Little World of Linux

Jquery

2014-08-09T10:58:00.000-07:00

<!DOCTYPE html>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("input").click(function(){
var selected = $('input:radio[name=Status]:checked').val();
alert(selected);
});
});
</script>
</head>
<body>

<input type="radio" name="Status" value="Dark"> Dark
<input type="radio" name="Status" value="Active"> Active
</body>
</html>

Link Test

2014-04-07T00:38:00.000-07:00

package

com.wfis.lendinggrid;

import

java.io.File;

import

java.io.FileNotFoundException;

import

java.net.SocketException;

import

java.util.List;

import

java.util.Scanner;

import

java.util.TreeSet;

import

org.apache.http.conn.HttpHostConnectException;

import

com.gargoylesoftware.htmlunit.BrowserVersion;

import

com.gargoylesoftware.htmlunit.WebClient;

import

com.gargoylesoftware.htmlunit.html.HtmlPage;

import

com.google.common.collect.ListMultimap;

import

com.google.common.collect.ArrayListMultimap;

public

class FlexLinkTest {

public ListMultimap<String, String> readFile(String environment , String fileName) {

ListMultimap<String, String> domainFileMap = ArrayListMultimap.create();

String domain =

null;

String url =

null;

try {

Scanner domainFileScanner =

new Scanner(new File(fileName));

domainFileScanner.useDelimiter(

"\\|");

System.

out.println("==========================");

System.

out.println("Environment : " + environment );

System.

out.println("==========================");

while (domainFileScanner.hasNext()) {

domain = domainFileScanner.next();

url = domainFileScanner.next();

domainFileMap.put(domain, url);

}

domainFileScanner.close();

}

catch(FileNotFoundException nfe) {

nfe.printStackTrace();

}

return domainFileMap;

}

public void testLinks(ListMultimap<String, String> domainFileMap) {

List<String> url =

null;

for (String key : new TreeSet<String>(domainFileMap.keySet())) {

url = domainFileMap.get(key);

System.

out.println(key);

for (String link : url) {

try {

WebClient webClient =

new WebClient(BrowserVersion.getDefault());

webClient.setTimeout(1500);

HtmlPage page = webClient.getPage(link);

System.

out.println( page.getUrl() + " : " + page.getTitleText() );

webClient.closeAllWindows();

}

catch(HttpHostConnectException hhce) {

System.

err.println("Connection to " + link + " refused.");

}

catch(SocketException se) {

System.

err.println("Connection to " + link + " refused.");

}

catch(ClassCastException cce) {

System.

err.println(url);

}

catch (Exception e) {

e.printStackTrace();

}

@SuppressWarnings("all")

public static void main(String[] args) throws FileNotFoundException {

FlexLinkTest tl =

new FlexLinkTest();

ListMultimap<String, String> domainFileMap =

null;

domainFileMap = tl.readFile(

"PROD","./resource/FlexLinks_PROD.txt");

tl.testLinks(domainFileMap);

System.

out.println();

domainFileMap = tl.readFile(

"UAT","./resource/FlexLinks_UAT.txt");

tl.testLinks(domainFileMap);

System.

out.println();

domainFileMap = tl.readFile(

"SIT","./resource/FlexLinks_SIT.txt");

tl.testLinks(domainFileMap);

System.

out.println();

domainFileMap = tl.readFile(

"DEV","./resource/FlexLinks_DEV.txt");

tl.testLinks(domainFileMap);

}

Array1 - Codingbat

2014-03-31T02:08:00.000-07:00

packagetest.codingbat;

public class Array1 {

// return true if first and last element of array is 6

public boolean firstLast6(int[] nums) {

int length = nums.length;

final int number = 6;

if (nums[0] == number || nums[length-1] == number)

return true;

else

return false;

}

// return true if first and last element of array is same

public booleansameFirstLast(int[] nums) {

if (nums.length == 0)

return false;

else if (nums[0] == nums[nums.length-1])

return true;

else

return false;

}

// return an integer array with value pi (3.14)

public int[] makePi() {

int[] pi = new int[]{3,1,4};

return pi;

}

// return true if first or last elements of both arrays are same

public boolean commonEnd(int[] a, int[] b) {

if(a[0] == b[0] || a[a.length-1] == b[b.length-1])

return true;

else

return false;

}

// return sum of the elements

public int sum3(int[] nums) {

int sum = 0;

for (int i = 0; i < nums.length; i++) {

sum = sum + nums[i];

}

return sum;

}

// rotate elements to the left

public int[] rotateLeft3(int[] nums) {

int temp = 0;

temp = nums[0];

for (int i = 0; i < nums.length; i++) {

if(i==nums.length-1) break;

nums[i] = nums[++i];

--i;

}

nums[nums.length-1] = temp;

return nums;

}

// return elements in reverse order

public int[] reverse3(int[] nums) {

int temp = nums[0];

nums[0] = nums[nums.length-1];

nums[nums.length-1] = temp;

return nums;

}

// find largest between first and last element and set all elements to that value

public int[] maxEnd3(int[] nums) {

int largest = 0;

largest = (nums[0] > nums[nums.length-1]) ? nums[0] : nums[nums.length-1];

for(int i = 0; i < nums.length; i++) {

nums[i] = largest;

}

return nums;

}

// return the sum of the first 2 elements in the array.

// If the array length is less than 2, just sum up the elements that exist,

// returning 0 if the array is length 0.

public int sum2(int[] nums) {

if (nums.length == 0 ) return 0;

else if (nums.length == 1) return nums[0];

else return nums[0] + nums[1];

}

// Given 2 int arrays, a and b, each length 3,

// return a new array length 2 containing their middle elements.

public int[] middleWay(int[] a, int[] b) {

int newArray[] = new int[]{a[1],b[1]};

return newArray;

}

// Given an int array, return a new array with double the length where its last element

// is the same as the original array, and all the other elements are 0.

