Need help on java H/W. thanks

Prompt the user to input a string of even length, output a string made of the middle two chars, so the string "string" yields "ri". The string length will be at least 2. If the String is less than 2 or odd prompt the user and have the program loop back to the beginning. The program will end if the user enter an even String longer than 2 characters. Example Programs Please input a String: string ri Please input a String: code od