Use a method from another class in another package?

How can I use a method from another class in another package?

WhiteJ wrote:
What do you mean by "new keyword?" You posted this previously:
I tried that, it seems to not be working. I want to use the constructor from the other class. I imported it, using this piece of code:
import components.FileChooser;
components.FileChoser();
Typically if I am going to call a constructor on a class called Fubar, I'd use new to create a new object:
Fubar myFubar = new Fubar();Incidently, is it a simple typo in your post or are you trying to use a FileChoser object when it should be FileChooser?

Similar Messages

Using a method from a class into another

Hello,
I have two classes that do separate things , one makes a checkboard and the other one creates a fading effect, and i would like to know how can i modify the first one in order for the black rectangles of the checkerboard to have a fading effect, only the black ones.
Checkerboard
import java.awt.Frame;
import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.AWTEvent;
import java.awt.event.WindowEvent;
public class DrawCheckerboard extends Frame {
public static void main(String arg[]) {
new DrawCheckerboard();
DrawCheckerboard() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
Checkerboard checkerboard = new Checkerboard();
add(checkerboard);
pack();
show();
public void processWindowEvent(WindowEvent event) {
if(event.getID() == WindowEvent.WINDOW_CLOSING)
System.exit(0);
class Checkerboard extends Canvas {
Checkerboard() {
setSize(256,256);
public void paint(Graphics g) {
for(int i=0; i<4; i++) {
for(int j=0; j<4; j++) {
if(((i+j) & 1) == 0) {
int x = i * 64;
int y = j * 64;
g.fillRect(x,y,64,64);
Fade
import java.awt.Frame;
import java.awt.Canvas;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.AWTEvent;
import java.awt.event.WindowEvent;
public class DrawFade extends Frame {
public static void main(String arg[]) {
new DrawFade();
DrawFade() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
Fade fade = new Fade();
add(fade);
pack();
show();
public void processWindowEvent(WindowEvent event) {
if(event.getID() == WindowEvent.WINDOW_CLOSING)
System.exit(0);
class Fade extends Canvas {
Fade() {
setSize(400,300);
public void paint(Graphics g) {
int x = 0;
int y = 0;
int width = 2;
int height = 400;
Color color = new Color(100,50,150);
while(x < 400) {
g.setColor(color);
g.fillRect(x,y,width,height);
x += width;
int red = color.getRed();
int green = color.getGreen();
int blue = color.getBlue();
if(++red > 255)
red = 255;
if(++green > 255)
green = 255;
if(++blue > 255)
blue = 255;
color = new Color(red,green,blue);
}

Looks more or less like reinventing the wheel.
The wheel in this case being java.awt.GradientPaint.
db

Moving a method from one class to another issues

Hi, im new. Let me explain what i am trying to achieve. I am basically trying to move a method from one class to another in order to refactor the code. However every time i do, the program stops working and i am struggling. I have literally tried 30 times these last two days. Can some one help please? If shown once i should be ok, i pick up quickly.
Help would seriously be appreciated.
Class trying to move from, given that this is an extraction:
class GACanvas extends Panel implements ActionListener, Runnable {
private WorldMenuItems speedMenuItems, designMenuItemsPlantGrowth, designMenuItemsPlantCount;
     private WorldMenuItems designMenuItemsPlantEaten, designMenuItemsApproximatePopulation;
     private WorldMenuItems designMenuItemsEatersBorn,designMenuItemsMutationProbability;
     private WorldMenuItems designMenuItemsCrossoverProbability;
MenuBar getMenuBar() {
          menuBar = new MenuBar();
          addControlItemsToMenuBar();
          addSpeedItemsToMenuBar();
          addWorldDesignItemsToMenuBar();
          return menuBar;
This is the method i am trying to move (below)
public void itemsInsideWorldDesignMenu() {
          designMenuItemsPlantGrowth = new WorldMenuItems("Plants Grow",
                    new String[] { "In Rows", "In Clumps", "At Random",
                              "Along the Bottom", "Along the Edges" }, 1);
          designMenuItemsPlantCount = new WorldMenuItems("Number Of Plants",
                    new String[] { "50", "100", "150", "250", "500" }, 3);
          designMenuItemsPlantEaten = new WorldMenuItems("When a Plant is Eaten",
                    new String[] { "It grows back somewhere",
                              "It grows back nearby", "It's Gone" }, 0);
          designMenuItemsApproximatePopulation = new WorldMenuItems(
                    "Approximate Population", new String[] { "10", "20", "25",
                              "30", "40", "50", "75", "100" }, 2);
          designMenuItemsEatersBorn = new WorldMenuItems("Eaters are Born",
                    new String[] { "At the Center", "In a Corner",
                              "At Random Location", "At Parent's Location" }, 2);
          designMenuItemsMutationProbability = new WorldMenuItems(
                    "Mutation Probability", new String[] { "Zero", "0.25%", "0.5%",
                              "1%", "2%", "3%", "5%", "10%" }, 3);
          designMenuItemsCrossoverProbability = new WorldMenuItems(
                    "Crossover Probability", new String[] { "Zero", "10%", "25%",
                              "50%", "75%", "100%" }, 4);
Class Trying to move to:
class WorldMenuItems extends Menu implements ItemListener {
   private CheckboxMenuItem[] items;
   private int selectedIndex = -1;
   WorldMenuItems(String menuName, String[] itemNames) {
      this(menuName, itemNames, -1);
   WorldMenuItems(String menuName, String[] itemNames, int selected) {
      super(menuName);
      items = new CheckboxMenuItem[itemNames.length];
      for (int i = 0; i < itemNames.length; i++) {
         items[i] = new CheckboxMenuItem(itemNames);
add(items[i]);
items[i].addItemListener(this);
selectedIndex = selected;
if (selectedIndex < 0 || selectedIndex >= items.length)
selectedIndex = 1;
items[selectedIndex].setState(true);
     public int getSelectedIndex() {
          return selectedIndex;
public void itemStateChanged(ItemEvent evt) { // This works on other systems
CheckboxMenuItem newSelection = (CheckboxMenuItem)evt.getSource();
for (int i = 0; i < items.length; i++) {
if (newSelection == items[i]) {
items[selectedIndex].setState(false);
selectedIndex = i;
newSelection.setState(true);
return;

