mock

[Shalini Srivastav]

I thought it wont compile as there is a JILL label which has no meaning.

while(true)
{
     uselesslabel:       //compile error 
}

I don't know how it is valid in mock question ?

[Gaurangkumar Khalasi]

Shalini Srivastav wrote:I thought it wont compile as there is a JILL label which has no meaning.

while(true)
{
     uselesslabel:       //compile error 
}

I don't know how it is valid in mock question ?

First of all, please UseAMeaningfulSubjectLine.

Label is always attached with a statement. So, when you are trying to use "uselesslabel:" a label without a statement, it will give you errors...

[Shalini Srivastav]

You are not correct.

while(true)  
{  
     uselesslabel:  System.out.println("statement :wont compile");    
}

[Gaurangkumar Khalasi]

Shalini Srivastav wrote:You are not correct.

while(true)  
{  
     uselesslabel:  System.out.println("statement :wont compile");    
}

You got an error??? Or What are you trying to say?

[Shalini Srivastav]

I don't know what did you mean by statement.

//1
int 1=0;
label1:
label2:
while(i<10){       //will work
i++;
}     
               
//2
int i=0;
while(i<10){     
i++;
label:               //wont work, reached end           
}

//3
int i=0;
while(i<10){
label1:
label2:
label3:
i++;                //will work 
}

//4
label:
while(true){}  //will work 

[Gaurangkumar Khalasi]

A statement in Java forms a complete command to be executed and can include one or more expressions.
or
A statement is a single "command" that is executed by the Java interpreter.

Different kinds of statements in java for example:
1). Declaration Statement (e.g. int value;)
2). Expression Statement (e.g. value=7;)
3). Control flow Statement (e.g. for(int i=0; i<10;i++) {} )
4). Null Statement (e.g. ; )

[Kedar Pethe]

Shalini Srivastav wrote:I thought it wont compile as there is a JILL label which has no meaning.

while(true)
{
     uselesslabel:       //compile error 
}

I don't know how it is valid in mock question ?

Add a semicolon(;) at the end of uselsesslabel: (ie- uselsesslabel:;)

Just by luck it compiles without errors... could somebody explain this???

[Nitish Bangera]

I am surprised how a topic which is not used at all in the Java world could ignite such a discussion. In OCPJP, labels are there only for the questions with labelled break. Application wise, labels are never used at all. This is a migration from C's jump statements.

Also Shalini, Gaurang's code is correct

while(true)  
{  
     uselesslabel:  System.out.println("statement :wont compile");    
}

This code runs and outputs the String inside the println.

The error is due to improper ending(without the semicolon) which actually makes the the closing bracket as a statement which is clearly an error and this is stated very specifically when you do a javac on the class file.