package autobox;
public class AutoBoxExample {
public static void main(String[] args) {
// TODO Auto-generated method stub
int i=10;
Integer i1=new Integer(i);//boxing
Integer i2=20;//boxing
int i3=i2;//unboxing
System.out.println(i1);
}
}
output:
------
>>>Final
package Enumpackage;
public class enumexampleagain {
enum days{mon(10),tue,wed(20),thu,fri(30),sat,sun(100);
private int result;
days(){
System.out.println("default constructor of days");
}
days(int i){
this.result=i;
System.out.println("This day as some value "+this.result);
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
for(days d:days.values()){
System.out.println(d);
}
if(days.mon==days.tue){
System.out.println("Do something different");
}
else{
System.out.println("everyday is a new day");
}
}
}
output:
This day as some value 10
package Threadsdeamon;
public class mainclass {
public static void main(String[] args) {
// TODO Auto-generated method stub
Thread t=new Thread1();
Runnable t2=new Thread2();
t.setDaemon(true);
t.start();
new Thread(t2).start();
if(t.isDaemon()){
System.out.println("Daemon thread is still alive");
}
}
}
>>>
package Threadspriority;
public class mainclass {
public static void main(String[] args) {
// TODO Auto-generated method stub
Thread t=new thread1();
Runnable r=new thread2();
t.start();
new Thread(r).start();
System.out.println(t.getName());
System.out.println("Priority of the thread by default"+t.getPriority());
t.setPriority(t.MIN_PRIORITY);
System.out.println("Priority of the thread after setting "+t.getPriority());
t.setPriority(t.MAX_PRIORITY);
System.out.println("Priority of the thread after setting "+t.getPriority());
}
}
>>>
thread1.java
package Threadsexample;
public class thread1 extends Thread {
synchronized public void run(){
System.out.println("thread one");
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
notify();
}
}
thread2,java
package Threadsexample;
public class thread2 implements Runnable{
@Override
public void run() {
// TODO Auto-generated method stub
System.out.println("Thread 2");
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
mainclass.java
package Threadsexample;
public class mainclass {
public static void main(String[] args) {
// TODO Auto-generated method stub
Thread t=new thread1();
Runnable r=new thread2();
t.start();
new Thread(r).start();
System.out.println(t.getName());
}
}
>>>
thread1.java
package Threadsexample;
public class thread1 extends Thread {
public void run(){
System.out.println("thread one");
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
thread2.java
package Threadsexample;
public class thread2 implements Runnable{
@Override
public void run() {
// TODO Auto-generated method stub
System.out.println("Thread 2");
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
mainclass.java
package Threadsexample;
public class mainclass {
public static void main(String[] args) {
// TODO Auto-generated method stub
Thread t=new thread1();
Runnable r=new thread2();
t.start();
try {
t.join();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
new Thread(r).start();
System.out.println(t.getName());
}
}
output :
thread1.java
package awesomeThreads;
public class thread1 extends Thread{
public void run(){
for(int i=0;i<3;i++){
System.out.println("First Thread");
}
try {
Thread.sleep(10000);
System.out.println("First Thread in sleeping mode");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
thread2.java
package awesomeThreads;
public class thread2 implements Runnable {
@Override
public void run() {
// TODO Auto-generated method stub
System.out.println("Seccond Thread");
try {
Thread.sleep(5000);
System.out.println("second Thread in sleeping mode");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
thread3.java
package awesomeThreads;
public class thread3 extends Thread{
public void run(){
for(int i=0;i<3;i++){
System.out.println("third Thread");
}
try {
Thread.sleep(2000);
System.out.println("Third Thread in sleeping mode");
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
mainclass.java
package awesomeThreads;
public class mainclass {
public static void main(String[] args) {
// TODO Auto-generated method stub
