If you don't need to make an interface, it's console input and output. Of course, you need a scanner for console input.

Scanner s = new scanner (system. in);

System.out.println ("Please enter string length:");

int len 1 = s . nextint()；

System.out.println ("Please enter a string:");

string str 1 = s . next line()；

System.out.println ("Please enter string length:");

int len 2 = s . nextint()；

System.out.println ("Please enter a string:");