// The original array will be length 1 or more.

public int[] makeLast(int[] nums) {

int length = nums.length;

int newArray[] = new int[2*length];

newArray[newArray.length-1] = nums[nums.length-1];

return newArray;

}

Reducing IF's Using Array

2014-03-20T00:16:00.000-07:00

public class TooMuchIf {

public static voidmain(String[] args) {

TooMuchIf tmi = new TooMuchIf();

System.out.println(tmi.fightMath(3, 3));

System.out.println(tmi.fightMathArray(3, 3));

}

public int fightMath(int one, int two) {

int result = -1;

if(one == 0 && two == 0) { result = 0; }

else if(one == 0 && two == 1) { result = 0; }

else if(one == 0 && two == 2) { result = 1; }

else if(one == 0 && two == 3) { result = 2; }

else if(one == 1 && two == 0) { result = 0; }

else if(one == 1 && two == 1) { result = 0; }

else if(one == 1 && two == 2) { result = 2; }

else if(one == 1 && two == 3) { result = 1; }

else if(one == 2 && two == 0) { result = 2; }

else if(one == 2 && two == 1) { result = 1; }

else if(one == 2 && two == 2) { result = 3; }

else if(one == 2 && two == 3) { result = 3; }

else if(one == 3 && two == 0) { result = 1; }

else if(one == 3 && two == 1) { result = 2; }

else if(one == 3 && two == 2) { result = 3; }

else if(one == 3 && two == 3) { result = 3; }

return result;

}

public intfightMathArray(int one, int two) {

final int[][] result = new int[][] {{ 0, 0, 1, 2 }, { 0, 0, 2, 1 }, { 2, 1, 3, 3 }, { 1, 2, 3, 3 }};

returnresult[one][two];

}

Creating a simple webservice using JAX-WS

2013-06-28T07:36:00.000-07:00

This example creates a simple webservice using JAX-WS

Message.java

package edu.demo.ws;

importjavax.jws.WebMethod;

importjavax.jws.WebService;

@WebService

public class Message {

@WebMethod

public String getMessage(String text) {

return "Message " + text;

}

Main.java

package edu.demo.ws;

importjavax.xml.ws.Endpoint;

public class Main {

public static void main(String[] args) {

Endpoint.publish("http://localhost:8181/message", new Message());

}

Run the Main.java as Java Application and in the browser open the url http://localhost:8181/message?wsdl

<?xml version="1.0" encoding="UTF-8" ?>

- <!--

Published by JAX-WS RI at http://jax-ws.dev.java.net. RI's version is JAX-WS RI 2.1.6 in JDK 6.

-->

- <!--

Generated by JAX-WS RI at http://jax-ws.dev.java.net. RI's version is JAX-WS RI 2.1.6 in JDK 6.

-->

- <definitions xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tns="http://ws.demo.edu/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://schemas.xmlsoap.org/wsdl/" targetNamespace="http://ws.demo.edu/" name="MessageService">

- <types>

- <xsd:schema>

<xsd:import namespace="http://ws.demo.edu/" schemaLocation="http://localhost:8181/message?xsd=1" />

</xsd:schema>

</types>

- <message name="getMessage">

</message>

- <message name="getMessageResponse">

</message>

- <portType name="Message">

- <operation name="getMessage">

</operation>

</portType>

- <binding name="MessagePortBinding" type="tns:Message">

<soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document" />

- <operation name="getMessage">

<soap:operation soapAction="" />

- <input>

<soap:body use="literal" />

</input>

- <output>

<soap:body use="literal" />

</output>

</operation>

</binding>

- <service name="MessageService">

- <port name="MessagePort" binding="tns:MessagePortBinding">

<soap:address location="http://localhost:8181/message" />

</port>

</service>

</definitions>

Use the URL in the above wsdl under SchemaLocation http://localhost:8181/message?xsd=1

<?xml version="1.0" encoding="UTF-8" ?>

- <!--

Published by JAX-WS RI at http://jax-ws.dev.java.net. RI's version is JAX-WS RI 2.1.6 in JDK 6.

-->

- <xs:schema xmlns:tns="http://ws.demo.edu/" xmlns:xs="http://www.w3.org/2001/XMLSchema" version="1.0" targetNamespace="http://ws.demo.edu/">

<xs:element name="getMessage" type="tns:getMessage" />

<xs:element name="getMessageResponse" type="tns:getMessageResponse" />

- <xs:complexType name="getMessage">

- <xs:sequence>

<xs:element name="arg0" type="xs:string" minOccurs="0" />

</xs:sequence>

</xs:complexType>

- <xs:complexType name="getMessageResponse">

- <xs:sequence>

<xs:element name="return" type="xs:string" minOccurs="0" />

</xs:sequence>

</xs:complexType>

</xs:schema>

Use SoapUI or Webservices Explorer in eclipse, post the Wsdl link and you should be able to use your first webservice

Create new file depending on the last modified time

2012-10-24T21:13:00.000-07:00

The following script would automatically create .trg files if a file doesn’t exist. It also checks for the file last modified time. Here I have placed it as 5 minutes. Only if the file has not been modified for last 5 minutes it goes and creates the .trg file. The timing can be extended as needed. This should prevent the script from creating .trg files for the files that are getting processed.

#!/bin/bash

cd /hulanas/smartdoc/inbound

for file in *.xml

# check if .trg file already exists, if yes ignore

if [ -a $file.trg ]

then

echo "$file.trg already exists"

# check if the file has not been modified for more than 5minutes (time can be increased depending on the requirement)

# if yes, go ahead and create the .trg file.

# This is to prevent .trg files from being created for the files that

# might be getting processed.

elif [ `find $file -type f -mmin +5` ]

then

# create the .trg file

touch $file.trg

done

Reading portion of a huge log file

2012-09-07T04:20:00.005-07:00

If you have a several hundred MB log file, how do you quickly find a portion of it you're interested in? Your vi may not be able to open the file, complaining file too large, and/or take too long and use too much memory. Here's what you can do.