Ok i've done this. I am getting an error on the line specified. Can someone help me out and tell me what i need to do?
GACanvas
//IM GETTING AN ERROR ON THIS LINE UNDER NAME, SAYING IT IS NOT VISIBLE
WorldMenuItems worldmenuitems = new WorldMenuItems(name, null);
public MenuBar getMenuBar() {
          menuBar = new MenuBar();
          addControlItemsToMenuBar();
          addSpeedItemsToMenuBar();
          worldmenuitems.addWorldDesignItemsToMenuBar();
          return menuBar;
class WorldMenuItems extends Menu implements ItemListener {
     private WorldMenuItems speedMenuItems, designMenuItemsPlantGrowth, designMenuItemsPlantCount;
     private WorldMenuItems designMenuItemsPlantEaten, designMenuItemsApproximatePopulation;
     private WorldMenuItems designMenuItemsEatersBorn,designMenuItemsMutationProbability;
     private WorldMenuItems designMenuItemsCrossoverProbability;
     GACanvas gacanvas = new GACanvas(null);
   private CheckboxMenuItem[] items;
   private int selectedIndex = -1;
   WorldMenuItems(String menuName, String[] itemNames) {
      this(menuName, itemNames, -1);
   WorldMenuItems(String menuName, String[] itemNames, int selected) {
      super(menuName);
      items = new CheckboxMenuItem[itemNames.length];
      for (int i = 0; i < itemNames.length; i++) {
         items[i] = new CheckboxMenuItem(itemNames);
add(items[i]);
items[i].addItemListener(this);
selectedIndex = selected;
if (selectedIndex < 0 || selectedIndex >= items.length)
selectedIndex = 1;
items[selectedIndex].setState(true);
     public int getSelectedIndex() {
          return selectedIndex;
public void itemStateChanged(ItemEvent evt) { // This works on other systems
CheckboxMenuItem newSelection = (CheckboxMenuItem)evt.getSource();
for (int i = 0; i < items.length; i++) {
if (newSelection == items[i]) {
items[selectedIndex].setState(false);
selectedIndex = i;
newSelection.setState(true);
return;
public void itemsInsideWorldDesignMenu() {
     designMenuItemsPlantGrowth = new WorldMenuItems("Plants Grow",
               new String[] { "In Rows", "In Clumps", "At Random",
                         "Along the Bottom", "Along the Edges" }, 1);
     designMenuItemsPlantCount = new WorldMenuItems("Number Of Plants",
               new String[] { "50", "100", "150", "250", "500" }, 3);
     designMenuItemsPlantEaten = new WorldMenuItems("When a Plant is Eaten",
               new String[] { "It grows back somewhere",
                         "It grows back nearby", "It's Gone" }, 0);
     designMenuItemsApproximatePopulation = new WorldMenuItems(
               "Approximate Population", new String[] { "10", "20", "25",
                         "30", "40", "50", "75", "100" }, 2);
     designMenuItemsEatersBorn = new WorldMenuItems("Eaters are Born",
               new String[] { "At the Center", "In a Corner",
                         "At Random Location", "At Parent's Location" }, 2);
     designMenuItemsMutationProbability = new WorldMenuItems(
               "Mutation Probability", new String[] { "Zero", "0.25%", "0.5%",
                         "1%", "2%", "3%", "5%", "10%" }, 3);
     designMenuItemsCrossoverProbability = new WorldMenuItems(
               "Crossover Probability", new String[] { "Zero", "10%", "25%",
                         "50%", "75%", "100%" }, 4);
public void addWorldDesignItemsToMenuBar() {
     gacanvas = new GACanvas(null);
     itemsInsideWorldDesignMenu();
     Menu designMenuItems = new Menu("WorldDesign");
     designMenuItems.add(designMenuItemsPlantGrowth);
     designMenuItems.add(designMenuItemsPlantCount);
     designMenuItems.add(designMenuItemsPlantEaten);
     designMenuItems.add(designMenuItemsApproximatePopulation);
     designMenuItems.add(designMenuItemsEatersBorn);
     designMenuItems.add(designMenuItemsMutationProbability);
     designMenuItems.add(designMenuItemsCrossoverProbability);
     gacanvas.menuBar.add(designMenuItems);

