please solve this question It is a discrete math problem Not

please solve this question. It is a discrete math problem. Not computer science.

Prove that it is possible to write a program P which: takes as input M, a java program runs forever, and prints out strings to the console for every x, if M(x) halts, then P(M) eventually prints out x for every x, if M(x) does NOT halt, then P(M) never prints out x

Solution

import java.util.*;
class Print
{
   String st;
   public static void main(String ss[])
   {
       Scanner sc = new Scanner(System.in);      
       Print pp = new Print();
       char ch;
       System.out.println(\"Enter a string: \");
       pp.st = sc.nextLine();
       System.out.println(\"Enter a Character: \");
       //Accept a character
       ch = sc.nextLine().charAt(0);
       //Calls the M method to check character halts
       pp.M(ch);
   }

   void M(char cha)
   {
       int c;
       System.out.println(\"Result: \ \");
       //Loops till the length of the string
       for(c = 0; c < st.length(); c++)
       {
           //If the character is available calls the P() method
           if(st.charAt(c) == cha)
               P(cha);
       }
   }
   //Display the character if it is available
   void P(char cc)
   {
       System.out.print(\" \" + cc);
   }
}

Output:

Enter a string:
This is a demo
Enter a Character:
s
Result:

s s