Tell now I have studied that java uses pass-by-value but I am bit confused here

Question

public class Passing_Objects_to_Methods 
{
int id;
public Passing_Objects_to_Methods(int id) 
{
    this.id=id;
}
public static void swap(Passing_Objects_to_Methods b1,Passing_Objects_to_Methods b2)
{
    Passing_Objects_to_Methods temp;
    temp=b1;
    b1=b2;
    b2=temp;
}
public static void main(String []args)
{
    Passing_Objects_to_Methods obj1=new Passing_Objects_to_Methods(2);
    Passing_Objects_to_Methods obj2=new Passing_Objects_to_Methods(1);
    System.out.println("Before Swapping");
    System.out.println("Id of obj1 "+obj1.id);
    System.out.println("Id of obj2 "+obj2.id);
    swap(obj1, obj2);
    System.out.println("After Swapping");
    System.out.println("Id of obj1 "+obj1.id);
    System.out.println("Id of obj2 "+obj2.id);
}   

When I pass object and try to interchange it wont change outside the block since java is pass-by-value But

public class Passing_Objects_to_Methods_Part2 {
    int id;
    public Passing_Objects_to_Methods_Part2(int id) 
    {
        this.id=id;
    }
        
    public static void Swap(Passing_Objects_to_Methods_Part2 b1,Passing_Objects_to_Methods_Part2 b2)
    {
        int temp;
        temp=b1.id;
        b1.id=b2.id;
        b2.id=temp;
    }
    public static void main(String[] args)
    {
        Passing_Objects_to_Methods_Part2 obj1=new Passing_Objects_to_Methods_Part2(2);
        Passing_Objects_to_Methods_Part2 obj2=new Passing_Objects_to_Methods_Part2(1);
        System.out.println("Before Swapping");
        System.out.println("Id of obj1 "+obj1.id);
        System.out.println("Id of obj2 "+obj2.id);
        Swap(obj1, obj2);
        System.out.println("After Swapping");
        System.out.println("Id of obj1 "+obj1.id);
        System.out.println("Id of obj2 "+obj2.id);

    }
}

As I try to interchange The variables of objects it does change them Outside the block also.Please Tell me the reason.