Open any file or folder in java

Complete source code will show you, how to open any files or folders using java in windows.What you must know is :


rundll32 SHELL32.DLL,ShellExec_RunDLL File_Or_Folder_To_Open


What is rundll32.exe And Why Is It Running?


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COMPLETE SOURCE CODE FOR : OpenFileUsingJava.java
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public class OpenFileUsingJava
{
public static void main(String[]args)
{
 try
 {
  //Path for folder or file that you want to open
  //In my case i will open C:\ drive
  //So create a String like below
  //Don't forget to change \ to \\
  String a="C:\\";
 
  //Execute command
  //Command that you must know : rundll32 SHELL32.DLL,ShellExec_RunDLL File_Or_Folder_To_Open
  Runtime.getRuntime().exec("rundll32 SHELL32.DLL,ShellExec_RunDLL \""+a+"\"");
 }
 catch(Exception exception)
 {
  exception.printStackTrace();
 }
}
}

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What is different between i++ and ++i

I want to share with you about different between i++ and ++i.

++i
**********
int i=0;
System.out.println(++i);
**********
It will print on screen 1


i++
**********
int i=0;
System.out.println(i++);
**********
It will print on screen 0

Answer :
++i will add current i value with 1 before print


i++ will add current i value with 1 after print

Draw triangle in JPanel

Complete source code below will show you, how to draw triangle in JPanel

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COMPLETE SOURCE CODE FOR : DrawTriangle.java
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import javax.swing.*;

import java.awt.*;

public class DrawTriangle extends JPanel
{
public DrawTriangle()
{
 JFrame frame=new JFrame("Draw triangle in JPanel");
 frame.add(this);

 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 frame.setSize(400,400);
 frame.setLocationRelativeTo(null);
 frame.setVisible(true);
}

public void paint(Graphics g)
{
 super.paint(g);

 //All triangle corner x coordinate
 int[]x={0,150,300};

 //All triangle corner y coordinate
 int[]y={200,0,200};

 //Set color base on RGB
 //You can get RGB value for your color at "Color picker" at above
 //R=255
 //G=192
 //B=0
 //So after this all you draw will use this color
 g.setColor(new Color(255,192,0));

 //Draw triangle in JPanel
 g.fillPolygon(x,y,3);

 //Set color base on RGB
 //You can get RGB value for your color at "Color picker" at above
 //R=1
 //G=1
 //B=1
 //So after this all you draw will use this color
 g.setColor(new Color(1,1,1));

 //Set font that will use when draw String
 g.setFont(new Font("Arial",Font.BOLD,14));

 //Draw String in JPanel
 g.drawString("(0,200)",10,200);
 g.drawString("(150,0)",150,20);
 g.drawString("(300,200)",290,200);
}

public static void main(String[]args)
{
 DrawTriangle dt=new DrawTriangle();
}

}

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Compare current date with user input date in java

Complete source code below will show you, how to compare current date with user input date in java.

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COMPLETE SOURCE CODE FOR : GetDate.java
***************************************************************************

import java.util.Date;

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class GetDate implements ActionListener
{
int year=0;
int month=0;
int date=0;

String [] yearContent={"2000","2001","2002","2003","2004","2005","2006","2007","2008","2009","2010","2011"};
String [] monthContent={"January","February","March","April","Mei","Jun","July","August","September","October","November","December"};
String [] dateContent={"1","2","3","4","5","6","7","8","9","10",
    "11","12","13","14","15","16","17","18","19","20",
    "21","22","23","24","25","26","27","28","29","30",
    "31"};

JComboBox yearComboBox=new JComboBox(yearContent);
JComboBox monthComboBox=new JComboBox(monthContent);
JComboBox dateComboBox=new JComboBox(dateContent);

JButton button=new JButton("Click here to compare to current date");

JFrame frame=new JFrame("Compare date with current date");

public GetDate()
{
button.addActionListener(this);

Box box=Box.createHorizontalBox();
box.add(dateComboBox);
box.add(monthComboBox);
box.add(yearComboBox);

frame.setLayout(new GridLayout(2,1));

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(box);
frame.add(button);
frame.setSize(500,100);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}

public void actionPerformed(ActionEvent event)
{
if(event.getSource()==button)
{
 String tempDate=(String)dateComboBox.getSelectedItem();
 date=Integer.parseInt(tempDate);

 month=monthComboBox.getSelectedIndex();

 String tempYear=(String)yearComboBox.getSelectedItem();
 year=Integer.parseInt(tempYear)-1900;

 Date currentDateValue=new Date();
 Date userChooserDate=new Date(year,month,date);

 int currentYear=currentDateValue.getYear();
 int currentMonth=currentDateValue.getMonth();
 int currentDate=currentDateValue.getDate();

 if((date==currentDate)&&(month==currentMonth)&&(year==currentYear))
 {
  JOptionPane.showMessageDialog(frame,"Same date","SAME",JOptionPane.INFORMATION_MESSAGE);
 }
 else if(userChooserDate.compareTo(currentDateValue)<0)>0)
 {
  JOptionPane.showMessageDialog(frame,"Welcome to the future","FUTURE",JOptionPane.INFORMATION_MESSAGE);
 }
}
}

public static void main(String[]args)
{
GetDate gd=new GetDate();
}
}

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Input box in java

Complete source code below will show you, how to create simple input box that will prompt some input from user. We will use predefined java class, JOptionPane to create simple input box. If you want your input box appear in a container, you can change null in source code below to target container.You can see example by click here.

