JOptionPane

Standard object used to popup messages, ask yes/no questions, and ask for simple input.
In order to use JOptionPane methods, you must tell java that you are going to use the javax.swing libaray. do this using the import statement.
import statements go at the begining of the program.

import javax.swing.JOptionPane;

or

import javax.swing.*;

Methods:

JOptionPane.showMessageDialog

public static void showMessageDialog(Component parentComponent,
                                     Object message,
                                     String title,
                                     int messageType)

Brings up a dialog that displays a message using an icon determined by the messageType parameter.

Parameters:

parentComponent - determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used
message - the Object to display
title - the title string for the dialog
messageType - the type of message to be displayed: ERROR_MESSAGE, INFORMATION_MESSAGE, WARNING_MESSAGE, QUESTION_MESSAGE, or PLAIN_MESSAGE

Example:
    JOptionPane.showMessageDialog(null,"Your computer has a virus","Virus checker",
                                 JOptionPane.ERROR_MESSAGE);


  
public static void showMessageDialog(Component parentComponent, Object message)

Shortened version, brings up a dialog that displays the message and an ok button.
Parameters:

parentComponent - determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used

message - the Object(tex) to display
Example:
            JOptionPane.showMessageDialog(null,"Your computer has a virus");

JOptionPane.showConfirmDialog

public static int showConfirmDialog(Component parentComponent,
                                    Object message,
                                    String title,
                                    int optionType,
                                    int messageType)

Brings up a dialog where the number of choices is determined by the optionType parameter, where the messageType parameter determines the icon to display. The messageType parameter is primarily used to supply a default icon from the Look and Feel.
Parameters:

parentComponent - determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used.
message - the Object to display in the middle of the box, the question to ask
title - the title string for the dialog, text displayed in the blue banner area
optionType - an integer designating the options available on the dialog: YES_NO_OPTION, or YES_NO_CANCEL_OPTION
messageType - an integer designating the kind of message this is; primarily used to determine the icon from the pluggable Look and Feel: ERROR_MESSAGE, INFORMATION_MESSAGE, WARNING_MESSAGE, QUESTION_MESSAGE, or PLAIN_MESSAGE

Returns:
an integer indicating the option selected by the user, YES_OPTION, NO_OPTION, CANCEL_OPTION

Example:

int answer = JOptionPane.showConfirmDialog(null, "Do you want to proceed with the installation","Confirmation", 
                                               JOptionPane.YES_NO_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE);
if(answer == JOptionPane.YES_OPTION)
    System.out.println("You pressed yes");

public static int showConfirmDialog(Component parentComponent, Object message)

Brings up a dialog with the given dialog and the choices Yes, No, Cancel,
Parameters:

parentComponent - determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used.
message - the Object to display in the middle of the box, the question to ask
title - the title string for the dialog, text displayed in the blue banner area

Returns:
an integer indicating the option selected by the user, YES_OPTION, NO_OPTION, CANCEL_OPTION

Example:

int answer = JOptionPane.showConfirmDialog(null, "Do you want to proceed with the installation");
if(answer == JOptionPane.YES_OPTION)
    System.out.println("You pressed yes");

public static int showConfirmDialog(Component parentComponent,
Object message,
String title,
int optionType) Brings up a dialog where the number of choices is determined by the optionType
parameter.

Parameters:

parentComponent - determines the Frame in which the dialog is displayed; if null, or if the parentComponent has no Frame, a default Frame is used.
message - the Object to display in the middle of the box, the question to ask
title - the title string for the dialog, text displayed in the blue banner area
optionType - an integer designating the options available on the dialog: YES_NO_OPTION, or YES_NO_CANCEL_OPTION

Returns:
an integer indicating the option selected by the user, YES_OPTION, NO_OPTION, CANCEL_OPTION

Example:

int answer = JOptionPane.showConfirmDialog(null, "Do you want to proceed with the installation","Confirmation",
JOptionPane.YES_NO_CANCEL_OPTION);
if(answer == JOptionPane.NO_OPTION)
System.out.println("You pressed no");

JOptionPane.showInputDialog

public static String showInputDialog(Component parentComponent,
                                     Object message,
                                     String title,
                                     int messageType)

Shows a file in the box dialog requesting input from the user parented to parentComponent with the dialog having the title title and message type messageType.

Parameters:: parentComponent - the parent Component for the dialog, or null; message - the Object to display; title - the String to display in the dialog title bar; messageType - the type of message that is to be displayed: ERROR_MESSAGE, INFORMATION_MESSAGE, WARNING_MESSAGE, QUESTION_MESSAGE, or PLAIN_MESSAGE

Returns:
String entered by the user.

example:

String answer = JOptionPane.showInputDialog(null,"Please enter your age","Question",JOptionPane.QUESTION_MESSAGE);
int age = Integer.parseInt(answer);
int dogyears = age*7;

System.out.println("You age in dog years is "+dogyears);