Thread: String out of bound exception

The -2 is the value of the index that was out of bounds.

Hello,

I would like to provide an example that will clarify this exception but before that we need to look at the substring(int beginIndex, int endIndex) method. The two method parameters int beginIndex and int endIndex have a key difference:

beginIndex is 0 based
endIndex is 1 based

And here is an example to illustrate this:

public static void main(String[] args) {
     String str = "012345";
     System.out.println(str.substring(0, 1);
}

This will print "0" and here is why

0 based indexes of our string:
String str = "012345";
INDEXES 012345

1 based indexes of our string:
String str = "012345";
INDEXES 123456

you can play with the indexes and you can even say str.substring(3, 3) which will print an empty string "".
Now to go back to our exception java.lang.StringIndexOutOfBoundsException -2
This exception will be thrown when the endIndex is beginIndex = endIndex - 2 which in our case is str.substring(3, 1)

The following code will throw java.lang.StringIndexOutOfBoundsException -2:

public static void main(String[] args) {
     String str = "012345";
     System.out.println(str.substring(3, 1);
}

I hope this helps.

Regards
Alin