Question 21
final class Complex {
private double re, im;
public Complex(double re, double im) {
this.re = re;
this.im = im;
}
Complex(Complex c)
{
System.out.println(\"Copy constructor called\");
re = c.re;
im = c.im;
}
public String toString() {
return \"(\" + re + \" + \" + im + \"i)\";
}
}
class Main {
public static void main(String[] args) {
Complex c1 = new Complex(10, 15);
Complex c2 = new Complex(c1);
Complex c3 = c1;
System.out.println(c2);
}
}
Question 22
class Point {
int m_x, m_y;
public Point(int x, int y) { m_x = x; m_y = y; }
public Point() { this(10, 10); }
public int getX() { return m_x; }
public int getY() { return m_y; }
public static void main(String args[]) {
Point p = new Point();
System.out.println(p.getX());
}
}
Question 23
1) Constructor name should be same as class name. 2) If you don\'t define a constructor for a class, a default parameterless constructor is automatically created by the compiler. 3) The default constructor calls super() and initializes all instance variables to default value like 0, null. 4) If we want to parent class constructor, it must be called in first line of constructor.
Question 24
package main;
class T {
int t = 20;
}
class Main {
public static void main(String args[]) {
T t1 = new T();
System.out.println(t1.t);
}
}
Question 26
Question 27
class Test
{ int count = 0;
void A() throws Exception
{
try
{
count++;
try
{
count++;
try
{
count++;
throw new Exception();
}
catch(Exception ex)
{
count++;
throw new Exception();
}
}
catch(Exception ex)
{
count++;
}
}
catch(Exception ex)
{
count++;
}
}
void display()
{
System.out.println(count);
}
public static void main(String[] args) throws Exception
{
Test obj = new Test();
obj.A();
obj.display();
}
}
Question 28
class Base extends Exception {}
class Derived extends Base {}
public class Main {
public static void main(String args[]) {
// some other stuff
try {
// Some monitored code
throw new Derived();
}
catch(Base b) {
System.out.println(\"Caught base class exception\");
}
catch(Derived d) {
System.out.println(\"Caught derived class exception\");
}
}
}
Question 29
class Main {
public static void main(String args[]) {
try {
throw 10;
}
catch(int e) {
System.out.println(\"Got the Exception \" + e);
}
}
}
Question 30
1) Every class is part of some package. 2) All classes in a file are part of the same package. 3) If no package is specified, the classes in the file go into a special unnamed package 4) If no package is specified, a new package is created with folder name of class and the class is put in this package.
There are 50 questions to complete.