JAVA EE: January 2017

Monday, 30 January 2017

Java Tutorial: Java Synchronization (Why we use Synchronization[Bank] | Synchronization in java)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=Pr7NlI7nbFg&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial: Java Synchronization (Why we use Synchronization[Bank] | Synchronization in java)

BankAccount.java

public class BankAccount
{

    private int accountNumber;
    private double accountBalance;
    
    private AccountDAO dao;

    public synchronized boolean deposit(double amount)
    {
        double newAccountBalance;
        /*
         * Get the current balance from DB table.
         */
        accountBalance = dao.getCurrentAccountBalance(accountNumber);
        
        if (amount < 0.0)
        {
            /*
             * Can not deposit a negative amount.
             */
            return false; 
        }

        else
        {
            newAccountBalance = accountBalance + amount;
            /*
             * Update the new balance in the DB table.
             */         
            dao.updateAccountBalance(newAccountBalance);
            return true;
        }

    }
}

AccountDAO.java

public class AccountDAO
{

    public double getCurrentAccountBalance(int accountNumber)
    {
        /*
         * Code to get the current balance from DB table.
         */
        return 0;
    }

    public void updateAccountBalance(double newAccountBalance)
    {
        /*
         * Code to update the new balance in the DB table.
         */ 
        
    }

}

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/SynchronizationDemo_Bank_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/SynchronizationDemo_Bank_App/SynchronizationDemo

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/SynchronizationDemo_Bank_App/SynchronizationDemo/?at=master

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Java Tutorial: Java Synchronization (Java Synchronization | Synchronization in java) - Playlist

Click here to watch in Youtube :
https://www.youtube.com/watch?v=xTBu6iXL8LM&list=PLmCsXDGbJHdhLWV0-HM8eGIa0je7nZJ5I
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Java Tutorial: Java Synchronization (Why we use Synchronization | Synchronization in java)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=Y9vFftRKUEY&list=UUhwKlOVR041tngjerWxVccw

Click the below Image to Enlarge

Java Tutorial: Java Synchronization (Why we use Synchronization | Synchronization in java)

Java Tutorial: Java Synchronization (Java Synchronization | Synchronization in java)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=xTBu6iXL8LM&list=UUhwKlOVR041tngjerWxVccw

Click the below Image to Enlarge

Java Tutorial: Java Synchronization (Java Synchronization | Synchronization in java)

Java Tutorial: Java Runtime class (gc method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=AHhIMs3HAyI&list=UUhwKlOVR041tngjerWxVccw

RuntimeDemo.java

import java.io.IOException;

public class RuntimeDemo
{

    public static void main(String[] args) throws IOException
    {
        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        System.out.println("Runs the Gargage collector..");
        /*
         * Runs the garbage collector.
         * 
         * Calling this method suggests that the Java
         * virtual machine expend effort toward recycling
         * unused objects in order to make the memory they
         * currently occupy available for quick reuse. When
         * control returns from the method call, the virtual
         * machine has made its best effort to recycle all
         * discarded objects.
         * 
         * The name gc stands for "garbage collector". The
         * virtual machine performs this recycling process
         * automatically as needed, in a separate thread,
         * even if the gc method is not invoked explicitly.
         * 
         * The method System.gc() is the conventional and
         * convenient means of invoking this method.
         */
        runtime.gc();

    }

}

Output

Runs the Gargage collector..

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_GC_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_GC_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/RuntimeDemo_GC_App/?at=master

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Java Tutorial: Java Runtime class (halt method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=U0h2VimMOkQ&list=UUhwKlOVR041tngjerWxVccw

RuntimeDemo.java

import java.io.IOException;

/*
 * public void halt(int status)
 * 
 * Parameters: 
 * -----------
 * 
 * status - Termination status. By convention, a nonzero
 * status code indicates abnormal termination.
 */
public class RuntimeDemo
{

    public static void main(String[] args) throws IOException
    {
        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        System.out.println("Before halt method is called..");
        /*
         * Forcibly terminates the currently running Java
         * virtual machine.
         * 
         * This method should be used with extreme caution.
         * Unlike the exit method, this method does not
         * cause shutdown hooks to be started and does not
         * run uninvoked finalizers if finalization-on-exit
         * has been enabled. If the shutdown sequence has
         * already been initiated then this method does not
         * wait for any running shutdown hooks or finalizers
         * to finish their work.
         */
        runtime.halt(0);
        System.out.println("After halt method is called..");
    }

}

Output

Before halt method is called..