Let's say you want Mon Jul 15's data from July's access_log, here's the command

sed -n '/^Mon Jul 15/p; /^Tue Jul 16/q' access_log > /tmp/qq

Without the quit command, sed would scan the file to the end or till you press ^C. Note the undocumented semicolon that allows you to put two sed commands on one line. (By the way, on Solaris creating a file under /tmp may be faster because tmpfs should be memory-based, unless you're short on RAM. But remember to delete big files under /tmp when you're done because they reduce available swap space.)

OutOfMemoryError vs StackOverflowError

2012-04-28T23:11:00.000-07:00

OutOfMemoryError:
Thrown when Java is running out of memory and cannot allocate any more memory in the heap for the object

StackOverflowError:
The stack space lives at the top-end of the address space and the heap lives at the bottom-end of the address space. As stack grows, it grows downwards. As heap grows, it grows upwards. So there is a potential that the two can collide and when that happens, you get a StackOverflowError thrown. Typically happens when you call some methods recursively (that keeps going-and-going).

Command Line Arguments

2012-04-15T20:44:00.000-07:00

packageorg.training.fundementals;

public class Args {

/**

* @param args

public static void main(String[] args) {

System.out.println(args[0]);

System.out.println(args[1]);

System.out.println(args[2]);

System.out.println(args[3]);

}

C:\> java Args This is a simple Java program

Output:

This

simple

Java

Program

Running Multiple Instances of Tomcat on Windows Machine

2012-02-25T20:51:00.003-08:00

To run multiple instances of tomcat the two most important things that you need are CATALINA_HOME and CATALINA_BASE variables set properly.

CATALINA_HOME refers to the base tomcat directory which has all the files required for starting and stopping tomcat. It mainly includes two folders bin and lib.

CATALINA_HOME would be common for all the tomcat instances running on that machine.

CATALINA_BASE would be different for different instances and each instance would refer to its particular CATALINA_BASE directory. This usually includes the following folders inside it, conf, webapps, temp, work & log.

Inside the conf folder, edit the server.xml file to listen to different ports for different instances.

How to have multiple CATALINA_BASE variables ?

Download and copy the tomcat folder to some directory of your choice. I have installed it like this F:\Servers\apache-tomcat-7.0.26

Now create another folder and inside that create a folder name bin. Inside bin create two files namely startup.bat and shutdown.bat

I created a folder name Elephant (which is one of the name of my tomcat instance) under F:\Servers\

Now in the startup.bat put the following lines and edit the path as appropriate.

set CATALINA_BASE=F:\Servers\Elephant
set CATALINA_HOME=F:\Servers\apache-tomcat-7.0.26
F:\Servers\apache-tomcat-7.0.26\bin\startup.bat

In shutdown.bat put the following:

set CATALINA_BASE=F:\Servers\Elephant
set CATALINA_HOME=F:\Servers\apache-tomcat-7.0.26
F:\Servers\apache-tomcat-7.0.26\bin\shutdown.bat

NetBeans v/s Eclipse

2011-12-08T22:42:00.000-08:00

NetBeans is like the long lost love that has aged with grace and dignity, retaining the characteristics that made you love her in the first place, whereas Eclipse is like the aging, overeating trophy wife who thinks she’s still “all that” and lets you know about it, frequently.

NullPointerException

2011-11-26T21:32:00.000-08:00

packageorg.training.exceptions;

public class NullPointer {

public static void main(String[] args) {

new NullPointer();

}

public NullPointer(){

Object[] object = {12,25,68,45};

try {

for (Object o : object ) {

System.out.println(o);

}

// explicitly dereferencing object array

object = null;

for (Object o : object ) {

System.out.println(o);

}

}catch(NullPointerException nfe) {

nfe.printStackTrace();

}

Output:

java.lang.NullPointerException

at org.training.exceptions.NullPointer.<init>(NullPointer.java:21)

at org.training.exceptions.NullPointer.main(NullPointer.java:7)

ClassNotFoundException

2011-11-26T19:25:00.000-08:00

ClassNotFoundException is one of the most commonly occurring exceptions. This exception is thrown when the executing program is unable to find the defined class. This could be because of various reasons, wrong classpath, older version of jar file etc...

packageorg.training.exceptions;

public class ClassNotFound {

public static void main(String[] args) {

new ClassNotFound();

}

publicClassNotFound(){

try {

// load the java.lang.Strung class,

// this would thrown an ClassNotFoundException

because there is no class called “Strung” defined in the java.lang package

Class c = Class.forName("java.lang.Strung");

}catch(ClassNotFoundException cnfe) {

cnfe.printStackTrace();

}

Output:

java.lang.ClassNotFoundException: java.lang.Strung

at java.net.URLClassLoader$1.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Unknown Source)

at org.training.exceptions.ClassNotFound.<init>(ClassNotFound.java:14)

at org.training.exceptions.ClassNotFound.main(ClassNotFound.java:7)

NoSuchMethodException

2011-11-26T19:11:00.000-08:00

packageorg.training.exceptions;

importjava.lang.reflect.Method;

public class NoSuchMethod {

public static void main(String[] args) {

new NoSuchMethod();

}

public NoSuchMethod(){

try {
// load the java.lang.String class, if not found throws ClassNotFoundException

Class c = Class.forName("java.lang.String");

try {

Class[] arguments = new Class[2];

// search for method called "someMethod" with two parameters

// since there is no method called "someMethod(arg1, arg2)", in the java.lang.String class, this throws an NoSuchMethodException

Method m = c.getDeclaredMethod("someMethod", arguments);