*************************************************************************
COMPLETE SOURCE CODE FOR : JavaInputDialog.java
*************************************************************************

import javax.swing.JOptionPane;

public class JavaInputDialog
{
public static void main(String[]args)
{
 //Pop up an input box with text ( What is your name ? )
 String a=JOptionPane.showInputDialog(null,"What is your name ?");

 //Print into command prompt what you put into input dialog box
 System.out.println("My name is : "+a);
}
}

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Message box appear in JFrame

Complete source code below will show you, how to make message box appear in a container.

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COMPLETE SOURCE CODE FOR : MessageBoxAppearInJFrame.java
**********************************************************************

import javax.swing.JOptionPane;

import javax.swing.JFrame;

public class MessageBoxAppearInJFrame
{
public static void main(String[]args)
{
 //Create a window using JFrame with title ( Message box appear in JFrame )
 JFrame frame=new JFrame("Message box appear in JFrame");

 //Set default close operation for JFrame
 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 //Set JFrame size
 frame.setSize(400,400);

 //Make JFrame locate at center on screen
 frame.setLocationRelativeTo(null);

 //Make JFrame visible
 frame.setVisible(true);


 //Pop up a message box with text ( I am a message dialog ) in created JFrame
 JOptionPane.showMessageDialog(frame,"I am a message dialog");
}
}

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Create message box in java

Complete source code below will show you, how to create message box in java. We will use JOptionPane class to create message box. If you want your message box appear in a container, you can change null in source code below to target container.You can see example by click here.

************************************************************************
COMPLETE SOURCE CODE FOR : JavaMessageDialog.java
************************************************************************

import javax.swing.JOptionPane;

public class JavaMessageDialog
{
public static void main(String[]args)
{
 //Pop up a message box with text ( I am a message dialog )
 JOptionPane.showMessageDialog(null,"I am a message dialog");
}
}

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Read floating point number user input in java

Complete source code below, will show you how to wait and read floating point number user input in command prompt.

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COMPLETE SOURCE CODE FOR : ReadFloatingPointNumberUserInput.java
********************************************************************

import java.util.Scanner;

public class ReadFloatingPointNumberUserInput
{
public static void main(String[]args)
{
 try
 {
  //Create a scanner object
  //Scanner is a predefined class in java that will be use to scan text
  //System.in is mean, we will receive input from standard input stream
  Scanner readUserInput=new Scanner(System.in);

  //Print into command prompt(Put a floating point number : )
  System.out.print("Put a floating point number : ");

  //Wait and READ FLOATING POINT NUMBER from user input after user hit 'Enter'
  float myPointNumber=readUserInput.nextFloat();

  //Print what store in myPointNumber
  System.out.println("My floating point number is : "+myPointNumber);
 }
 catch(Exception exception)
 {
  //Error that will be print if user put other than floating point number
  System.out.println("Hey !!! Don't put other than floating point number");
 }
}
}

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Read integer user input in java

Complete source code below, will show you how to wait and read integer user input in command prompt.

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COMPLETE SOURCE CODE FOR : ReadIntegerUserInput.java
**********************************************************************

import java.util.Scanner;

public class ReadIntegerUserInput
{
public static void main(String[]args)
{
 try
 {
  //Create a scanner object
  //Scanner is a predefined class in java that will be use to scan text
  //System.in is mean, we will receive input from standard input stream
  Scanner readUserInput=new Scanner(System.in);

  //Print into command prompt(What is your age ?)
  System.out.println("What is your age ?");

  //Wait and READ INTEGER INPUT from user after user hit 'Enter'
  int myAge=readUserInput.nextInt();

  //Print what store in myAge
  System.out.println("Your age is : "+myAge);
 }
 catch(Exception exception)
 {
  //Error that will be print if user put other than number include
  //point number
  System.out.println("Hey !!! Don't put other than number");
 }
}
}

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Read a word user input in java

Complete source code below, will show you how to wait and read only a word from user input in command prompt.

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COMPLETE SOURCE CODE FOR : ReadOneWordUserInput.java
*****************************************************************

import java.util.Scanner;

public class ReadOneWordUserInput
{
public static void main(String[]args)
{
 //Create a scanner object
 //Scanner is a predefined class in java that will be use to scan text
 //System.in is mean, we will receive input from standard input stream
 Scanner readUserInput=new Scanner(System.in);

 //Print into command prompt(What is your gender ?)
 //Print into command prompt(Female/Male)
 System.out.println("What is your gender ?\nFemale/Male");

 //Wait and READ A WORD from user input after user hit 'Enter'
 //Method next() in class scanner will read only first word in user input
 //So, second word that seperate by space will be ignore.
 String myGender=readUserInput.next();

 //Print what store in myGender
 System.out.println(myGender);
}
}

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