Here is an example of StringTokenizer class that accept the full name from the user and display the first name, middle name and last name.

import java.util.*;
public class GetMiddleName
{
       public static void main(String[] args) {
            Scanner input = new Scanner(System.in);
            System.out.println("Enter your full name: ");
            String fullName = input.nextLine();
            StringTokenizer stok = new StringTokenizer(fullName);
            String firstName = stok.nextToken();

            StringBuilder middleName = new StringBuilder();
            String lastName = stok.nextToken();
            while (stok.hasMoreTokens())
            {
              middleName.append(lastName + " ");
              lastName = stok.nextToken();
            }
            System.out.println("First Name: "+firstName);
            System.out.println("Middle Name: "+middleName.toString().trim());
            System.out.println("Last Name: "+lastName);
          }


}