}catch(NoSuchMethodException nsme) {

nsme.printStackTrace();

}

}catch(ClassNotFoundException cnfe) {

cnfe.printStackTrace();

}

Output:

java.lang.NoSuchMethodException: java.lang.String.someMethod(null, null)

at java.lang.Class.getDeclaredMethod(Unknown Source)

at org.training.exceptions.NoSuchMethod.<init>(NoSuchMethod.java:19)

at org.training.exceptions.NoSuchMethod.main(NoSuchMethod.java:9)

NumberFormatException

2011-11-25T03:57:00.000-08:00

packageorg.training.exceptions;

public class NumberFormat {

public static void main(String[] args) {

String string = "hello";

try {

// this parsing doesn't work as hello is not a number

Integer integer = Integer.parseInt(string);

System.out.println(integer++);

}catch(NumberFormatException nfe) {

System.out.println("Number Format Exception caught, check what you are parsing");

nfe.printStackTrace();

}

Output:

Number Format Exception caught, check what you are parsing

java.lang.NumberFormatException: For input string: "hello"

at java.lang.NumberFormatException.forInputString(Unknown Source)

at java.lang.Integer.parseInt(Unknown Source)

at org.training.exceptions.NumberFormat.main(NumberFormat.java:11)

NegativeArraySizeException

2011-11-25T01:00:00.000-08:00

packageorg.training.exceptions;

public classNegativeArraySize {

public static void main(String[] args) {

int array[] = {1,2,3,4,5};

try {

array = new int[-8];

}catch(NegativeArraySizeException nase) {

System.err.println("Negative Array Size Exception has occured, check array initialization again. ");

}

for (int i: array) {

System.out.println(i);

}

Output:

Negative Array Size Exception has occurred, check array initialization again.

IndexOutOfBoundsException

2011-11-25T00:46:00.000-08:00

packageorg.training.exceptions;

public classIndexOutOfBounds {

public static void main(String[] args) {

String s = "abc";

for (int i = 0 ; i < 4 ; i++) {

try {

System.out.println(s.charAt(i));

}catch(IndexOutOfBoundsException iobe){

System.err.println("Index Out Of Bounds Exception has occured");

}

Output:

Index Out Of Bounds Exception has occured

IllegalArgumentException

2011-11-24T22:54:00.000-08:00

packageorg.training.exceptions;

public class IllegalArgument {

public static void main(String[] args) {

IllegalArgument ia = new IllegalArgument();

try {

ia.simpleMethod("Hello");

ia.simpleMethod(null);

}catch(IllegalArgumentException iae) {

System.err.println("Illegal Argument Exception has been caught, check your arguments again");

iae.printStackTrace();

}

public voidsimpleMethod(String argument) {

if(argument == null) {

throw newIllegalArgumentException();

}else

System.out.println(argument);

}

Output:

Hello

Illegal Argument Exception has been caught, check your arguments again

java.lang.IllegalArgumentException

at org.training.exceptions.IllegalArgument.simpleMethod(IllegalArgument.java:19)

at org.training.exceptions.IllegalArgument.main(IllegalArgument.java:10)

ClassCastException

2011-11-24T21:20:00.000-08:00

A class cast exception is thrown by Java when you try to cast an Object of one data type to another.

Java allows us to cast variables of one type to another as long as the casting happens between compatible data types.

For example you can cast a String as an Object and similarly an Object that contains String values can be cast to a String.

package com.training.exceptions;

class Vehicle {

public void doStuff() {

System.out.println("Vehicle");

}

class Car extends Vehicle{

public void doStuff() {

System.out.println("Car");

}

class Bike extends Vehicle {

public void doStuff() {

System.out.println("bike");

}

public class ClassCast {

public static void main(String[] args) {

try {

// this will throw a ClassCastException

Vehicle v = (Bike)new Vehicle();

v.doStuff();

}catch(ClassCastException cce) {

System.err.println("Class Cast Exception has been caught, check your code again");

cce.printStackTrace();

}

Output:

Class Cast Exception has been caught, check your code again

java.lang.ClassCastException: com.training.inheritance.Vehicle

at com.training.inheritance.VehicleTest.main(VehicleTest.java:30)

ArrayIndexOutOfBoundsException

2011-11-24T20:40:00.000-08:00

packageorg.training.exceptions;

public classArrayIndexOutOfBounds {

public static void main(String[] args) {

int array[] = new int[3];

for (int i = 0; i < 4; /* this condition checks for more space that allocated for the array */ i++) {

try {

array[i] = i;

}catch(ArrayIndexOutOfBoundsException aiobe) {

System.err.println("Array Index Out Of Bounds Exception has been caught, check your code again");

aiobe.printStackTrace();

}

for ( int x : array) {

System.out.println(x);

}

Output:

Array Index Out Of Bounds Exception has been caught, check your code again

java.lang.ArrayIndexOutOfBoundsException: 3

at org.training.exceptions.ArrayIndexOutOfBounds.main(ArrayIndexOutOfBounds.java:12)

ArithmeticException

2011-11-24T20:08:00.000-08:00

ArithmeticException is to catch arithmetic errors, like divide by zero. Following is the code that demonstrates this.

packageorg.training.exceptions;

public class Arithmetic {

public static void main(String[] args) {

int x = 0;

int y = 10;

int z = 0;

try {

// this is prone for arithmetic exception,

z = y / x;

}catch(ArithmeticException ae) {

System.err.println("Arithmetic Exception has been caught, check your code again.");

ae.printStackTrace();

}

Output:

Arithmetic Exception has been caught, check your code again.

java.lang.ArithmeticException: / by zero

at org.training.exceptions.Arithmetic.main(Arithmetic.java:13)

ArrayStoreException

2011-11-24T19:57:00.000-08:00

ArrayStoreException is caused when we try to assign an array element of incompatible type. Following is the program that demonstrates it.

packageorg.training.exceptions;

public class ArrayStore {

public static void main(String[] args) {

Object array[] = new String[1];

for(int i = 0; i < array.length; i++) {

try {

// assigning an integer where String is expected

array[i] = new Integer(i);

}catch(ArrayStoreException ase) {

System.err.println("Array Store Exception has been caught, check whether you are passing incompatiable types to your array.");

System.err.println("Stack Trace: ");

ase.printStackTrace();

}

for (Object o : array) {

System.out.println(o);

}

Output:

null

Array Store Exception has been caught, check whether you are passing incompatiable types to your array.