Thread t1=new thread1();
Runnable r2=new thread2();
Thread t3=new thread3();
t1.start();
new Thread(r2).start();
t3.start();
}
}
Output:
protectedclass.java
package p1;
public class protectedclass {
int i =10;
private int privatev=100;
protected int protectedv=1000;
public int publicv=10000;
}
subclass.java
package p1;
public class subclass extends p1.protectedclass {
subclass(){
System.out.println("access default variable "+i);
//System.out.println("access to private variable "+privatev);//private cannot be accessed outside the class
System.out.println("access to protected variable "+protectedv);
System.out.println("acces to public variable "+publicv);
}
}
nonsubclass.java
package p1;
public class nonsubclass {
nonsubclass(){
protectedclass p=new protectedclass();
System.out.println("access default variable "+p.i);
//System.out.println("access to private variable "+p.privatev);//private cannot be accessed outside the class
System.out.println("access to protected variable "+p.protectedv);
System.out.println("acces to public variable "+p.publicv);
}
}
Different package p2 protectedclass.java
package p2;
public class protectedclass extends p1.protectedclass{
protectedclass(){
//System.out.println("access default variable "+i);default access in not valid outside the package
//System.out.println("access to private variable "+privatev);//private cannot be accessed outside the class
System.out.println("access to protected variable "+protectedv);
System.out.println("acces to public variable "+publicv);
}
}
nonsubclass.java
package p2;
public class nonsubclass {
nonsubclass(){
p1.protectedclass p2=new p1.protectedclass();
//System.out.println("access default variable "+p2.i);//does not work in different package
//System.out.println("access to private variable "+privatev);//private cannot be accessed outside the class
//System.out.println("access to protected variable "+p2.protectedv);//proctected does not work in non subclasses
System.out.println("acces to public variable "+p2.publicv);
}
}
>>>FinalInterestCalculation.java package InheritanceExample; public class InterestCalculation { public int amount; public String category; InterestCalculation(String category, int amount) { this.category = category; this.amount = amount; } void interestratecalculation() { System.out.print("For " + this.category + " and for this amount " + this.amount); } }Adult.java package InheritanceExample; public class Adult extends InterestCalculation { private int interestrate; Adult(String category, int amount){ super(category,amount); } void interestratecalculation(){ if(amount<=1000){ interestrate=8; }else{ interestrate=9; } super.interestratecalculation(); System.out.println(" The interest rate is "+interestrate); } }Senior.java package InheritanceExample; public class Senior extends InterestCalculation { private int interestrate; Senior(String category, int amount){ super(category,amount); } void interestratecalculation(){ interestrate=10; super.interestratecalculation(); System.out.println(" The interest rate is "+interestrate); } }Output:mainClass.java package InheritanceExample; public class MainClass { public static void main(String[] args) { // TODO Auto-generated method stub Adult adultobj=new Adult("adult",1000); Adult adultobj1=new Adult("adult",1001); Senior seniorobj=new Senior("senior",1000); adultobj.interestratecalculation(); adultobj1.interestratecalculation(); seniorobj.interestratecalculation(); } }
For adult and for this amount 1000 The interest rate is 8
For adult and for this amount 1001 The interest rate is 9
For senior and for this amount 1000 The interest rate is 10
>>>
------------------------------------------------------------------------------------------------------------
package Example1;
import java.util.Arrays;
public class StringOperations {
public static void main(String[] args) {
// TODO Auto-generated method stub
String name="Albert Einstein";
//CharAt
System.out.println("Character at "+name.charAt(3));
//uppercase;
System.out.println("Uppercase "+name.toUpperCase());
//concat
System.out.println(name.concat("ka"));
System.out.println(name);
//equals and equalsignorecase