Using Variables/Arrays from one class in another

Hello all,
First, to explain what I am attempting to create, is a program that will accept input of employee names and hours worked into an array. The first class will accept a command line argument when invoked. If the argument is correct, it will call another class that will gather information from the user via an input box. After all names and hours have been input for employees, this class will calculate the salary based upon the first letter of each employee name and print the total hours, salary, etc. for each employee.
What I need to do now is to split the second class into two: one that will gather the data and another that will calculate and print the data. Yes, this is an assignment. However, I am trying to learn and I have gotten this far, but I am stuck on how to get a class to be able to use an array/variables from another class.
I realize the below code isn't exactly cleaned up...yet.
Code for AverageSalaryGather class:
import javax.swing.JOptionPane; // uses class JOptionPane
import java.lang.reflect.Array;
import java.math.*;
public class AverageSalaryGather {
     public static void gatherData() {
          char[] alphaArray = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','x','y','z'};
          String[][] empInfoArray = new String[100][4];
          String[] empNameArray = new String[100];
          String finalOutput = "Name - Rate - Hours - Total Pay\n";
          String averageHoursOutput = "Average Hours Worked:\n";
          String averageSalaryOutput = "Average Hourly Salary:\n";
          String averageGroupSalaryOutput = "Average Group Salary:\n";
                    String[] rateArray = new String[26];
                    char empNameChar = 'a';
          int empRate = 0;
          int payRate = 0;
                    for (int i = 0; i < 26; i++) {
               payRate = i + 5;
               rateArray[i] = Integer.toString(payRate);
                    int countJoo = 0;
          while (true) {
               String namePrompt = "Please enter the employee name: ";
               String empName = JOptionPane.showInputDialog(namePrompt);
                              if (empName == null | empName.equals("")) {
                    break;
               else {
                    empInfoArray[countJoo][0] = empName;
                    for (int i = 0; i < alphaArray.length; i++) {
                         empNameChar = empName.toLowerCase().charAt(0);
                                                  if (alphaArray[i] == empNameChar) {
                              empInfoArray[countJoo][1] = rateArray;
                              break;
                    countJoo++;
          // DecimalFormat dollarFormat = new DecimalFormat("$#0.00");
          for (int i = 0; i < empInfoArray.length; i++) {
               if (!(empInfoArray[i][0] == null)) {
                    String hourPrompt = "Please enter hours for " + empInfoArray[i][0] + ": ";
                    String empHours = JOptionPane.showInputDialog(hourPrompt);
                    int test = 0;
                    empInfoArray[i][2] = empHours;
                    // convert type String to double
                    //double tmpPayRate = Double.parseDouble(empInfoArray[i][1]);
                    //double tmpHours = Double.parseDouble(empInfoArray[i][2]);
                    //double tmpTotalPay = tmpPayRate * tmpHours;
                    // create via a string in empInfoArray
                         BigDecimal bdRate = new BigDecimal(empInfoArray[i][1]);
                         BigDecimal bdHours = new BigDecimal(empInfoArray[i][2]);
                         BigDecimal bdTotal = bdRate.multiply(bdHours);
                         bdTotal = bdTotal.setScale(2, RoundingMode.HALF_UP);
                         String strTotal = bdTotal.toString();
                         empInfoArray[i][3] = strTotal;
                    //String strTotalPay = Double.toString(tmpTotalPay);
                    //empInfoArray[i][3] = dollarFormat.format(tmpTotalPay);
                    else {
                         break;
          AverageSalaryCalcAndPrint averageSalaryCalcAndPrint = new AverageSalaryCalcAndPrint();
          averageSalaryCalcAndprint.calcAndPrint();
Code for AverageSalaryCalcAndPrint class (upon compiling, there are more than a few complie errors, and that is due to me cutting/pasting the code from the other class into the new class and the compiler does not know how to access the array/variables from the gatherData class):
import javax.swing.JOptionPane; // uses class JOptionPane
import java.lang.reflect.Array;
import java.math.*;
public class AverageSalaryCalcAndPrint
     public static void calcAndPrint() {
          AverageSalaryGather averageSalaryGather = new AverageSalaryGather();
          double totalHours = 0;
          double averageHours = 0;
          double averageSalary = 0;
          double totalSalary = 0;
          double averageGroupSalary = 0;
          double totalGroupSalary = 0;
          int countOfArray = 0;
          for (int i = 0; i < empInfoArray.length; i++) {
               if (!(empInfoArray[0] == null)) {
                    totalSalary = totalSalary + Double.parseDouble(empInfoArray[i][1]);
                    totalHours = totalHours + Double.parseDouble(empInfoArray[i][2]);
                    totalGroupSalary = totalGroupSalary + Double.parseDouble(empInfoArray[i][3]);
                    countOfArray = i;
          averageHours = totalHours / (countOfArray + 1);
          averageSalary = totalSalary / (countOfArray + 1);
          averageGroupSalary = totalGroupSalary / (countOfArray + 1);
          String strAverageHourlySalary = Double.toString(averageSalary);
          String strAverageHours = Double.toString(averageHours);
          String strAverageGroupSalary = Double.toString(averageGroupSalary);
          for (int i = 0; i < empInfoArray.length; i++) {
               if (!(empInfoArray[i][0] == null)) {
                    finalOutput = finalOutput + empInfoArray[i][0] + " - " + "$" + empInfoArray[i][1] + "/hr" + " - " + empInfoArray[i][2] + " - " + "$" + empInfoArray[i][3] + "\n";
          averageHoursOutput = averageHoursOutput + strAverageHours + "\n";
          averageSalaryOutput = averageSalaryOutput + strAverageHourlySalary + "\n";
          averageGroupSalaryOutput = averageGroupSalaryOutput + strAverageGroupSalary + "\n";
          JOptionPane.showMessageDialog(null, finalOutput + averageHoursOutput + averageSalaryOutput + averageGroupSalaryOutput, "Totals", JOptionPane.PLAIN_MESSAGE );

Call the other class's methods. (In general, you
shouldn't even try to access fields from the other
class.) Also you should be looking at an
instance of the other class, and not the class
itself, generally.Would I not call the other classes method's by someting similar as below?:
AverageSalaryCalcAndPrint averageSalaryCalcAndPrint = new AverageSalaryCalcAndPrint();
          averageSalaryCalcAndprint.calcAndPrint(); Well... don't break down classes based on broad steps
of the program. Break them down by the information
being managed. I'm not expressing this well...Could you give an example of this? I'm not sure I'm following well.
Anyway, you want one or more objects that represent
the data, and operations on that data. Those
operations include calculations on the data. Other
classes might represent the user interface, and
different output types (say, a file versus the
console).Yes, the requirements is to have a separate class to gather the data, and then another class to calculate and print the data. Is this what you mean in the above?

Using a variable from one class to another

Hi !
I've a class called ModFam (file ModFam.java) where I define a variable as
protected Connection dbconn;
Inside ModFam constructor I said:
try
String url = "jdbc:odbc:baselocal";
Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
dbconn = DriverManager.getConnection(url);
System.err.println("Connection successful");
} ..... rest of code
This class define a TabbedPane as follows:
tabbedPane.addTab("Welcome",null,new Familias(),"Familias");
As you can see it call a new instance of the Familias class (file Familias.java).
This constructor will try to connect with the DB to populate a combo box with some data retireved from the DB.
If I do
Statement stmt;
stmt = dbconn.createStatement();
inside Familias constructor I receive the message
Familias.java:50: cannot resolve symbol
symbol : variable dbconn
location: class fam.Familias
stmt = dbconn.createStatement();
at compile time.
While I can�t use a variable defined as "protected" in one class of my package on another class of the same package ?
How could I do ?
Thanks in advance
<jl>

Familias doesn't have a reference to ModFam or the Connection.
So change the constructor in Familias to be
public class Familias {
private ModFam modFam;
public Familias(ModFam m) {
modFam = m;
// ... somewhere else in the code
Statement stmt = modFam.dbconn.createStatement();
}or
public class Familias {
private Connection dbconn;
public Familias(Connection c) {
dbconn = c;
// ... somewhere else in the code
Statement stmt = dbconn.createStatement();
}And when you instantiate Familias it should then be
new Familias(this) // ModFam reference
or
new Familias(dbconn)

Using an int from one class in another class

I am a student writing a java program on renewable energy. Simply I have a power output which is a variable called PowerOutPut. declared as (public int PowerOutPut) I have another class which is a graphics class where I display the variable PowerOutPut on a graph, but i dont know how to call this variable in my graphics class.
if anyone can help, I would be very grateful.
Chris

But bear in mind that it is good practice to declare your variables private (unless you need otherwise) and to provide get and set methods to access and change them.
private int myVariable = 0;
public int getMyVariable(){
return myVariable;
public void setMyVariable(int newValue){
myVariable = newValue;
}Also, class names should start with upper case and variables should start with lower case.
Good luck.