Stack Trace:

java.lang.ArrayStoreException: java.lang.Integer

at org.training.exceptions.ArrayStore.main(ArrayStore.java:12)

Executing a Java class without main

2011-11-15T19:26:00.000-08:00

Is it possible to execute a java class without main function without throwing exceptions?

The following program does J

packageorg.training.simple;

public class WithoutMain {

static {

System.out.println("This executes without main");

System.exit(0);

}

Output:

This executes without main

Number of classes loaded for a simple java program

2011-11-15T18:50:00.000-08:00

Ever wondered how many classes are loaded into memory by the JVM for a simple hello world program execution. Java being a dynamically loaded language even if we import an entire package using the .* option, only the classes that are needed during the runtime are loaded. When I first encountered this question all I could think of was 3 classes. The String, System and the out classes. But when I worked towards it only then I found that there are around 310 classes loaded using JRE 1.6 for this simple program. I had missed many things. The main thing I missed was the inheritance concept. Every class in Java extends the Object class so that needs to be loaded. Every Java program is a thread by itself so thread class is loaded, exception class is loaded for catching any exceptions. In such way all in all 310 classes are loaded for execution of this program J

packageorg.training.simple;

public class HelloWorld {

public static void main(String[] args) {

System.out.println("Hello World");

}

To check the classes that are loaded during the execution of program in command line type

C:\> java –verbose:class classname

Incase you are using eclipse, right click on the class you want to execute, go to Run as > Run Configurations > click the arguments tab and under VM arguments type in –verbose:class click on apply and run.

The following classes are loaded

[Loaded java.lang.Object from shared objects file]

[Loaded java.io.Serializable from shared objects file]

[Loaded java.lang.Comparable from shared objects file]

[Loaded java.lang.CharSequence from shared objects file]

[Loaded java.lang.String from shared objects file]

[Loaded java.lang.reflect.GenericDeclaration from shared objects file]

[Loaded java.lang.reflect.Type from shared objects file]

[Loaded java.lang.reflect.AnnotatedElement from shared objects file]

[Loaded java.lang.Class from shared objects file]

[Loaded java.lang.Cloneable from shared objects file]

[Loaded java.lang.ClassLoader from shared objects file]

[Loaded java.lang.System from shared objects file]

[Loaded java.lang.Throwable from shared objects file]

[Loaded java.lang.Error from shared objects file]

[Loaded java.lang.ThreadDeath from shared objects file]

[Loaded java.lang.Exception from shared objects file]

[Loaded java.lang.RuntimeException from shared objects file]

[Loaded java.security.ProtectionDomain from shared objects file]

[Loaded java.security.AccessControlContext from shared objects file]

[Loaded java.lang.ClassNotFoundException from shared objects file]

[Loaded java.lang.LinkageError from shared objects file]

[Loaded java.lang.NoClassDefFoundError from shared objects file]

[Loaded java.lang.ClassCastException from shared objects file]

[Loaded java.lang.ArrayStoreException from shared objects file]

[Loaded java.lang.VirtualMachineError from shared objects file]

[Loaded java.lang.OutOfMemoryError from shared objects file]

[Loaded java.lang.StackOverflowError from shared objects file]

[Loaded java.lang.IllegalMonitorStateException from shared objects file]

[Loaded java.lang.ref.Reference from shared objects file]

[Loaded java.lang.ref.SoftReference from shared objects file]

[Loaded java.lang.ref.WeakReference from shared objects file]

[Loaded java.lang.ref.FinalReference from shared objects file]

[Loaded java.lang.ref.PhantomReference from shared objects file]

[Loaded java.lang.ref.Finalizer from shared objects file]

[Loaded java.lang.Runnable from shared objects file]

[Loaded java.lang.Thread from shared objects file]

[Loaded java.lang.Thread$UncaughtExceptionHandler from shared objects file]

[Loaded java.lang.ThreadGroup from shared objects file]

[Loaded java.util.Dictionary from shared objects file]

[Loaded java.util.Map from shared objects file]

[Loaded java.util.Hashtable from shared objects file]

[Loaded java.util.Properties from shared objects file]

[Loaded java.lang.reflect.AccessibleObject from shared objects file]

[Loaded java.lang.reflect.Member from shared objects file]

[Loaded java.lang.reflect.Field from shared objects file]

[Loaded java.lang.reflect.Method from shared objects file]

[Loaded java.lang.reflect.Constructor from shared objects file]

[Loaded sun.reflect.MagicAccessorImpl from shared objects file]

[Loaded sun.reflect.MethodAccessor from shared objects file]

[Loaded sun.reflect.MethodAccessorImpl from shared objects file]

[Loaded sun.reflect.ConstructorAccessor from shared objects file]

[Loaded sun.reflect.ConstructorAccessorImpl from shared objects file]

[Loaded sun.reflect.DelegatingClassLoader from shared objects file]

[Loaded sun.reflect.ConstantPool from shared objects file]

[Loaded sun.reflect.FieldAccessor from shared objects file]

[Loaded sun.reflect.FieldAccessorImpl from shared objects file]

[Loaded sun.reflect.UnsafeFieldAccessorImpl from shared objects file]

[Loaded sun.reflect.UnsafeStaticFieldAccessorImpl from shared objects file]