if(name.equals("Albert Einstein")){
System.out.println("its is true");
}
if(name.equalsIgnoreCase("Albert Einstein")){
System.out.println("ignores the case ");
}
//string contains
System.out.println("Contains the string " +name.contains("ber"));
//index of
System.out.println("Index of e is "+name.indexOf("e"));
//length of the string
System.out.println("length of String is "+name.length());
//Replace
System.out.println("Repalce string "+name.replace("A", "Dr A"));
//creation of string builder
StringBuilder names=new StringBuilder("Charles Darwin");
//append operation
System.out.println("Uppercase "+names.append("ka"));
System.out.println(names);
//capacity
System.out.println(names.capacity());
}
}
output:
package Example1;
import java.util.LinkedList;
public class LInkedList {
public static void main(String[] args) {
// TODO Auto-generated method stub
LinkedList linkedlistone=new LinkedList();//gerneric linkedlist
LinkedList names=new LinkedList();//LinkedList specific to String
//adding elements
names.add("Jill");
names.add("Jack");
names.add("Roy");
//Display elements
for(String lists:names){
System.out.println(lists);
}
//get a particular index
System.out.println("Get the list as the index mentioned "+ names.get(2));
//Get the first value
System.out.println("Get the first value "+names.getFirst());
//Get the last value
System.out.println("Get the last value "+names.getLast());
//copy of the linkedlist
LinkedList newlist=new LinkedList(names);
System.out.println("New linked list same as names "+newlist.toString());
//check if a element exist
if(newlist.contains("Jill")){
System.out.println("Jill is present in the list");
}
//Check all as the othe list
if(newlist.containsAll(names)){
System.out.println("Both the list matches");
}
//index
System.out.println("Return the index value "+newlist.indexOf("Jack"));
//peek - returns the first element
System.out.println(newlist.peek());
//Poll - returns teh first element and delete it from the list
System.out.println(newlist.poll());
for(String display:newlist){
System.out.println("This is the element in the newlist "+display.toString());
}
//push
newlist.push("Jack");
newlist.push("derek");
System.out.println(newlist.toString());
//clear
newlist.clear();
System.out.println(newlist.toString());
}
}
output:
package Example1;
import java.util.ArrayList;
import java.util.Iterator;
public class ArrayList1 {
public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList newarray=new ArrayList();
newarray.add("John");
newarray.add("Kevin");
// Iterator ite=newarray.iterator();
// while(ite.hasNext()){
// System.out.println(ite.next());
// }
// for(int i=0;i< newarray.size();i++){
// System.out.println(newarray.get(i));
// }
newarray.remove(1);
newarray.add(1, "Lisa");
Boolean containsornot=newarray.contains("Lisa");
for(String i:newarray){
System.out.println(i);
}
System.out.println(containsornot);
System.out.println(newarray.indexOf("john"));
System.out.println(newarray.indexOf("John"));
System.out.println(newarray.isEmpty());
System.out.println(newarray.set(1, "kevin"));
for(String i:newarray){
System.out.println(i);
}
System.out.println(newarray.toString());
}
}
output: Execute this program to view the result
>>>
package Example1;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Scanner;
public class Arraylist {
public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList newarry=new ArrayList();
newarry.add("abc");
newarry.add("def");
newarry.add("xyz");
newarry.add("232");
newarry.add("121");
// Iterator ite=newarry.iterator();
// while(ite.hasNext()){
// System.out.println(ite.next());
// }
// for(int i=0;i< newarry.size();i++){
// System.out.println(newarry.get(i));
// }
// for(String i:newarry){
// System.out.println(i);
// }
//newarry.remove(2);
//newarry.removeAll(newarry);
for(String i:newarry){
System.out.println(i);
}
}
}
output:
package Example1;
import java.util.Arrays;
public class CopyArray {
public static void main(String[] args) {
// TODO Auto-generated method stub
int[] array1=new int[10];
int randomnumber;
for(int i=0;i< array1.length;i++){
randomnumber=(int)(Math.random()*51);
array1[i]=randomnumber;