Use a counter from one class to another class of the same project

Hello!
In my class Book I have a variable, which is in fact a counter, counts the number of books. I need to use this same variable in another class Library, and I want to know if this is possible by any means!
Thank You very much for Your support!

Read this carefully.
Regards,

Using a variable from one class in another

For learning purposes, I thought I'd have a stab at making a role-playing RPG.
The first class I made was the Player class;
public class Player
     public static void main(String[] args)
          // [0] being base points and [1] being skill points
          int[] points = {50, 10};
          // Elements in statNames are relevent to stats, so stats[0] is health, and so on
          String[] statNames = {"Health", "Mana", "Attack", "Magic", "Craft"};
          int[] stats = new int[5];
     public static String setName()
          Scanner input = new Scanner(System.in);
          System.out.print("Character name: ");
          String name = input.nextLine();
          return name;
     public static void setHealth(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Health (" + points[0] + " base points remanining): ");
          stats[0] = input.nextInt();
          points[0] -= stats[0];
        public static void setMana(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Mana (" + points[0] + " base points remanining): ");
          stats[1] = input.nextInt();
          points[0] -= stats[1];
     public static void setAttack(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Attack (" + points[1] + " skill points remanining): ");
          stats[2] = input.nextInt();
          points[1] -= stats[2];
     public static void setMagic(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Magic (" + points[1] + " skill points remanining): ");
          stats[3] = input.nextInt();
          points[1] -= stats[3];
     public static void setCraft(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Craft (" + points[1] + " skill points remanining): ");
          stats[4] = input.nextInt();
          points[1] -= stats[4];
     public static void setStats(int[] points, int[] stats)
          setHealth(points, stats);
          setMana(points, stats);
          setAttack(points, stats);
          setMagic(points, stats);
          setCraft(points, stats);
     public static void charSummary(String name, String[] statNames, int[] stats)
          System.out.println("\n------ " + name);
          for(int index = 0; index < stats.length; index++)
               System.out.println(statNames[index] + ":\t" + stats[index]);
}And that would be used in the Play class;
public class Play
     public static void main(String[] args)
          Player player = new Player();
          String name = player.setName();
          player.setStats(points, stats);
     }     But I'm not sure how the Play class will get the arrays from the Player class. I tried simply putting public in front of the them, for example;
public String[] statNames = {"Health", "Mana", "Attack", "Magic", "Craft"};But I get an illegal start of expression error.
I may have taken the wrong approach to this all together, I'm completely new, so feel free to suggest anything else. Sorry for any ambiguity.
Edited by: xcd on Jan 6, 2010 8:12 AM
Edited by: xcd on Jan 6, 2010 8:12 AM

HI XCD ,
what about making Player class as
public class Player
          // [0] being base points and [1] being skill points
          int[] points = {50, 10};
          // Elements in statNames are relevent to stats, so stats[0] is health, and so on
          public String[] statNames = {"Health", "Mana", "Attack", "Magic", "Craft"};
          int[] stats = new int[5];
     public String setName()
          Scanner input = new Scanner(System.in);
          System.out.print("Character name: ");
          String name = input.nextLine();
          return name;
     public void setHealth(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Health (" + points[0] + " base points remanining): ");
          stats[0] = input.nextInt();
          points[0] -= stats[0];
        public void setMana(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Mana (" + points[0] + " base points remanining): ");
          stats[1] = input.nextInt();
          points[0] -= stats[1];
     public void setAttack(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Attack (" + points[1] + " skill points remanining): ");
          stats[2] = input.nextInt();
          points[1] -= stats[2];
     public void setMagic(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Magic (" + points[1] + " skill points remanining): ");
          stats[3] = input.nextInt();
          points[1] -= stats[3];
     public void setCraft(int[] points, int[] stats)
          Scanner input = new Scanner(System.in);
          System.out.print("Craft (" + points[1] + " skill points remanining): ");
          stats[4] = input.nextInt();
          points[1] -= stats[4];
     public void setStats(int[] points, int[] stats)
          setHealth(points, stats);
          setMana(points, stats);
          setAttack(points, stats);
          setMagic(points, stats);
          setCraft(points, stats);
     public void charSummary(String name, String[] statNames, int[] stats)
          System.out.println("\n------ " + name);
          for(int index = 0; index < stats.length; index++)
               System.out.println(statNames[index] + ":\t" + stats[index]);
     }and Play class
public class Play
     public static void main(String[] args)
          Player player = new Player();
          String name = player.setName();
          player.setStats(points, stats);
     }Now you can access names , you can't assign keyword to variable into method scope , make it class variable .
Hope it help :)

Calling Parameterized Method from one class to another class

Hi, below is my sample code
test.java
public class test
     int op1[][]=new int[][]{{1,2},{2,3},{4,5}};
     int row=0;
    public void test() {
          int op2[][]=new int[][]{{2,3},{4,5},{6,7}};
                         row=1010;
          getRow(row);
    int[][] getList()
         return op1;
   public int getRow(int klm)
         System.out.println("Row Value in GetRow Method is:     "+row);
         return klm;
test_2.java
package aa;
public class test_2
int a;
     test t11=new test();
     int abc[][] = t11.getList();
     int rowCount=t11.getRow(a);
     public void test_2()
          System.out.println("Row Value is:     "+rowCount);
          System.out.println("Value in abc[1][1] is:     "+abc[0][1]);
main_class.java
package aa;
public class main_class {
     public static void main(String args[])
          test ab=new test();
          ab.test();
          test_2 ba=new test_2();
          ba.test_2();
    public main_class() {
}now that my question is,for 'rowCount' in class test_2.java i need to get the value of 'row'(which is 1010)from class test.java. How could that be done?
Any reply is highly appreciable.
Thanks in advance

