Q1:

class Test 
{  
    private Demo d; 
    void start() 
    {  
        d = new Demo(); 
        this.takeDemo(d); /* Line 7 */
    } /* Line 8 */
    void takeDemo(Demo demo) 
    { 
        demo = null;  
        demo = new Demo(); 
    } 
}

When is the Demo object eligible for garbage collection?

ANS:A - After line 7

Option D is correct. By a process of elimination. Option A is wrong. The variable d is a member of the Test class and is never directly set to null. Option B is wrong. A copy of the variable d is set to null and not the actual variable d. Option C is wrong. The variable d exists outside the start() method (it is a class member). So, when the start() method finishes the variable d still holds a reference.