[Loaded java.lang.Appendable from shared objects file]

[Loaded java.lang.AbstractStringBuilder from shared objects file]

[Loaded java.lang.StringBuffer from shared objects file]

[Loaded java.lang.StringBuilder from shared objects file]

[Loaded java.lang.StackTraceElement from shared objects file]

[Loaded java.nio.Buffer from shared objects file]

[Loaded sun.misc.AtomicLong from shared objects file]

[Loaded sun.misc.AtomicLongCSImpl from shared objects file]

[Loaded sun.misc.PostVMInitHook from shared objects file]

[Loaded java.lang.Boolean from shared objects file]

[Loaded java.lang.Character from shared objects file]

[Loaded java.lang.Number from shared objects file]

[Loaded java.lang.Float from shared objects file]

[Loaded java.lang.Double from shared objects file]

[Loaded java.lang.Byte from shared objects file]

[Loaded java.lang.Short from shared objects file]

[Loaded java.lang.Integer from shared objects file]

[Loaded java.lang.Long from shared objects file]

[Loaded java.io.ObjectStreamField from shared objects file]

[Loaded java.util.Comparator from shared objects file]

[Loaded java.lang.String$CaseInsensitiveComparator from shared objects file]

[Loaded java.security.Guard from shared objects file]

[Loaded java.security.Permission from shared objects file]

[Loaded java.security.BasicPermission from shared objects file]

[Loaded java.lang.RuntimePermission from shared objects file]

[Loaded java.util.AbstractMap from shared objects file]

[Loaded sun.misc.SoftCache from shared objects file]

[Loaded java.lang.ref.ReferenceQueue from shared objects file]

[Loaded java.lang.ref.ReferenceQueue$Null from shared objects file]

[Loaded java.lang.ref.ReferenceQueue$Lock from shared objects file]

[Loaded java.util.HashMap from shared objects file]

[Loaded java.util.Map$Entry from shared objects file]

[Loaded java.util.HashMap$Entry from shared objects file]

[Loaded java.security.AccessController from shared objects file]

[Opened C:\Program Files\Java\jre6\lib\rt.jar]

[Loaded sun.misc.JavaSecurityAccess from C:\Program Files\Java\jre6\lib\rt.jar]

[Loaded java.security.AccessControlContext$1 from C:\Program Files\Java\jre6\lib\rt.jar]

[Loaded sun.misc.SharedSecrets from shared objects file]

[Loaded sun.misc.Unsafe from shared objects file]

[Loaded java.lang.IncompatibleClassChangeError from shared objects file]

[Loaded java.lang.NoSuchMethodError from shared objects file]

[Loaded sun.reflect.Reflection from shared objects file]

[Loaded java.util.Collections from shared objects file]

[Loaded java.lang.Iterable from shared objects file]

[Loaded java.util.Collection from shared objects file]

[Loaded java.util.AbstractCollection from shared objects file]

[Loaded java.util.Set from shared objects file]

[Loaded java.util.AbstractSet from shared objects file]

[Loaded java.util.Collections$EmptySet from shared objects file]

[Loaded java.util.List from shared objects file]

[Loaded java.util.AbstractList from shared objects file]

[Loaded java.util.RandomAccess from shared objects file]

[Loaded java.util.Collections$EmptyList from shared objects file]

[Loaded java.util.Collections$EmptyMap from shared objects file]

[Loaded java.util.Collections$ReverseComparator from shared objects file]

[Loaded java.util.Collections$SynchronizedMap from shared objects file]

[Loaded java.lang.reflect.ReflectPermission from shared objects file]

[Loaded java.security.PrivilegedAction from shared objects file]

[Loaded sun.reflect.ReflectionFactory$GetReflectionFactoryAction from shared objects file]

[Loaded java.util.Vector from shared objects file]

[Loaded java.util.Stack from shared objects file]

[Loaded sun.reflect.ReflectionFactory from shared objects file]

[Loaded java.lang.ref.Reference$Lock from shared objects file]

[Loaded java.lang.ref.Reference$ReferenceHandler from shared objects file]

[Loaded java.lang.ref.Finalizer$FinalizerThread from shared objects file]

[Loaded java.util.Enumeration from shared objects file]

[Loaded java.util.Hashtable$EmptyEnumerator from shared objects file]

[Loaded java.util.Iterator from shared objects file]

[Loaded java.util.Hashtable$EmptyIterator from shared objects file]

[Loaded java.util.Hashtable$Entry from shared objects file]

[Loaded sun.misc.Version from shared objects file]

[Loaded sun.misc.JavaLangAccess from shared objects file]

[Loaded java.lang.System$2 from shared objects file]

[Loaded sun.misc.VM from shared objects file]

[Loaded java.lang.Runtime from shared objects file]

[Loaded java.io.File from shared objects file]

[Loaded java.io.FileSystem from shared objects file]

[Loaded java.io.Win32FileSystem from shared objects file]

[Loaded java.io.WinNTFileSystem from shared objects file]

[Loaded java.io.ExpiringCache from shared objects file]

[Loaded java.util.LinkedHashMap from shared objects file]

[Loaded java.io.ExpiringCache$1 from shared objects file]

[Loaded java.util.LinkedHashMap$Entry from shared objects file]

[Loaded sun.security.action.GetPropertyAction from shared objects file]

[Loaded java.util.Arrays from shared objects file]

[Loaded java.lang.Math from shared objects file]

[Loaded sun.jkernel.DownloadManager from shared objects file]

[Loaded java.lang.ThreadLocal from shared objects file]

[Loaded sun.jkernel.DownloadManager$1 from shared objects file]

[Loaded java.util.concurrent.atomic.AtomicInteger from shared objects file]

[Loaded java.lang.Class$3 from shared objects file]

