Help required: Using objects/methods in other classes

Hi
Say you have a class that has a private string instance variable and you have a accessor and mutator method for this object in that class.
You have another class that needs to access this object via the accessor and mutator methods. How do you do this? When I try I only get nullPointerExceptions or Stack Overflows!!! If anyone can provide some code on how to do this successfully then that will be most appreciated. Thanks.

Kayaman gave you the right answer
public class MyDataClass {
private String importantString;
public void setImpString(String s) {
importantString = s;
public String getImpString() {
return importantString;
public class MyMainClass {
public static void main(String[] args) {
MyDataClass a = new MyDataClass();
a.setImpString("This is important");
System.out.println(a.getImpString());
}Note that he sets the value of the imp string before trying to get it. The nullpointer that you say is probably because you dont do that.
Also When you aks a question a little humility doesnt hurt.
You do need a tutorial first.

Similar Messages

Can I use object methods in a class

I have a class ball and I am in the process of creating it's move method. I want this method to make the ball move depending on certain factors.
One of these factors being where a bar has been stopped. I have a bar class which extends JProgressBar and when stopped, produces a number. I want this number to be available to my ball class in some way so it can use it to determine how far the ball has to move. The number can be output using its method getValue() but I am unsure how this can be used by another class.
I doubt this is possible, but I am sure there are ways to achieve what I want. Any help on this subject would be great.

Methods in one class can call methods defined in another class, subject to access restrictions (public, protected, package-private). This is pretty basic, so you should be able to get the meat of it from your text or tutorial. Look there, or in the following for explanations and examples, and post again if you can't get your code to work.
http://java.sun.com/docs/books/tutorial/
http://java.sun.com/learning/new2java/index.html
http://javaalmanac.com
http://www.jguru.com
http://www.javaranch.com
Bruce Eckel's Thinking in Java
Joshua Bloch's Effective Java
Bert Bates and Kathy Sierra's Head First Java

Use methods in other classes

Can I use methods from other classes than the class that myClass extends?
ex. myClass extends parentClass{
myMethod()
myMethod() is declared in i third class. Is this possible or can I only use classes from the parent class?
-Thanks-

I'm not really sure what the previous two answers were getting at.
Yes, you can use methods all the way up the class hierarchy, as long as they are visible.
For example, Object implements toString(). You can call toString() on any object in Java and it will render the object to a string in one way or another. That is because toString() is public.
If toString() were protected, you would only be able to call the method if you were a subclass of of that object (or in the same package), which would make the toString() method much less useful.
I would suggest reading up on the differences in the four visibility modifiers (private, (default), protected, and public). Private is the only one which nothing else can call. If you are public or protected, any subclass can call the method, even if there are 20 superclasses between the implementor and the caller.
Good luck!
Steve

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?

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?

Creating user view using 'createView' method of RemoteSession class

Hi
I am trying to create a user view using createView method of RemoteSesson class.
the code is as follows:
remoteSession = (RemoteSession)SessionFactory.getSession(REMOTE_HOST, ADMIN_ID, encryptedPassword);
HashMap map = new HashMap();
map.put("type", "User");
map.put("viewId", "User");
GenericObject obj =
remoteSession.createView("#ID#3DA2A7588B5510DC:-4D08423:10AAD335A14:-7FEE", map);
I get the following error on the server side:
WavesetException: Missing object type
com.waveset.util.WavesetException: Missing object type
     at com.waveset.util.WavesetException.checkBreakpoint(WavesetException.java:366)
     at com.waveset.util.WavesetException.<init>(WavesetException.java:133)
     at com.waveset.rpc.GenericMessageHandler.createView(Unknown Source)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:585)
     at com.waveset.rpc.GenericMessageHandler.request(Unknown Source)
     at com.waveset.rpc.SimpleRpcHandler.doRequest(SimpleRpcHandler.java:164)
     at com.waveset.rpc.SimpleRpcHandler.doRequest(SimpleRpcHandler.java:128)
     at org.openspml.server.SOAPRouter.doPost(SOAPRouter.java:500)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
     at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
     at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
     at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
     at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
     at java.lang.Thread.run(Thread.java:595)
Could anyone tell me what is wrong with this code?
Thanks!

hi carlos,
yes it is possible. as a reference please have a look at this document How to Reference External JAR Files in Web Dynpro DC in SAP NW Portal 7.3
basically the steps are the same (adding dependency, public parts, etc.) for a ejb or java project.
regards,
christian

Forbit use of method forName of Class

I have some JAVA applications running in iPlanet Application Server (iAS). I need that the connection to database was only by the pool of iAS and nobody can use:
Class.forName("oracle.jdbc.driver.OracleDriver"); to connect to DB.
How can forbit use of method forName of Class?

You can't.

