Strings is a part of google Guava librarys. Strings is Static utility methods pertaining to String or CharSequence instances.
Strings helps us to :

  1. Check Null Value
  2. Pad String
  3. Repeat String
  4. Check Prefix or Sufix

Let See The example code below :

And here are the results of our code snippet above:

Visit My Repository for full code
showimage

Reference
String Documentation