what is this? Variable?

[chronoz13]

public class BreakingLoop {
 
     public static void main(String[] args) {
 
         int count = 0;
         loop_one:
 
             for (int k=5;k < 100;k++) {
 
                 for (int j=3; j < 100; j++) {
 
                     if (j % 2 == 0) {
 
                         break;
                     }
 
                     if (k == 67) {
 
                         break loop_one;
 
                     }
                     count ++;
                 }
             }
 
         System.out.println(count);
     }
 }

i was searching some mild exercises on the net and i saw this one.. and one part intrigues me.
what is that

loop_one:

? the only thing i can notice and i dont know if my assumption is right..is, does it refer to the loops? and how come?
when i removed it.. my IDE gave me an error -

undefined Label

can anyone kindly give me some explanation about that.. i never encountered such one before
thanks

[helloworld922]

It's called a label. It's an old relic from way back when where you could simply "jump" to another section of code and start executing from there (via the infamous goto keyword). In Java, labels function a little differently. Technically goto is a defined keyword, but it doesn't do anything (and I think actually gives you a compile error). However, you could break/continue to a label. What that allows you to do is break or continue up multiple blocks.

label1:
for(int i = 0; i < 5; ++i)
{
    for(int j = 0; j < 5;++j)
    {
        break label1; // breaks out of both loops, not just the inner loop
    }
    System.out.println("this will never execute");
}

[chronoz13]

thanks for the clear answer