netbeans2eclipse wrote:
hmm, i did chaged the test object in main method to same as the test object that i used in test_2 (ie; i changed test ab=new test() in main_class.java to test t1=new test()).What? How does this help?
Again, simplify the problem
For instance, say you have a class, Fubar1, like so:
class Fubar1
int value = 0;
public void setValue(int v)
    value = v;
public int getValue()
    return value;
}and two different Fubar2 classes, both which try to get the value from Fubar1, one doing it badly:
class Fubar2Bad
Fubar1 f1 = new Fubar1(); // totally internal Fubar1 object
public int getFubar1Value()
    return f1.getValue();
}and one that does it well, that holds a reference to whatever Fubar1 object is passed to it:
class Fubar2Good
Fubar1 f1;
public Fubar2Good(Fubar1 f1)
    this.f1 = f1;
public int getFubar1Value()
    return f1.getValue();
}Then if you test these:
public class TestFubars
public static void main(String[] args)
    Fubar1 f1 = new Fubar1();
    f1.setValue(35);
    Fubar2Bad f2Bad = new Fubar2Bad();
    Fubar2Good f2Good = new Fubar2Good(f1); // here we pass a reference to the main's Fubar1 object into the Fubar2Good object.
    System.out.println("Bad: " + f2Bad.getFubar1Value());
    System.out.println("Good: " + f2Good.getFubar1Value());
}

Using enum's from one class in another?

heya,
I have two classes, Predator and Simulation, and Predator has an public enum 'target' inside it.
Simulation needs to use a switch statement based on target (Simulation contains a list of Predators, and I'm returning type target to Simulation), but I am getting errors when compiling the two classes from the commandline (for some weird reason, it works fine in Eclipse - both classes are in a package 'lepidoptera', which I originally thoguht was the issue).
Errors are like (5 of these):
Simulation.java:64: an enum switch case label must be the unqualified name of an enumeration constant
                case (mimic):Any ideas?
Thanks,
Victor

This works for moi:
public class Predator {
    public enum Target {SEITAN, TOFU, TEMPEH}
public class Simulation {
    public static String f(Predator.Target target) {
        switch(target) {
            case SEITAN:
                return "yuck";
            case TOFU:
                return "ugh";
            case TEMPEH:
                return "crikey";
            default:
                return "nuts";
    public static void main(String[] args) {
        System.out.println(f(Predator.Target.SEITAN));
        System.out.println(f(Predator.Target.TOFU));
        System.out.println(f(Predator.Target.TEMPEH));
}And do you know that an enum can be a top level class? In other
words, that you can create the one-line file Target.java:
public enum Target {SEITAN, TOFU, TEMPEH}

Using my Method from my Class (clearer explanation)

I wrote a class called day. With some methods that perform simple operations. Here is a simple one that prints the day of the week:
public void printDay()
System.out.print("Day of the week is "+ day);
My question is:
How do I call this method in a new program ?

I wrote a class called day. With some methods that
perform simple operations. Here is a simple one that
prints the day of the week:
public void printDay()
System.out.print("Day of the week is "+ day);
My question is:
How do I call this method in a new program ?Mate, i'm hardly an expert, but what you probably want to do is instantiate an object of your class in the class that will use it. That means, for an object called "myDay" or whatever else:
Day myDay = new Day();you can then call your method through the object:
myDay.printDay();hope that's helpful somehow.

Call methods from view controller to another (enhanced) view controller!

Dear All,
Is it possible to use/call methods from view controller to another (enhanced) view controller? Iu2019ve created a view using enhancement in standard WD component. I would like to call one method from standard view controller in the enhanced view controller.
Is it possible to include text symbols as enhancement in standard class?
u2026Naddy

Hi,
If you have just enhanced an existing view then you can call the standard methods in one of the new methods which you will create as part of enhancement.
If you have created a totally new view using enhancement framework option ( Create as Enhancement ) then in this new view you won't be able to use existing methods in other view as a view controller is private in nature. So all the view attributes, context nodes and methods are Private to that view only.
Regarding text elements, I guess adding a new text element is just a table entry in text table and is therefore not recorded as enhancement.( Not very sure about this, need to double check )
Regards
Manas Dua

Calling a drawLine() from one class to another from an ActionEvent

I have several JPanel objects called and placed on a JFrame. The JFrame has a RadioButton group with radio buttons. If I select a radio button and call a drawLine() method from a JPanel, I receive a "NullPointerException". Is it not possible to call this graphic method from one class to another?
Thanks for any input you can provide.
John

Remember that each panel draws it's own current state. So you need the ActionPerformed to change the state in your target panel.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.*;
public class PanelComm extends JPanel {
private SubPanelOne subPanelOne = new SubPanelOne();
private SubPanelTwo subPanelTwo = new SubPanelTwo();
public class SubPanelOne extends JPanel {
    public SubPanelOne () {
      setLayout ( new BorderLayout() );
      setBorder ( BorderFactory.createTitledBorder ( "SubPanel One" ) );
      Reactor     reactor    = new Reactor();
      ButtonGroup group      = new ButtonGroup();
      JPanel      radioPanel = new JPanel(new GridLayout(0, 1));
      JRadioButton buttonOne = new JRadioButton ( "One" );
      buttonOne.addActionListener ( reactor );
      group.add ( buttonOne );
      radioPanel.add ( buttonOne );
      JRadioButton buttonTwo = new JRadioButton ( "Two" );
      buttonTwo.addActionListener ( reactor );
      group.add ( buttonTwo );
      radioPanel.add ( buttonTwo );
      JRadioButton buttonThree = new JRadioButton ( "Three" );
      buttonThree.addActionListener ( reactor );
      group.add ( buttonThree );
      radioPanel.add ( buttonThree );
      add ( radioPanel ,BorderLayout.LINE_START );
    protected void paintComponent ( Graphics _g ) {
      super.paintComponent ( _g );
      Graphics2D g = (Graphics2D)_g;
      g.setRenderingHint ( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON );
public class SubPanelTwo extends JPanel {
    private JLabel text = new JLabel();
    public SubPanelTwo () {
      setLayout ( new BorderLayout() );
      setBorder ( BorderFactory.createTitledBorder ( "SubPanel Two" ) );
      text.setFont ( new Font ( "Verdana" ,Font.PLAIN ,30 ) );
      text.setHorizontalAlignment ( JLabel.CENTER );
      add ( text ,BorderLayout.CENTER );
    protected void paintComponent ( Graphics _g ) {
      super.paintComponent ( _g );
      Graphics2D g = (Graphics2D)_g;
      g.setRenderingHint ( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON );
    public void setChoice ( String cmd ) {
      text.setText ( cmd );
public class Reactor implements ActionListener {
    public void actionPerformed ( ActionEvent e ) {
      subPanelTwo.setChoice ( e.getActionCommand() );
public PanelComm () {
    setLayout ( new GridLayout ( 1 ,2 ) );
    add ( subPanelOne );
    add ( subPanelTwo );
// main
public static void main ( String[] args ) {
    JFrame f = new JFrame ( "Panel Communication" );
    f.setDefaultCloseOperation ( JFrame.EXIT_ON_CLOSE );
    f.getContentPane().add ( new PanelComm() ,BorderLayout.CENTER );
    f.setSize ( 320 ,120 );
    f.setVisible ( true );
} // main
}