}
for(int row:array1){
System.out.print(" "+row+" ");
}
//copy array
System.out.println();
int[] copyarray=Arrays.copyOf(array1, 3);
for(int row:copyarray){
System.out.print(" "+row+" ");
}
//copy array in a particular range
System.out.println();
int[] copyarray2=Arrays.copyOfRange(array1, 2, 6);
for(int row:copyarray2){
System.out.print(" "+row+" ");
}
//sort the array
System.out.println();
Arrays.sort(array1);
int exist=Arrays.binarySearch(array1, 50);
System.out.println(exist);
System.out.println(Arrays.toString(array1));
}
}
output :
package Example1;
public class enhanceforloop {
public static void main(String[] args) {
// TODO Auto-generated method stub
int[] singlearray = new int[10];
int k = 0;
while (k <= 15) {
System.out.print("-");
k++;
}
System.out.println();
for (int i = 0; i < singlearray.length; i++) {
singlearray[i] = i;
}
for (int row : singlearray) {
System.out.print(" " + row + " ");
}
System.out.println();
k = 0;
while (k <= 15) {
System.out.print("-");
k++;
}
System.out.println();
char[][] multiarray = new char[10][10];
for (int i = 0; i < multiarray.length; i++) {
for (int j = 0; j < multiarray[i].length; j++) {
multiarray[i][j] = '*';
}
}
for (char[] row : multiarray) {
for (char column : row) {
System.out.print(" " + column + " ");
}
System.out.println();
}
}
}
>>>
package Example1;
import java.lang.reflect.Array;
public class CreateArray {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("single dimension array");
int[] singlearray = new int[10];
for (int i = 0; i < singlearray.length; i++) {
singlearray[i] = i;
System.out.print(" " + singlearray[i] + " ");
}
System.out.println();
int k = 0;
while (k <= 15) {
System.out.print("-");
k++;
}
System.out.println();
System.out.println("multi dimension array");
int[][] multiarray = new int[10][10];
for (int i = 0; i < multiarray.length; i++) {
for (int j = 0; j < multiarray[i].length; j++) {
multiarray[i][j] = i;
System.out.print("|" + multiarray[i][j] + "|");
}
System.out.println();
}
}
}
output :
package Example1;
import java.util.Arrays;
public class GuessTheStar {
private static char design = '*';
private static int xposition = 0;
private static int yposition = 0;
private static char magiccharacter='A';
private static int randomnumber;
char[][] arraycontent = new char[10][10];
public GuessTheStar(char design) {
this.design = design;
xposition=(int)(Math.random()*10);
yposition=(int)(Math.random()*10);
randomnumber=(int)(Math.random()*24);
magiccharacter=(char) (magiccharacter+randomnumber);
for (int i = 0; i < arraycontent.length; i++) {
for (int j = 0; j < arraycontent[i].length; j++) {
if(xposition==i && yposition==j){
System.out.print(arraycontent[i][j]=magiccharacter);
System.out.print("\t");
}else{
System.out.print(arraycontent[i][j]=this.design);
System.out.print("\t");
}
}
System.out.println("");
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
GuessTheStar obj=new GuessTheStar('*');
}
}
>>>
package Example1;
import java.io.IOException;
import java.util.InputMismatchException;
import java.util.Scanner;
public class ExceptionAgain {
static Scanner scanobj=new Scanner(System.in);
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("how old are you");
int age=checktheage();
if(age!=0){
System.out.println(" you are "+age+" old");
}
}
public static int checktheage(){
try{
return scanobj.nextInt();
}
catch(InputMismatchException e){
System.out.println("Do not enter whole number");
return 0;
}
finally{
System.out.println("clean up code");
}
}
}
>>>
package Example1;
import java.util.InputMismatchException;
import java.util.Scanner;
public class ExceptionAgain {
static Scanner scanobj=new Scanner(System.in);
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("how old are you");
int age=checktheage();
if(age!=0){
System.out.println(" you are "+age+" old");
}
}
public static int checktheage(){
try{
return scanobj.nextInt();
}
catch(InputMismatchException e){
System.out.println("Do not enter whole number");
return 0;
}
}
}
- We can add multiple catch block however the most appropriate exception should be mentioned first then the least excepted exception and then general exception.