[Loaded java.lang.reflect.Modifier from shared objects file]

[Loaded sun.reflect.LangReflectAccess from shared objects file]

[Loaded java.lang.reflect.ReflectAccess from shared objects file]

[Loaded sun.jkernel.DownloadManager$2 from shared objects file]

[Loaded java.lang.StringValue from shared objects file]

[Loaded java.lang.ClassLoader$3 from shared objects file]

[Loaded java.io.ExpiringCache$Entry from shared objects file]

[Loaded java.lang.ClassLoader$NativeLibrary from shared objects file]

[Loaded java.io.Closeable from shared objects file]

[Loaded java.io.InputStream from shared objects file]

[Loaded java.io.FileInputStream from shared objects file]

[Loaded java.io.FileDescriptor from shared objects file]

[Loaded java.io.Flushable from shared objects file]

[Loaded java.io.OutputStream from shared objects file]

[Loaded java.io.FileOutputStream from shared objects file]

[Loaded java.io.FilterInputStream from shared objects file]

[Loaded java.io.BufferedInputStream from shared objects file]

[Loaded java.util.concurrent.atomic.AtomicReferenceFieldUpdater from shared objects file]

[Loaded java.util.concurrent.atomic.AtomicReferenceFieldUpdater$AtomicReferenceFieldUpdaterImpl from shared objects file]

[Loaded sun.reflect.misc.ReflectUtil from shared objects file]

[Loaded java.io.FilterOutputStream from shared objects file]

[Loaded java.io.PrintStream from shared objects file]

[Loaded java.io.BufferedOutputStream from shared objects file]

[Loaded java.io.Writer from shared objects file]

[Loaded java.io.OutputStreamWriter from shared objects file]

[Loaded sun.nio.cs.StreamEncoder from shared objects file]

[Loaded java.nio.charset.Charset from shared objects file]

[Loaded java.nio.charset.spi.CharsetProvider from shared objects file]

[Loaded sun.nio.cs.FastCharsetProvider from shared objects file]

[Loaded sun.nio.cs.StandardCharsets from shared objects file]

[Loaded sun.util.PreHashedMap from shared objects file]

[Loaded sun.nio.cs.StandardCharsets$Aliases from shared objects file]

[Loaded sun.nio.cs.StandardCharsets$Classes from shared objects file]

[Loaded sun.nio.cs.StandardCharsets$Cache from shared objects file]

[Loaded sun.nio.cs.HistoricallyNamedCharset from shared objects file]

[Loaded sun.nio.cs.MS1252 from shared objects file]

[Loaded java.lang.Class$1 from shared objects file]

[Loaded sun.reflect.ReflectionFactory$1 from shared objects file]

[Loaded sun.reflect.NativeConstructorAccessorImpl from shared objects file]

[Loaded sun.reflect.DelegatingConstructorAccessorImpl from shared objects file]

[Loaded java.nio.charset.CharsetEncoder from shared objects file]

[Loaded sun.nio.cs.SingleByteEncoder from shared objects file]

[Loaded sun.nio.cs.MS1252$Encoder from shared objects file]

[Loaded java.nio.charset.CodingErrorAction from shared objects file]

[Loaded java.nio.charset.CharsetDecoder from shared objects file]

[Loaded sun.nio.cs.SingleByteDecoder from shared objects file]

[Loaded sun.nio.cs.MS1252$Decoder from shared objects file]

[Loaded java.nio.ByteBuffer from shared objects file]

[Loaded java.nio.HeapByteBuffer from shared objects file]

[Loaded java.nio.Bits from shared objects file]

[Loaded java.nio.ByteOrder from shared objects file]

[Loaded java.lang.Readable from shared objects file]

[Loaded java.nio.CharBuffer from shared objects file]

[Loaded java.nio.HeapCharBuffer from shared objects file]

[Loaded java.nio.charset.CoderResult from shared objects file]

[Loaded java.nio.charset.CoderResult$Cache from shared objects file]

[Loaded java.nio.charset.CoderResult$1 from shared objects file]

[Loaded java.nio.charset.CoderResult$2 from shared objects file]

[Loaded sun.nio.cs.Surrogate$Parser from shared objects file]

[Loaded sun.nio.cs.Surrogate from shared objects file]

[Loaded java.io.BufferedWriter from shared objects file]

[Loaded java.lang.Terminator from shared objects file]

[Loaded sun.misc.SignalHandler from shared objects file]

[Loaded java.lang.Terminator$1 from shared objects file]

[Loaded sun.misc.Signal from shared objects file]

[Loaded sun.misc.NativeSignalHandler from shared objects file]

[Loaded sun.misc.OSEnvironment from shared objects file]

[Loaded sun.io.Win32ErrorMode from shared objects file]

[Loaded java.lang.NullPointerException from shared objects file]

[Loaded java.lang.ArithmeticException from shared objects file]

[Loaded java.lang.Compiler from shared objects file]

[Loaded java.lang.Compiler$1 from shared objects file]

[Loaded sun.misc.Launcher from shared objects file]

[Loaded java.net.URLStreamHandlerFactory from shared objects file]

[Loaded sun.misc.Launcher$Factory from shared objects file]

[Loaded java.security.SecureClassLoader from shared objects file]

[Loaded java.net.URLClassLoader from shared objects file]

[Loaded sun.misc.Launcher$ExtClassLoader from shared objects file]

[Loaded sun.security.util.Debug from shared objects file]

[Loaded java.lang.Package from shared objects file]

[Loaded java.net.URL from shared objects file]

[Loaded java.security.CodeSource from shared objects file]

[Loaded java.lang.Void from shared objects file]

[Loaded java.security.cert.Certificate from shared objects file]

[Loaded java.lang.ClassFormatError from shared objects file]

[Loaded java.lang.IllegalArgumentException from shared objects file]

[Loaded java.io.IOException from shared objects file]

