JOptionPane is a easy way to do dialog boxes, messages or inputs.
You have to import it at the beginning of the program:

Java:
import javax.swing.JOptionPane;

The arguments for JOptionPane:

for a simple message box:

Java:
JOptionPane.showMessageDialog (
null, “Put your message here” );to show text in different rows:

JOptionPane.showMessageDialog (
null, “Put \nyour \nmessage \nhere” );

the \n switches to next line

Sample program:

Java:
//A sample program. Sample.java
import javax.swing.JOptionPane; // imports JOptionPane classpublic class Sample {
public static void main ( String args[] )
{
JOptionPane.showMessageDialog (
null, “This is a sample program” );

System.exit ( 0 ); //stops the program
}
}

To show different messages with different icons, you’ll need 4 arguments instead of 2.

Java:
JOptionPane.showMessageDialog (
null, “Messagehere”, “Title here”, JOptionPane.PLAIN_MESSAGE);

There are different kinds of icons for a dialog box, just replace the last argument:

Java:
JOptionPane.PLAIN_MESSAGE // this is a plain message
JOptionPane.INFORMATION_MESSAGE // this is a info message
JOptionPane.ERROR_MESSAGE // this is a error message
JOptionPane.WARNING_MESSAGE // this is a warning message

You can also use JOptionPane for dialog boxes for input, and assign them to variables, just put:

Java:
name=   // The variable
JOptionPane.showInputDialog ( “put your message here” );

note: after using JOptionPane, dont forget to exit System.exit

Sample Program:

Java:
// Addition.java
// An addition programimport javax.swing.JOptionPane; //import class JOptionPane

public class Addition {
public static void main ( String args[] )
{
String firstNumber, //first string entered by user
secondNumber; // second string entered by user

int number1,     // first number to add
number2,    //second number to add
sum;                //sum of number1 and number2

//read in the first number from user as a string
firstNumber =
JOptionPane.showInputDialog ( “Enter first integer” );

//read in the second number from user as a string
secondNumber =
JOptionPane.showInputDialog ( “Enter second interger” );

//convert numbers from type String to type int
number1 = Integer.parseInt ( firstNumber);
number2 = Integer.parseInt ( secondNumber);

//add the numbers
sum = number1 + number2;

//display the results
JOptionPane.showMessageDialog (
null, “The sum is ” + sum, “Results”,
JOptionPane.PLAIN_MESSAGE);
System.exit ( 0 ); //ends the program
}
}

NOTE:
JOptionPane can ONLY be used to input string, so if you want to use numbers, you have to create separate variables to change it into integers, or real numbers.

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