Java break and Labeled break Statement

Once the execution of a loop statement in a program starts, it keeps repeating the execution of loop instructions as far as a given condition is true. Sometimes it may be required to break the execution flow in between. To break the execution flow of a loop, java provides a keyword called as break. It can be used inside for, while, do while and switch statements only. As soon as a break statement encountered in a loop, the execution of that loop get's terminated and the control flow jumps to the next statements after the loop body. It is mostly used along with conditional statements(if, else). The syntax of break statement is:

 break;

Control flow diagram of break statement

Once the break statement is executed, the remaining statements which are after the break and within the loop are skipped. Java break statement has two forms, labeled and unlabeled. Following program shows unlabeled break statement.

break Statement program in Java

 class BreakStatement
   {
     public static void main(String [] args)
       {          
          for(int i=1; i<=5; i++)
            {
               if(i==4)
                 {
                    break;
                 }
               System.out.println("i = "+i);
            }  
          System.out.println("line after for loop");             
        }
   }

Output:

In above example, as soon as the value of i becomes 4, the break statement is executed and the control flow jumps to next line(System.out.println("line after for loop");) after the for loop, that is why value 4 and 5 is not printed.

If break statement is used inside any inner loop, it breaks only inner loop once it is executed and the execution flow moves to the next line after inner loop. The outer loop will be executed as usual.

 class InnerLoopBreakStatement
   {
     public static void main(String [] args)
       {          
          for(int i=1; i<=3; i++)
            {
               System.out.println("Outer loop i = "+i);
               for(int j=1; j<=5; j++)
                 {
                    if(j==3)
                      {
                         break;
                      }
                    System.out.println("j = "+j);
                 } 
             } 
           System.out.println("line after outer for loop");             
        }
   }

Output:

Labeled break Statement

A label is an identifier, from java SE 5 and above we can declare a set of statements with a label identifier. Labeled break statement allows programmer to break the execution of label statements.

 class LabeledBreakStatement
   {
     public static void main(String [] args)
       {          
          firstLable:  
             for(int i=1;i<=3;i++)
               { 
                  System.out.println("Outer loop i = "+i);    
                  secondLabel:  
                     for(int j=1;j<=5;j++)
                       {    
                          if(i==2 && j==2)
                            {    
                               break firstLable;    
                            }    
                          System.out.println(" j = "+j);    
                       }    
                }
           System.out.println("line after labeled break statement");               
        }
   }

Output:

In above example as soon as the value of i and j becomes 2 the statement break firstLable is executed which breaks the firstLable statements and the execution moves to the next line which is System.out.println("line after labeled break statement");

See java switch statement tutorial for how break statement is used with switch statement in java.