How to get the last characters in a String in Java, regardless of String size

Question

I'm looking for a way to pull the last characters from a String, regardless of size. Lets take these strings into example:

"abcd: efg: 1006746" "bhddy: nshhf36: 1006754" "hfquv: nd: 5894254" 

As you can see, completely random strings, but they have 7 numbers at the end. How would I be able to take those 7 numbers?

Edit:

I just realized that String[] string = s.split(": "); would work great here, as long as I call string[2] for the numbers and string[1] for anything in the middle.

Answer 1

How about:

String numbers = text.substring(text.length() - 7); 

That assumes that there are 7 characters at the end, of course. It will throw an exception if you pass it "12345". You could address that this way:

String numbers = text.substring(Math.max(0, text.length() - 7)); 

or

String numbers = text.length() <= 7 ? text : text.substring(text.length() - 7); 

Note that this still isn't doing any validation that the resulting string contains numbers - and it will still throw an exception if text is null.