

 public class MyTestClass {      public static void main(String[] args) {         new MyTestClass().myMethod();     }      public void myMethod(){         {         //do something          }         {             //do something          }         {             //do something          }     }//method close  }//class close 

What is the benefit of doing this? I have seen this kind of code.

Answer 1

It is not common practice to do this kind of thing, and I wouldn't do it normally.

They are defined as Blocks in the JLS, here.

Those inner blocks ( i.e. { ... } ) can serve a couple of purposes:

• Blocks limit the scope of any variables declared within them; e.g.

  public void foo() {     int i = 1;     {          int j = 2;     }     // Can't refer to the "j" declared here.  But can declare a new one.     int j = 3; } 

  However, I wouldn't recommend doing this. IMO, it's better to use different variable names OR refactor the code into smaller methods. Either way, most Java programmers would regard the { and } as annoying visual clutter.

• Blocks can be used to attach labels.

  HERE : {     ...     break HERE;  // breaks to the statement following the block     ... } 

  However, in practice you hardly ever see labelled break statements. And because they are so unusual, they tend to render the code less readable.

Answer 2

public void stuff() {   int i = 48;    {      int i = 21;     System.out.println(i); // prints 21   }   System.out.println(i); // prints 48 } 

Basically, it's a way to create scopes smaller than entire function... Benefit?.. have the people stare at your code longer before they understand it... IMO it's bad style and should be avoided