User Input

Here is the program with some additional details filled in, and some details that you are to fill in:

import java.util.Scanner;

class ComboLock
{
  public static void main ( String[] args )  
  {
    int lockFirst = 6, lockSecond = 12, 
        lockThird = 30;  // The combination
    int numb;            // a user-entered number

    Scanner scan = new Scanner( System.in );

    boolean correct = true;

    //First Number
    System.out.print("Enter first number: ");
    numb  = scan.nextInt();

    if (   )
      
      correct =  ;

    //Second Number

    //Third Number

    //Result
    if ( correct )
      System.out.println("Lock opens");
    else
      System.out.println("Lock does not open");
  }
}

The program uses variables lockFirst, lockSecond, and lockThird rather than using literal integer values so that the programmer can easily change the combination.