why we use this keyword in java code example

Example 1: how to use the this keyword in java

class Other{
    public double num;
    public Other(int num){
        this.num = num;
        System.out.println(num);
      	//print 5 to the console
    }
}

class scratch{
    public static void main(String[] args) {
        Other method = new Other(5);
        System.out.println(method.num);
      	//prints 5.0 to the console
    }
}

Example 2: this keyword in java

// java program using ‘this’ keyword
class Demo
{
   int m;
   int n;
   public void setValue(int m, int n)
   {
      // java this keyword
      this.m = m;
      this.n = n;
   }
   public void showValue()
   {
      System.out.println("Value m = " + m);
      System.out.println("Value n = " + n);
   }
}
public class ThisExample
{
   public static void main(String[] args)
   {
      Demo obj = new Demo();
      obj.setValue(5,6);
      obj.showValue();
   }
}