Doubt on exec method from Process class

i want to use exec method from Process class to run an external exe.
now the problem is that Process is an abstract class and hence cant be instantiated.nor can i access exec method directly even though i import the required packages as its not static.how can i go about using exec() if thats the case.
Also can i run a file like notepad.exe present in system32 by providing the path of notepad.exe as an arguement in exec

i would be really grateful to you if you can write
the syntax for me along eith the class.i tried it out
and i got a lot of errors
this is what i obbtained from the documentation
"public Process exec(String command)
throws IOException"
l to comprehend is what that class Process is doing
in the syntax.from the method its supposed to return
Process class.can you explain it and the usage of
exec too
import java.lang.*;
class abc
Runtime ob1;
ob1.exec("c:\\windows\\system32\\notepad.exe");
//i am getting a compile time error for this code
which cites that <identifier> required at line 6You need to put the exec call in a method or constructor. You can't just place code anywhere within a class.
You should also cal Runtime.exec just as I told you. It's a static method.
There are lots of examples if you google.
Kaj

Problem using repaint() method from another class

I am trying to make tower of hanoi...but unable to transfer rings from a tower to another...i had made three classes....layout21 where all componentents of frame assembled and provided suitable actionlistener.....second is mainPanel which is used to draw the rods n rings in paintComponent.....and third is tower in which code for hanoi is available...i had made an object of mainPanel at layoout21 n tower but i m not able to call repaint from tower..gives an error : cannot find the symbol....method repaint in tower.
code fragments od three classes are:
LAYOUT21
class layout21 extends JFrame implements ActionListener
{ private Vector rod1 = new Vector();
private Vector rod2 = new Vector();
private Vector rod3 = new Vector();
private String elem; //comment
public String r22;
public boolean in=false;
public int count=0; //no of times the transfer to other rods performed
private int r3,rings; // current no of rings
private JComboBox nor,col;
private JLabel no;
private JLabel moved;
private JLabel no1;
private JButton start;
private JButton ref;
private AboutDialog dialog;
private JMenuItem aboutItem;
private JMenuItem exitItem;
private tower t;
final mainPanel2 p =new mainPanel2();
public layout21()
{ t = new tower();
     Toolkit kit =Toolkit.getDefaultToolkit();
Image img = kit.getImage("java.gif");
setIconImage(img);
setTitle("Tower Of Hanoi");
setSize(615,615);
setResizable(false);
setBackground(Color.CYAN);
     JMenuBar mbar = new JMenuBar();
setJMenuBar(mbar);
JMenu fileMenu = new JMenu("File");
mbar.add(fileMenu);
aboutItem = new JMenuItem("About");
aboutItem.addActionListener(this);
fileMenu.add(aboutItem);
exitItem = new JMenuItem("Exit");
exitItem.addActionListener(this);
fileMenu.add(exitItem);
Container contentPane =getContentPane();
JPanel bspanel = new JPanel();
JPanel bnpanel = new JPanel();
setBackground(Color.CYAN);
     //JComboBox
nor = new JComboBox();
nor.setEditable(false);
nor.addItem("3");
nor.addItem("4");
nor.addItem("5");
nor.addItem("6");
nor.addItem("7");
nor.addItem("8");
nor.addItem("9");
bspanel.add(nor);
col = new JComboBox();
col.setEditable(false);
col.addItem("BLACK");
col.addItem("GREEN");
col.addItem("CYAN");
bspanel.add(col);
JLabel tl = new JLabel("Time");
tl.setFont(new Font("Serif",Font.BOLD,12));
bspanel.add(tl);
JTextField tlag = new JTextField("0",4);
bspanel.add(tlag);
start =new JButton("Start");
bspanel.add(start);
ref =new JButton("Refresh");
bspanel.add(ref);
JButton end =new JButton("End");
bspanel.add(end);
start.addActionListener(this);
nor.addActionListener(this);
col.addActionListener(this);
ref.addActionListener(this);
end.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
dispose(); // Closes the dialog
contentPane.add(bspanel,BorderLayout.SOUTH);
JLabel count = new JLabel("No of Transfer reguired:");
count.setFont(new Font("Serif",Font.BOLD,16));
bnpanel.add(count);
no = new JLabel("7");
no.setFont(new Font("Serif",Font.BOLD,16));
bnpanel.add(no);
JLabel moved = new JLabel("Moved:");
moved.setFont(new Font("Serif",Font.BOLD,16));
bnpanel.add(moved);
no1 = new JLabel("0");
no1.setFont(new Font("Serif",Font.BOLD,16));
bnpanel.add(no1);
contentPane.add(bnpanel,BorderLayout.NORTH);
contentPane.add(p,BorderLayout.CENTER);
     String r = (String)nor.getSelectedItem();
rings = Integer.valueOf(r).intValue();
p.draw(rings,1) ;
public void actionPerformed(ActionEvent evt)
{ Object source = evt.getSource();
if(source == start)
r3 = Integer.valueOf((String)nor.getSelectedItem()).intValue();
p.transfer(false);
t.initialise(rod1,rod2,rod3,0);
