A reference variable marked final cant reassigned to different object.The data with in object can be modified but the reference variable cannot be changed.

Based on my Understanding I have a created a code below where I am trying to reassign a new UserId of 155.As the Definition goes I am only trying to change data within the object. But the reference is same. 

```
public class FinalClass 
{   
    public static void main(String[] args)
    {
        ChildClass objChildClass = new ChildClass(); 
        objChildClass.UserId = 155;
    }
}

class ChildClass
{
    public static final int  UserId = 145;  
}

```

I believe I misunderstood the above concept.

Kindly explain the same with example.

Thanks for Reply.