void start() {
A a = n
Practice Garbage Collections –
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 */
}
Which statement is true?
Practice Garbage Collections –
Which statement is true?
Which statement is true?
Practice Garbage Collections –
Which statement is true?
Which statement is true?
Practice Garbage Collections –
Which statement is true?
What allows the programmer to destroy an object x ?
Practice Garbage Collections –
What allows the programmer to destroy an object x ?
class X2 {
public X2 x;
Practice Garbage Collections –
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();
}
}
after line 11 runs, how many objects are eligible for garbage collection?
public Object m()
{
Practice Garbage Collections –
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 */
}
When is the Float object, created in line 3, eligible for garbage collection?
public class X {
public
Practice Garbage Collections –
public class X {
public static void main(String [] args) {
X x = new X();
X x2 = m1(x); /* Line 6 */
X x4 = new X();
x2 = x4; /* Line 8 */
doComplexStuff();
}
static X m1(X mx) {
mx = new X();
return mx;
}
}
After line 8 runs. how many objects are eligible for garbage collection?
class Test {
private
Practice Garbage Collections –
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?
class Bar { }
class Test {
Practice Garbage Collections –
class Bar { }
class Test {
Bar doBar() {
Bar b = new Bar(); /* Line 6 */
return b; /* Line 7 */
}
public static void main (String args[]) {
Test t = new Test(); /* Line 11 */
Bar newBar = t.doBar(); /* Line 12 */
System.out.println("newBar");
newBar = new Bar(); /* Line 14 */
System.out.println("finishing"); /* Line 15 */
}
}
At what point is the Bar object, created on line 6, eligible for garbage collection?
class HappyGarbage01 {
Practice Garbage Collections –
class HappyGarbage01 {
public static void main(String args[]) {
HappyGarbage01 h = new HappyGarbage01();
h.methodA(); /* Line 6 */
}
Object methodA() {
Object obj1 = new Object();
Object [] obj2 = new Object[1];
obj2[0] = obj1;
obj1 = null;
return obj2[0];
}
}
Where will be the most chance of the garbage collector being invoked?
Which statement is true?
Practice Garbage Collections –
Which statement is true?
