Mcq On Java Garbage Collection

11. When is the B object, created in line 3, eligible for garbage collection?
void start() {
A a = new A();
B b = new B();
a.s(b);
b = null; /* Line 5 */
a = null; /* Line 6 */
System.out.println("start completed"); /* Line 7 */
}

A. after line 5
B. after line 6
C. after line 7
D. There is no way to be absolutely certain.

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12. How many objects are eligible for garbage collection after execution of line ?
public class Test
{
public static void main(String[] args)
{
m1(); // Line
}
static void m1()
{
Test t1 = new Test();
Test t2 = new Test();
} }

A. 0
B. 1
C. 2
D. 3

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13.after line 11 runs, how many objects are eligible for garbage collection?
class X2
{
public X2 x;
public static void main(String [] args)
{
X2 x2 = new X2(); /* Line 6 */
X2 x3 = new X2(); /* Line 7 */
x2.x = x3;
x3.x = x2;
x2 = new X2();
x3 = x2; /* Line 11 */
doComplexStuff();
}
}

A. 0
B. 1
C. 2
D. 3

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14. When is the Demo object eligible for garbage collection?
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();
}
}

A. After line 7
B. After line 8
C. After the start() method completes
D. When the instance running this code is made eligible for garbage collection.

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15. How many objects are eligible for garbage collection after execution of line 8?
public class Test
{
public static void main(String [] args)
{
Test t1 = new Test();
Test t2 = m1(t1); // line 6
Test t3 = new Test();
t2 = t3; // line 8
}
static Test m1(Test temp)
{
temp = new Test();
return temp;
}
}

A. 0
B. 1
C. 2
D. 3

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16. When is the Float object, created in line 3, eligible for garbage collection?
public Object m()
{
Object o = new Float(3.14F);
Object [] oa = new Object[l];
oa[0] = o; /* Line 5 */
o = null; /* Line 6 */
oa[0] = null; /* Line 7 */
return o; /* Line 8 */
}

A. just after line 5
B. just after line 6
C. just after line 7
D. just after line 8

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