Why is "out of range" not thrown for 'substring(startIndex, endIndex)'

In Java I am using the substring() method and I'm not sure why it is not throwing an "out of index" error.

The string abcde has index start from 0 to 4, but the substring() method takes startIndex and endIndex as arguments based on the fact that I can call foo.substring(0) and get "abcde".

Then why does substring(5) work? That index should be out of range. What is the explanation?

/*
1234
abcde
*/
String foo = "abcde";
System.out.println(foo.substring(0));
System.out.println(foo.substring(1));
System.out.println(foo.substring(2));
System.out.println(foo.substring(3));
System.out.println(foo.substring(4));
System.out.println(foo.substring(5));

This code outputs:

abcde
bcde
cde
de
e
     //foo.substring(5) output nothing here, isn't this out of range?

When I replace 5 with 6:

foo.substring(6)

Then I get error:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException:
    String index out of range: -1