t.towerOfHanoi(r3);
     //repaint();
     if(source == ref)
{ rod1.removeAllElements() ;
rod2.removeAllElements() ;
rod3.removeAllElements() ;
count=0;
          r3 = Integer.valueOf((String)nor.getSelectedItem()).intValue();
          p.draw(r3,1);
p.transfer(true);
no1.setText(""+0);
p.trans_vec(rod1,rod2,rod3);
t.initialise(rod1,rod2,rod3,0);
          System.out.println("");
          repaint();
if(source == nor)
{ JComboBox j = (JComboBox)source;
String item = (String)j.getSelectedItem();
int ring1 = Integer.valueOf(item).intValue();
int a=1;
for(int i=1;i<=ring1;i++)
{ a = a*2;
a=a-1;
no.setText(""+a);
p.draw(ring1,1);
repaint();
if(source == aboutItem)
{ if (dialog == null) // first time
dialog = new AboutDialog(this);
dialog.setVisible(true);
if(source == exitItem)
{ System.exit(0);
     if (source==col)
     { JComboBox j = (JComboBox)source;
String item = (String)j.getSelectedItem();
          repaint();
TOWER
class tower extends Thread
{ private Vector rod1 = new Vector();
private Vector rod2 = new Vector();
private Vector rod3 = new Vector();
private int count ;
private String elem;
final mainPanel2 z =new mainPanel2();
public void initialise(Vector r1,Vector r2,Vector r3,int c)
{ rod1 = r1;
rod2 = r2;
     rod3 = r3;
     count =c;
public void towerOfHanoi(int rings)
for(int i=0;i<rings;i++)
rod1.add(" "+(i+1));
System.out.println("rod1:"+rod1.toString());
hanoi(rings,1,2);
public void hanoi(int m,int i, int j)
if(m>0)
{ hanoi(m-1,i,6-i-j);
if(i==1 && j==2 && rod1.isEmpty()==false)
{ count++;
//no1.setText(""+count);
elem = (String)rod1.remove(0);
rod2.add(0,elem);
     //z.trans_vec(rod1,rod2,rod3);
repaint(); //NOT ABLE TO USE METHOD HERE...WHY??
//z.hanoi_paint();
try
          this.sleep(2000);
          catch (Exception e) { e.printStackTrace() ; }
System.out.println(count+". ROD 2:"+rod2.toString());
if(i==1 && j==3 && rod1.isEmpty()==false)
{ count++;
     //no1.setText(""+count);
     elem = (String)rod1.remove(0);
rod3.add(0,elem);
//z.trans_vec(rod1,rod2,rod3);
repaint();//
// z.hanoi_paint();
               try
          this.sleep(2000);
          catch (Exception e) { e.printStackTrace() ; }
System.out.println(count+". ROD 3:"+rod3.toString());
if(i==2 && j==1 && rod2.isEmpty()==false)
{ count++;
     //no1.setText(""+count);
     elem = (String)rod2.remove(0);
rod1.add(0,elem);
//z.trans_vec(rod1,rod2,rod3);
repaint();
//z.hanoi_paint();
try
          this.sleep(2000);
          catch (Exception e) { e.printStackTrace() ; }
System.out.println(count+". ROD 1:"+rod1.toString());
if(i==2 && j==3 && rod2.isEmpty()==false)
{ count++;
     //no1.setText(""+count);
     elem = (String)rod2.remove(0);
rod3.add(0,elem);
//z.trans_vec(rod1,rod2,rod3);
repaint();
//z.hanoi_paint();
try
          this.sleep(2000);
          catch (Exception e) { e.printStackTrace() ; }
System.out.println(count+". ROD 3:"+rod3.toString());
if(i==3 && j==1 && rod3.isEmpty()==false)
{ count++;
     //no1.setText(""+count);
elem = (String)rod3.remove(0);
rod1.add(0,elem);
//z.trans_vec(rod1,rod2,rod3);
repaint();
//z.hanoi_paint();
     try
          this.sleep(2000);
          catch (Exception e) { e.printStackTrace() ; }
System.out.println(count+". ROD 1:"+rod1.toString());
if(i==3 && j==2 && rod3.isEmpty()==false)
{ count++;
     //no1.setText(""+count);
elem = (String)rod3.remove(0);
rod2.add(0,elem);
//z.trans_vec(rod1,rod2,rod3);
repaint();
//z.hanoi_paint();
try
          this.sleep(2000);
          catch (Exception e) { e.printStackTrace() ; }
System.out.println(count+". ROD 2:"+rod2.toString());
hanoi(m-1,6-i-j,j);
MAINPANEL
class mainPanel2 extends JPanel //throws IOException
public Vector line = new Vector();
public Vector rod11= new Vector();
public Vector rod22= new Vector();
public Vector rod33= new Vector();
public int no_ring;
public int rod_no;
String pixel;
StringTokenizer st,st1;
int x,y;
public boolean initial =true;
public void paintComponent(Graphics g)
{ System.out.println("repaint test");
bresenham(100,60,100,360);
     bresenham(101,60,101,360);
bresenham(102,60,102,360);
bresenham(103,60,103,360);
bresenham(104,60,104,360);
g.setColor(Color.BLUE);
while(line.size()>0)
{ pixel = (String)line.remove(0);
st = new StringTokenizer(pixel);
x = Integer.valueOf(st.nextToken()).intValue();
y = Integer.valueOf(st.nextToken()).intValue();
g.drawLine(x,y,x,y);
bresenham(300,60,300,360);
bresenham(301,60,301,360);
bresenham(302,60,302,360);
bresenham(303,60,303,360);
bresenham(304,60,304,360);
while(line.size()>0)
{ pixel = (String)line.remove(0);
st = new StringTokenizer(pixel);
x = Integer.valueOf(st.nextToken()).intValue();
y = Integer.valueOf(st.nextToken()).intValue();
g.drawLine(x,y,x,y);
bresenham(500,60,500,360);
bresenham(501,60,501,360);
bresenham(502,60,502,360);
bresenham(503,60,503,360);
bresenham(504,60,504,360);
while(line.size()>0)
