Java Tech Knowledge: October 2013

How to install Ant on Windows System

How to install Ant on windows System

1. Download ANT http://ant.apache.org/
2. Unzip it and rename it to ant
3. Set environmental variables JAVA_HOME to your Java environment, ANT_HOME to the directory you uncompressed, to do it on command prompt type this (Assume Ant is installed in E:\ant\.)

set ANT_HOME=E:\ant
set JAVA_HOME=D:\Program Files\Java\jdk1.6.0_03
set PATH=%PATH%;%ANT_HOME%\bin

In windows 7 you can go to Control Panel\All Control Panel Items\System or right click on Computer and then to “Advance system setting”

-Choose Advanced Tab
-Press Environtmen Variables Button
-In the System Variables, click New Button

Give the Variable Name:ANT_HOME
Give the Value: E:\ant
Click OK

Then,we’ll add new ANT_HOME path,
And Click again on New Button if you do not have ‘path’ Variable in there, if so select it and edit as

Give the Variable Name:path
Give the Value D:\Program Files\Java\jdk1.6.0_03\bin;%ANT_HOME%\bin
Click OK

4. Check wheter ANT works correctly or not.
In the command prompt, type:
ant -version

I got Apache Ant version 1.9.2 compiled on October 17 2013
You may be get different version based on the version you have downloaded from the apache. In my case it will be 1.9.2 .

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How To Set Up Master Slave Replication in MySQL

How To Set Up Master Slave Replication in MySQL

1. Create new user for the purpose of replication which will be used by client to connect master.

mysql > CREATE USER 'repl'@'%.mydomain.com' IDENTIFIED BY 'slavepass';

Grant replication privileges to newly created user

mysql > GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%.mydomain.com';

2. Configure Master Server. On master server open my.ini file available in MySql program files folder.
Add following variables to that file. (For this you may need administrator privileges)

Variable name	Value	Comment
tmpdir	Temp folder path	Value should be placed in double quotes
server_id	1	Value should be unique among the master and client db server.
log-bin	Log file path	File should have extension “.log”. Place in double quotes
log-error	Error log file path	File should have extension “.log”. Place in double quotes
log-bin-index	Index file path	File should have extension “.index”. Place in double quotes

3. Configure Slave (client) server.On client server open my.ini file available in Mysql program files folder.

Add following variables to that file. (For this you may need administrator privileges)

Variable name	Value	Comment
server_id	2	Value should be unique among the master and client db server.
master-host	IP address of master db sever
master-port	Port no of master db server.
master-user	Username of master db server
master-password	Password of master db server
log-bin	Log file path	Same as in master.
log-bin-index	Index file path	Same as in master.
log-error	Error log file path	Same as in master.
relay-log	Relay log file path	Same as in master.
relay-log-info-file	Info file path	Same as in master.
relay-log-index	Index file path	Same as in master.

4. Export / Import existing MySql database.

This step is not required if you are setting up replication master-client for new database.

Restart master and client server services respectively.

Create a database dump from master server of your choice database.

On client MySql server, enter command

mysql > STOP SLAVE

Restore same dump in the client server where you want to replicate existing database.

Note: For the above process, stop all the writable queries on the master server so that no further updates are possible. This is to ensure that both client and master have same database with same table structure and with same data.

If database is particularly very large then just create a zip file of the database you want from data folder in MySql server and place it in same data folder of client server and unzip it.

5. Start Replication

On the master database server restart the MySQL service.
On the slave database server restart the MySQL service.
On the client MySQL server, enter command :
mysql > START SLAVE
On the slave database server issue the following command from the MySQL command line client or regular command Window :

You should get :
Slave_IO_Running : Yes
Slave_SQL_Running : Yes

If this is the result in above window, your replication is succsessfull. Enjoy it..

posted under MySQL | 2 Comments

How to resize an array in java

In General terms, As we know that we cannot resize an array once we initialized because array defination says that an array is an fixed size,sequence and collection of similar data type. But It is possible to resize an array, resizing an array is nothing but copy the content of old array to new index array as per our requirement. Following code snippets is usefull for resize an array. Java.lang.System.arraycopy() Method is responsible for resizing an array.

File Name : ResizeArray.java

What is Java.lang.System.arraycopy() Method :
The java.lang.System.arraycopy() method copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array. A subsequence of array components are copied from the source array referenced by src to the destination array referenced by dest.The number of components copied is equal to the length argument.
The components at positions srcPos through srcPos + length - 1 in the source array are copied into positions destPos through destPos + length - 1, respectively, of the destination array.
Syntax :

Parameters:

src -- This is the source array.
srcPos -- This is the starting position in the source array.
dest -- This is the destination array.
destPos -- This is the starting position in the destination data.
length -- This is the number of array elements to be copied.

Return Value: Method does not return any value.
Exception Details:

IndexOutOfBoundsException --if copying would cause access of data outside array bounds.
ArrayStoreException -- if an element in the src array could not be stored into the dest array because of a type mismatch.
NullPointerException -- if either src or dest is null.

Another Example : File Name :TestSystemDemo.java

output : array2 = 0 10 20 30 40

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How to read XML file in java

How To Read/Parse XML File In Java

Here you will find the program which read/parse xml file. It will provide you a basic guide to parse your XML document, Your codding may be different as per your requirement. Here you will find mathod called getAllStudentNames(String fileName). Please provide fileName as full path of your XML file source.

File Name : XMLParser.java

File Name : student.xml

posted under Java | 1 Comments

How to take screen shots in Java

Following piece of code in Java that takes the screen shot of your desktop and save it in a PNG file. This example uses java.awt.Robot class to capture the screen pixels and returns a BufferedImage. Java.awt.Robot class is used to take the control of mouse and keyboard. Once you get the control, you can do any type of operation related to mouse and keyboard through your java code. This class is used generally for test automation. Copy and paste following code in your Java class and invoke the method captureScreen() with file name as argument. The screen shot will be stored in the file that you specified in argument. Please enter the full file path.

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Manipulate ISO Dates in Javascript

Following code helps you to find total number of weeks in javascript as well as getISOYear, getISOWeek.

Manipulate ISO Dates in Javascript

posted under Date, Javascript | 0 Comments

Date Manipulation In Java

This Class will become very usefull when you are dealing with Dates in Java. This class provides method which you can call based on your needs.

File Name : DateManipulation.java

posted under Date, Java | 0 Comments

DateTimeFormater Class usefull while working with dates in java

This Class will become very usefull when you are dealing with Dates in Java. This class provides method which you can call based on your needs.

File Name : DateTimeFormater.java

posted under Date, Java | 0 Comments