Question: I was browsing through some of the base Java objects when I found a section of code surrounded by a `scan: {}` block. The following code is from the toLowerCase() method inside the String class.

```
scan: {
            for (firstUpper = 0 ; firstUpper < len; ) {
                char c = value[firstUpper];
                if ((c >= Character.MIN_HIGH_SURROGATE)
                        && (c <= Character.MAX_HIGH_SURROGATE)) {
                    int supplChar = codePointAt(firstUpper);
                    if (supplChar != Character.toLowerCase(supplChar)) {
                        break scan;
                    }
                    firstUpper += Character.charCount(supplChar);
                } else {
                    if (c != Character.toLowerCase(c)) {
                        break scan;
                    }
                    firstUpper++;
                }
            }
            return this;
        }

```

Could someone please explain what the `scan:{}` block is used for and where this syntax comes from? I've yet to see a colon after a word like this in Java unless used in a ternary operator.

Thanks!

Edit: Updated title to correctly match answered question.

Answer: 
You can set a label to break / or continue from within multiple loops deep.

Example

```
 outer:
 for(int i=...){
   for(int j=..){
     ...
     break outer; // leaves both loops   

   } 

 }

```
It is a `label`. It is a indicator for flow control.

If you look at your code, you see below

```
 break scan;

```

When this happens, the flow exits completely the `scan` block.

By the way, it can be any identifier, `scan` is not a keyword at all.