frontBack

Problem:

Given a string, return a new string where the first and last chars have been exchanged.

 

Test Cases:
frontBack("code") → "eodc"
frontBack("a") → "a"
frontBack("ab") → "ba"

Solution:

public String frontBack(String str) {
  if(str.length()>=2)
  {
    return str.charAt(str.length()-1)+str.substring(1,str.length()-1)+str.charAt(0);
  }
  return str;
}