Practice Objects and Collections –
What will be the output of the program?
class Super {
public int i = 0;
public Super(String text) /* Line 4 */ {
i = 1;
}
}
class Sub extends Super {
public Sub(String text) {
i = 2;
}
public static void main(String args[]) {
Sub sub = new Sub("Hello");
System.out.println(sub.i);
}
}
Practice Objects and Collections –
What will be the output of the program?
public class A {
void A() /* Line 3 */ {
System.out.println("Class A");
}
public static void main(String[] args) {
new A();
}
}
Which three statements are true?
Practice Objects and Collections –
Which three statements are true?
Practice Threads –
What will be the output of the program?
public class Test107 implements Runnable {
private int x;
private int y;
public static void main(String args[]) {
Test107 that = new Test107();
(new Thread(that)).start();
(new Thread(that)).start();
}
public synchronized void run() {
for(int i = 0; i < 10; i++) {
x++;
y++;
System.out.println("x = " + x + ", y = " + y); /* Line 17 */
}
}
}
/* Missing Statement ? */
publ
Practice Package –
/* Missing Statement ? */
public class foo {
public static void main(String[]args)throws Exception {
java.io.PrintWriter out = new java.io.PrintWriter();
new java.io.OutputStreamWriter(System.out,true);
out.println("Hello");
}
} What line of code should replace the missing statement to make this program compile?
package testpkg.p1;
public cla
Practice Package –
package testpkg.p1;
public class ParentUtil {
public int x = 420;
protected int doStuff() {
return x;
}
}
package testpkg.p2;
import testpkg.p1.ParentUtil;
public class ChildUtil extends ParentUtil {
public static void main(String [] args) {
new ChildUtil().callStuff();
}
void callStuff() {
System.out.print("this " + this.doStuff() ); /* Line 18 */
ParentUtil p = new ParentUtil();
System.out.print(" parent " + p.doStuff() ); /* Line 20 */
}
} which statement is true?
Practice Inheritance –
What will be the output of the program?
import java.util.*;
public class NewTreeSet2 extends NewTreeSet { //line 2
public static void main(String [] args) {
NewTreeSet2 t = new NewTreeSet2();
t.count();
}
}
protected class NewTreeSet { //line 8
void count() {
for (int x = 0; x < 7; x++,x++ ) {
System.out.print(" " + x);
}
}
}
Practice Inheritance –
What will be the output of the program?
class Base {
Base() {
System.out.print("Base");
}
}
public class Alpha extends Base {
public static void main(String[] args) {
new Alpha(); /* Line 12 */
new Base(); /* Line 13 */
}
}
Practice Inheritance –
What will be the output of the program?
class A {
final public int GetResult(int a, int b) {
return 0;
}
}
class B extends A {
public int GetResult(int a, int b) {
return 1;
}
}
public class Test {
public static void main(String args[]) {
B b = new B();
System.out.println("x = " + b.GetResult(0, 1));
}
}
Practice Inheritance –
What is the output of the following code ?
class A {
public int i;
protected int j;
}
class B extends A {
int j;
void display() {
super.j = 3;
System.out.println(i + " " + j);
}
}
class Output {
public static void main(String args[]) {
B obj = new B();
obj.i = 1;
obj.j = 2;
obj.display();
}
}
Practice Inheritance –
What is the output of the following program ?
class A {
int i;
void display() {
System.out.println(i);
}
}
class B extends A {
int j;
void display() {
System.out.println(j);
}
}
class inheritance_demo {
public static void main(String args[]){
B obj = new B();
obj.i=1;
obj.j=2;
obj.display();
}
}class Boo {
Boo(String s
Practice Inner Classes –
class Boo {
Boo(String s) {
}
Boo() {
}
}
class Bar extends Boo {
Bar() {
}
Bar(String s) {
super(s);
}
void zoo() {
// insert code here
}
} which one create an anonymous inner class from within class Bar?
Which is true about an anonymous inner class?
Practice Inner Classes –
Which is true about an anonymous inner class?
Practice Inner Classes –
What will be the output of the program?
public abstract class AbstractTest {
public int getNum() {
return 45;
}
public abstract class Bar {
public int getNum() {
return 38;
}
}
public static void main (String [] args) {
AbstractTest t = new AbstractTest() {
public int getNum() {
return 22;
};
AbstractTest.Bar f = t.new Bar() {
public int getNum() {
return 57;
}
};
System.out.println(f.getNum() + " " + t.getNum());
}
}
Practice Inner Classes –
What will be the output of the program?
public class TestObj {
public static void main (String [] args) {
Object o = new Object() /* Line 5 */ {
public boolean equals(Object obj) {
return true;
}
} /* Line 11 */
System.out.println(o.equals("Fred"));
}
}