Pfthb

Hi I am new to Java OOP and I have some problems in running the program

The problem is there is no output and the loop never stops.

This is my Main.java

public class Main 

 public static void main(String args) 

 Dice firstDie = new Dice();
 Dice secondDie = new Dice();
 do 
 count++;
 if(firstDie==secondDie )
 same=true;
 System.out.println("It took "+count+ " times " + firstDie.getValue() + " and " + secondDie.getValue());
 
 
 while(!same);
 

and this is my Dice.java

public class Dice 
 private int value;
 public Dice() 
 value = (int)(Math.random()*6)+1;
 public int getValue() return value; 

in my Main.java class when I write int count = 0; and boolean same = false; the loop never ends.

Probably you have to compare the value firstDie.getValue() and secondDie.getValue().

What you are trying to do is compare the 2 instances of class Dice . When you compare those, unless they are the same object, it cannot be same.
Hence, same is not made true at all and this goes to a loop.

For more info, please refer, equals() method in java because that is what is called when two instances/objects are compared.

Edit:
Even if you try below code snippet of do-while (ie. compare the value firstDie.getValue() and secondDie.getValue(),

do 
 count++;
 int first = firstDie.getValue();
 int sec = secondDie.getValue();
 System.out.println(first+ " "+sec);
 if(first==sec )
 same=true;
 System.out.println("It took "+count+ " times " + first + " and " + sec);
 
 
 while(!same);

It still goes to loop because of the fact that the value of Dice class is set only once i.e. in constructor.
So the ideal way is to write,

public Dice() 
 value = 0;
 public int getValue() return (int)(Math.random()*6)+1; }

You are comparing the classe's instances and not the values stored within them.
Notice that on your println you are referring to each of the dices values (which is what you want to compare and have match), but on your comparison you are checking the objects.

Since they are 2 different instances they will never match, and therefore there will be no output and the loop never stops.

try firstDie.getValue() == secondDie.getValue() instead of firstDie== secondDie

You are checking for the two instances to be equal if you say firstDie== secondDie. These two are never equal.