It is not a `keyword` it is a `label` 




Usage: 

 label1:
 for(){
 label2:
 for(){
 if(condition1)
 break label1;//break outerloop
 
 if(condition2)
 break label2;//break innerloop
 }
 }

 - [Documentation ][1]
 [1]: http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.7