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_halt_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_halt_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/RuntimeDemo_halt_App/?at=master

See also:

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Java Tutorial: Java Runtime class (exec(String command,String[] envp,File dir) method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=-AzVJNru9Ls&list=UUhwKlOVR041tngjerWxVccw

RuntimeDemo.java

import java.io.File;
import java.io.IOException;

/*
 * public Process exec(String command, String[] envp,
 *                              File dir) throws IOException
 * 
 * Parameters: 
 * -----------
 * 
 * command - a specified system command.
 * 
 * envp - array of strings, each element of which has
 * environment variable settings in the format
 * name=value, or null if the subprocess should inherit
 * the environment of the current process.
 * 
 * dir - the working directory of the subprocess, or
 * null if the subprocess should inherit the working
 * directory of the current process.
 */

public class RuntimeDemo
{

    public static void main(String[] args) throws IOException
    {
        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        /*
         * Create a file with the working directory we wish
         */
        File dir = new File("D:/Work/");

        /*
         * Executes the specified string command in a
         * separate process with the specified environment
         * and working directory.
         * 
         * It will open a new notepad.
         */
        Process process = runtime.exec("notepad.exe", null, dir);
        System.out.println("is process alive = " + process.isAlive());
    }

}

Output

is process alive = true

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_exec_cmd_envp_dir_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_exec_cmd_envp_dir_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/RuntimeDemo_exec_cmd_envp_dir_App/?at=master

See also:

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Java Tutorial: Java Runtime class (exec(String command,String[] envp) method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=BEARNZg4-SM&list=UUhwKlOVR041tngjerWxVccw

RuntimeDemo.java

import java.io.IOException;

/*
 * public Process exec(String command, String[] envp)
 *                                      throws IOException
 *
 * Parameters:
 * -----------
 *
 * command - a specified system command.
 *
 * envp - array of strings, each element of which has
 * environment variable settings in the format
 * name=value, or null if the subprocess should inherit
 * the environment of the current process.
 */
public class RuntimeDemo
{

    public static void main(String[] args) throws IOException
    {
        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        /*
         * Executes the specified string command in a
         * separate process with the specified environment.
         *
         * It will open a new notepad.
         */
        Process process = runtime.exec("notepad.exe",null);
        System.out.println("is process alive = " + process.isAlive());
    }

}

Output

is process alive = true

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_exec_cmd_envp_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_exec_cmd_envp_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/RuntimeDemo_exec_cmd_envp_App/?at=master

See also:

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Java Tutorial: Java Runtime class (exec(String[] cmdarray,String[] envp,File dir) method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=Irfb6Fru4XQ&list=UUhwKlOVR041tngjerWxVccw

RuntimeDemo.java

import java.io.File;
import java.io.IOException;

/*
 * public Process exec(String[] cmdarray, String[] envp,
 *                              File dir) throws IOException
 * 
 * Parameters: 
 * -----------
 * 
 * cmdarray - array containing the command to call and
 * its arguments.
 * 
 * envp - array of strings, each element of which has
 * environment variable settings in the format
 * name=value, or null if the subprocess should inherit
 * the environment of the current process.
 * 
 * dir - the working directory of the subprocess, or
 * null if the subprocess should inherit the working
 * directory of the current process.
 */
public class RuntimeDemo
{

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

        String[] cmdArray = new String[2];

        cmdArray[0] = "notepad.exe";
        cmdArray[1] = "Hello.txt";

        System.out.println(
                "Executing notepad.exe and opening Hello.txt");

        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        File dir = new File("D:/work");
        /*
         * Executes the specified string command in a
         * separate process with the specified environment
         * and working directory.
         * 
         * Returns: A new Process object for managing the
         * subprocess
         */
        Process process = runtime.exec(cmdArray, null, dir);

        System.out.println("is process alive = " + process.isAlive());
        System.out.println(cmdArray[1] + " should now open.");
    }

}

Output

Executing notepad.exe and opening Hello.txt
is process alive = true
Hello.txt should now open.