[Loaded sun.misc.URLClassPath from shared objects file]

[Loaded java.lang.AssertionStatusDirectives from shared objects file]

[Loaded sun.misc.JavaNetAccess from shared objects file]

[Loaded java.net.URLClassLoader$7 from shared objects file]

[Loaded java.security.PermissionCollection from shared objects file]

[Loaded java.util.StringTokenizer from shared objects file]

[Loaded java.security.PrivilegedExceptionAction from shared objects file]

[Loaded sun.misc.Launcher$ExtClassLoader$1 from shared objects file]

[Loaded sun.misc.MetaIndex from shared objects file]

[Loaded java.io.Reader from shared objects file]

[Loaded java.io.BufferedReader from shared objects file]

[Loaded java.io.InputStreamReader from shared objects file]

[Loaded java.io.FileReader from shared objects file]

[Loaded sun.nio.cs.StreamDecoder from shared objects file]

[Loaded java.util.ArrayList from shared objects file]

[Loaded java.lang.reflect.Array from shared objects file]

[Loaded java.util.Locale from shared objects file]

[Loaded java.util.concurrent.ConcurrentMap from shared objects file]

[Loaded java.util.concurrent.ConcurrentHashMap from shared objects file]

[Loaded java.util.concurrent.locks.Lock from shared objects file]

[Loaded java.util.concurrent.locks.ReentrantLock from shared objects file]

[Loaded java.util.concurrent.ConcurrentHashMap$Segment from shared objects file]

[Loaded java.util.concurrent.locks.AbstractOwnableSynchronizer from shared objects file]

[Loaded java.util.concurrent.locks.AbstractQueuedSynchronizer from shared objects file]

[Loaded java.util.concurrent.locks.ReentrantLock$Sync from shared objects file]

[Loaded java.util.concurrent.locks.ReentrantLock$NonfairSync from shared objects file]

[Loaded java.util.concurrent.locks.AbstractQueuedSynchronizer$Node from shared objects file]

[Loaded java.util.concurrent.ConcurrentHashMap$HashEntry from shared objects file]

[Loaded java.lang.CharacterDataLatin1 from shared objects file]

[Loaded java.io.ObjectStreamClass from shared objects file]

[Loaded sun.net.www.ParseUtil from shared objects file]

[Loaded java.util.BitSet from shared objects file]

[Loaded java.net.Parts from shared objects file]

[Loaded java.net.URLStreamHandler from shared objects file]

[Loaded sun.net.www.protocol.file.Handler from shared objects file]

[Loaded java.util.HashSet from shared objects file]

[Loaded sun.net.www.protocol.jar.Handler from shared objects file]

[Loaded sun.misc.Launcher$AppClassLoader from shared objects file]

[Loaded sun.misc.Launcher$AppClassLoader$1 from shared objects file]

[Loaded java.lang.SystemClassLoaderAction from shared objects file]

[Loaded java.lang.StringCoding from shared objects file]

[Loaded java.lang.ThreadLocal$ThreadLocalMap from shared objects file]

[Loaded java.lang.ThreadLocal$ThreadLocalMap$Entry from shared objects file]

[Loaded java.lang.StringCoding$StringDecoder from shared objects file]

[Loaded java.net.URLClassLoader$1 from shared objects file]

[Loaded sun.net.util.URLUtil from shared objects file]

[Loaded sun.misc.URLClassPath$3 from shared objects file]

[Loaded sun.misc.URLClassPath$Loader from shared objects file]

[Loaded sun.misc.URLClassPath$JarLoader from shared objects file]

[Loaded java.security.PrivilegedActionException from shared objects file]

[Loaded sun.misc.URLClassPath$FileLoader from shared objects file]

[Loaded sun.misc.Resource from shared objects file]

[Loaded sun.misc.URLClassPath$FileLoader$1 from shared objects file]

[Loaded sun.nio.ByteBuffered from shared objects file]

[Loaded java.security.Permissions from shared objects file]

[Loaded java.net.URLConnection from shared objects file]

[Loaded sun.net.www.URLConnection from shared objects file]

[Loaded sun.net.www.protocol.file.FileURLConnection from shared objects file]

[Loaded java.net.ContentHandler from shared objects file]

[Loaded java.net.UnknownContentHandler from shared objects file]

[Loaded sun.net.www.MessageHeader from shared objects file]

[Loaded java.io.FilePermission from shared objects file]

[Loaded java.io.FilePermission$1 from shared objects file]

[Loaded java.security.Policy from shared objects file]

[Loaded sun.security.provider.PolicyFile from shared objects file]

[Loaded java.security.Policy$UnsupportedEmptyCollection from shared objects file]

[Loaded java.io.FilePermissionCollection from shared objects file]

[Loaded java.security.AllPermission from shared objects file]

[Loaded java.security.UnresolvedPermission from shared objects file]

[Loaded java.security.BasicPermissionCollection from shared objects file]

[Loaded sun.misc.JavaSecurityProtectionDomainAccess from C:\Program Files\Java\jre6\lib\rt.jar]

[Loaded java.security.ProtectionDomain$2 from C:\Program Files\Java\jre6\lib\rt.jar]

[Loaded java.security.ProtectionDomain$Key from C:\Program Files\Java\jre6\lib\rt.jar]

[Loaded java.security.Principal from shared objects file]

[Loaded org.training.simple.HelloWorld from file:/H:/Personal%20Project/JavaTraining/SetProject/bin/]

Hello World

[Loaded java.lang.Shutdown from shared objects file]

[Loaded java.lang.Shutdown$Lock from shared objects file]

Constructor based Dependency Injection

2011-11-07T02:29:00.000-08:00

// Constructor based dependency Injection

public class ConstructorInjection {

private Dependency dep;

publicConstructorInjection(Dependency dep){

this.dep = dep;

}