{ pixel = (String)line.remove(0);
st = new StringTokenizer(pixel);
x = Integer.valueOf(st.nextToken()).intValue();
y = Integer.valueOf(st.nextToken()).intValue();
g.drawLine(x,y,x,y);
bresenham(0,361,615,361);//used to get a pixel according to algo.. . func not provided
bresenham(0,362,615,362);
bresenham(0,363,615,363);
bresenham(0,364,615,364);
bresenham(0,365,615,365);
while(line.size()>0)
{ pixel = (String)line.remove(0);
st = new StringTokenizer(pixel);
x = Integer.valueOf(st.nextToken()).intValue();
y = Integer.valueOf(st.nextToken()).intValue();
g.drawLine(x,y,x,y);
if(initial==true)
g.setColor(Color.RED);
for(int i = no_ring;i>0;i--)
{ g.drawLine(100-(i*8),360-(no_ring - i)*10,100+(i*8)+5,360-(no_ring - i)*10);
g.drawLine(100-(i*8),359-(no_ring - i)*10,100+(i*8)+5,359-(no_ring - i)*10);
g.drawLine(100-(i*8),358-(no_ring - i)*10,100+(i*8)+5,358-(no_ring - i)*10);
g.drawLine(100-(i*8),357-(no_ring - i)*10,100+(i*8)+5,357-(no_ring - i)*10);
g.drawLine(100-(i*8),356-(no_ring - i)*10,100+(i*8)+5,356-(no_ring - i)*10);
// draw for each rod
//System.out.println("rod11:"+rod11);
//System.out.println("rod22:"+rod22);
//System.out.println("rod33:"+rod33);
     int r1 = rod11.size();
     int r2 = rod22.size();
     int r3 = rod33.size();
String rd1,rd2,rd3;
int r11,r12,r21,r22,r31,r32;
if(initial == false)
     { g.setColor(Color.RED);
     while(rod11.size()>0)
{ r12 = rod11.size()-1;
          rd1 = (String)rod11.remove(r12);
r11 = Integer.valueOf(rd1).intValue();
g.drawLine(100-((r11+1)*8),360-(r1 - (r11+1))*10,100+((r11+1)*8)+5,360-(r1 - (r11+1))*10);
g.drawLine(100-((r11+1)*8),359-(r1 - (r11+1))*10,100+((r11+1)*8)+5,359-(r1 - (r11+1))*10);
          g.drawLine(100-((r11+1)*8),358-(r1 - (r11+1))*10,100+((r11+1)*8)+5,358-(r1 - (r11+1))*10);
          g.drawLine(100-((r11+1)*8),357-(r1 - (r11+1))*10,100+((r11+1)*8)+5,357-(r1 - (r11+1))*10);
          g.drawLine(100-((r11+1)*8),356-(r1 - (r11+1))*10,100+((r11+1)*8)+5,356-(r1 - (r11+1))*10);
     while(rod22.size()>0)
{ g.setColor(Color.RED);
          r22 = rod22.size()-1;
     System.out.println("TEST *************************:"+r22);
          try
     // e.printStackTrace();
          InputStreamReader isr = new InputStreamReader(System.in);
     BufferedReader br = new BufferedReader(isr)      ;
     br.readLine() ;
     }catch(Exception f) {}
          rd2 = ((String)rod22.remove(r22)).trim();
r21 = Integer.valueOf(rd2).intValue();
g.drawLine(300-((r22+1)*8),360-(r2 - (r22+1))*10,300+((r22+1)*8)+5,360-(r2 - (r22+1))*10);
g.drawLine(300-((r22+1)*8),359-(r2 - (r22+1))*10,300+((r22+1)*8)+5,359-(r2 - (r22+1))*10);
          g.drawLine(300-((r22+1)*8),358-(r2 - (r22+1))*10,300+((r22+1)*8)+5,358-(r2 - (r22+1))*10);
          g.drawLine(300-((r22+1)*8),357-(r2 - (r22+1))*10,300+((r22+1)*8)+5,357-(r2 - (r22+1))*10);
          g.drawLine(300-((r22+1)*8),356-(r2 - (r22+1))*10,300+((r22+1)*8)+5,356-(r2 - (r22+1))*10);
     while(rod33.size()>0)
{ g.setColor(Color.RED);
          r32 = rod33.size()-1;
          rd3 = (String)rod33.remove(r32);
r31 = Integer.valueOf(rd3).intValue();
g.drawLine(500-((r32+1)*8),360-(r3 - (r32+1))*10,500+((r32+1)*8)+5,360-(r3 - (r32+1))*10);
g.drawLine(500-((r32+1)*8),359-(r3 - (r32+1))*10,500+((r32+1)*8)+5,359-(r3 - (r32+1))*10);
          g.drawLine(500-((r32+1)*8),358-(r3 - (r32+1))*10,500+((r32+1)*8)+5,358-(r3 - (r32+1))*10);
          g.drawLine(500-((r32+1)*8),357-(r3 - (r32+1))*10,500+((r32+1)*8)+5,357-(r3 - (r32+1))*10);
          g.drawLine(500-((r32+1)*8),356-(r3 - (r32+1))*10,500+((r32+1)*8)+5,356-(r3 - (r32+1))*10);
why i m not able to use repaint() method in tower class? from where i can use repaint() method

i can't read your code - not formatted with code tags
I have no chance of getting it to compile (AboutDialog class?? p.draw() ??)
here's a basic routine - add a couple of things to this to demonstrate what is not
being redrawn
(compare the readability of below code (using tags) to yours)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Testing extends JFrame
public Testing()
    setSize(400,300);
    setLocation(400,300);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    final DrawPanel dp = new DrawPanel();
    JButton btn = new JButton("Change Text Location/Repaint");
    getContentPane().add(dp,BorderLayout.CENTER);
    getContentPane().add(btn,BorderLayout.SOUTH);
    btn.addActionListener(new ActionListener(){
      public void actionPerformed(ActionEvent ae){
        dp.x = (int)(Math.random()*300);
        dp.y = (int)(Math.random()*150)+50;
        repaint();}});
public static void main(String[] args){new Testing().setVisible(true);}
class DrawPanel extends JPanel
int x = 50, y = 50;
public void paintComponent(Graphics g)
    super.paintComponent(g);
    g.drawString("Hello World",x,y);
}

Use a method from another class in another package?

Similar Messages

Maybe you are looking for