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_exec_cmdarray_envp_dir_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_exec_cmdarray_envp_dir_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/RuntimeDemo_exec_cmdarray_envp_dir_App/?at=master

See also:

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Java Tutorial: Java Runtime class (exec(String[] cmdarray, String[] envp) method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=KrGPHOtlq9U&list=UUhwKlOVR041tngjerWxVccw

RuntimeDemo.java

import java.io.IOException;

/*
 * public Process exec(String[] cmdarray, String[] envp)
 *                                      throws IOException
 * 
 * Parameters: 
 * -----------
 * 
 * cmdarray - array containing the command to call and
 * its arguments. 
 * 
 * envp - array of strings, each element
 * of which has environment variable settings in the
 * format name=value, or null if the subprocess should
 * inherit the environment of the current process.
 */

public class RuntimeDemo
{

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

        String[] cmdArray = new String[2];

        cmdArray[0] = "notepad.exe";
        cmdArray[1] = "Hello.txt";

        System.out.println("Executing notepad.exe and opening Hello.txt");

        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        /*
         * Executes the specified command and arguments in a
         * separate process with the specified environment.
         * 
         * Returns: A new Process object for managing the
         * subprocess
         */
        Process process = runtime.exec(cmdArray, null);

        System.out.println("is process alive = " + process.isAlive());
        System.out.println(cmdArray[1] + " should now open.");
    }

}

Output

Executing notepad.exe and opening Hello.txt
is process alive = true
Hello.txt should now open.

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_exec_cmdarray_envp_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_exec_cmdarray_envp_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/RuntimeDemo_exec_cmdarray_envp_App/?at=master

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Java Tutorial: Java Runtime class (exec(String[] cmdarray) method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=dW75MCvPRtI&list=UUhwKlOVR041tngjerWxVccw

RuntimeDemo.java

import java.io.IOException;

/*
 * public Process exec(String[] cmdarray) throws
 *                                      IOException
 * 
 * Parameters: 
 * -----------
 * 
 * cmdarray - array containing the command to call and
 * its arguments.
 */
public class RuntimeDemo
{

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

        String[] cmdArray = new String[2];

        cmdArray[0] = "notepad.exe";
        cmdArray[1] = "Hello.txt";

        System.out.println("Executing notepad.exe and opening Hello.txt");

        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        /*
         * Executes the specified command and arguments in a
         * separate process.
         * 
         * Returns: A new Process object for managing the
         * subprocess
         */
        Process process = runtime.exec(cmdArray);

        System.out.println("is process alive = " + process.isAlive());
        System.out.println(cmdArray[1] + " should now open.");
    }

}

Output

Executing notepad.exe and opening Hello.txt
is process alive = true
Hello.txt should now open.

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_exec_cmdarray_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_exec_cmdarray_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/28b772df8f5b4b9e60fd873726243fc258cd34a2/BasicJava/RuntimeDemo_exec_cmdarray_App/?at=master

See also:

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Friday, 27 January 2017

Java Tutorial: Java Runtime class (How to terminate JVM using exit method)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=vBFQ0N_CFsA&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial: Java Runtime class (How to terminate JVM using exit method)

RuntimeDemo.java

import java.io.IOException;

/*
 * public void exit(int status)
 * 
 * Parameters: 
 * -----------
 * 
 * status - Termination status. By convention, a nonzero
 * status code indicates abnormal termination.
 */
public class RuntimeDemo
{

    public static void main(String[] args) throws IOException
    {
        /*
         * Returns the runtime object associated with the
         * current Java application.
         */
        Runtime runtime = Runtime.getRuntime();

        System.out.println("Before exit method is called..");
        /*
         * Terminates the currently running Java virtual
         * machine by initiating its shutdown sequence..
         */
        runtime.exit(0);

        System.out.println("After exit method is called..");
    }

}

Output

Before exit method is called..

Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/RuntimeDemo_exit_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/RuntimeDemo_exit_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/c72ef0bb7cf33f5c158c45d824df234766210e9a/BasicJava/RuntimeDemo_exit_App/?at=master

See also:

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