Help me, calling a method in another class.

public class xxx extends thread{
User aUser=new User("MARY") //create an object in the User class
aUser.SendToOnlineList(); // i want to use the SendToOnlineList() method to call the AddToList() method which is in the OnlineList class
OnlineList.ReturnList();   // and then i want to get back the online list by using the method ReturnList() in the class OnlineList.
class User {
      private final String userId;
    public User(String userId) { //constructor
        this.userId = userId;
public void SendToOnlineList () {
    OnlineList.ServerOnlineList.AddToList(this); // netbeans underlines this statement!!!!!!!!can anybody help me with codes?
class OnlineList {
   ArrayList ServerOnlineList=new ArrayList();
   public void AddToList(User user) {
       ServerOnlineList.add(user); // I want to add a User object into the ServerOnlineList( this is an arraylist) in this class
public ArrayList ReturnList () {
return ServerOnlineList;
}can you help me???thanks!!!!!!!!!!!!!!

@OP: You need to stop this.
You don't grasp even the basics of Java, and you're trying to write a client/server app. That is not reasonable. If you don't understand how to initialize a variable or how to print things out or what public means, or how to debug your own NullPointerExceptions, or any of a host of other basics that seem to stump you, then you're in way over your head.
It doesn't matter if you "have to" do this because it's an assignment for school. Posting a new thread here for each of the 80 bazillion things you don't undertsand will not help you to learn, and it's getting very annoying.
If you really want to learn Java, then go through one of more of the following.
Sun's basic Java tutorial
Sun's New To Java Center. Includes an overview of what Java is, instructions for setting up Java, an intro to programming (that includes links to the above tutorial or to parts of it), quizzes, a list of resources, and info on certification and courses.
http://javaalmanac.com. A couple dozen code examples that supplement The Java Developers Almanac.
jGuru. A general Java resource site. Includes FAQs, forums, courses, more.
JavaRanch. To quote the tagline on their homepage: "a friendly place for Java greenhorns." FAQs, forums (moderated, I believe), sample code, all kinds of goodies for newbies. From what I've heard, they live up to the "friendly" claim.
Bruce Eckel's Thinking in Java (Available online.)
Joshua Bloch's Effective Java
Bert Bates and Kathy Sierra's Head First Java.

How to use protected method of a class in application

Hi,
will u please tell me how to use protected method of class in application. (class:cl_gui_textcontrol, method:limit_text)
Thanks in advance,
Praba.

Hi Prabha,
You can set the maximum number of characters in a textedit control in the CREATE OBJECT statement itself.
Just see the first parameter in the method . I mean MAX_NUMBER_CHARS. Just set that value to the required number.
Eg:
data: edit type ref to CL_GUI_TEXTEDIT.
create object edit
exporting
    MAX_NUMBER_CHARS       = 10
   STYLE                  = 0
   WORDWRAP_MODE          = WORDWRAP_AT_WINDOWBORDER
   WORDWRAP_POSITION      = -1
   WORDWRAP_TO_LINEBREAK_MODE = FALSE
   FILEDROP_MODE          = DROPFILE_EVENT_OFF
    parent                 = OBJ_CUSTOM_CONTAINER
   LIFETIME               =
   NAME                   =
EXCEPTIONS
    ERROR_CNTL_CREATE      = 1
    ERROR_CNTL_INIT        = 2
    ERROR_CNTL_LINK        = 3
    ERROR_DP_CREATE        = 4
    GUI_TYPE_NOT_SUPPORTED = 5
    others                 = 6
IF sy-subrc <> 0.
MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
           WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
In this case, the max: number of characters will be set to 10.
I hope your query is solved.
Regards,
SP.

PowerShell-EWS How to use .Forward Method of EmailMessage Class

Hello,
im new to PowerShell and EWS and would like to know how to forward an E-Mail with the .Forward Method of the EmailMessage Class.
Is it possible to also forward an Email with an FileAttachment?
I already have access to the Messages i want to forward but i cant figure out how to .Forward these Messages.
Thank you for your help
Greetings
Ingo

>> Is it possible to also forward an Email with an FileAttachment?
Yes doing a normal forward is EWS should maintain the attachment on the message eg the following would forward the last email in the Mailbox
$folderid= new-object Microsoft.Exchange.WebServices.Data.FolderId([Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Inbox,$MailboxName)
$Inbox = [Microsoft.Exchange.WebServices.Data.Folder]::Bind($service,$folderid)
$ivItemView = New-Object Microsoft.Exchange.WebServices.Data.ItemView(1)
$fiItems = $null
$fiItems = $service.FindItems($Inbox.Id,$ivItemView)
$messageBodyPrefix = "This is message that was forwarded by using the EWS Managed API";
$addresses = New-Object Microsoft.Exchange.WebServices.Data.EmailAddress[] 1
$addresses[0] = "[email protected]";
$fiItems.Items[0].Forward($messageBodyPrefix, $addresses);
If your looking to forward the actual message as an attachment you can use something like
http://gsexdev.blogspot.com.au/2013/07/forwarding-message-as-attachment-using.html
Cheers
Glen

Making object accesible from other class?

hi all
how can i have an object of class to be accesible from other class?
thanks

It's not clear what you mean by "object of class". Do you mean fields within an object. Do you mean using an object of one class within the code of another?
For most named objectes in java, whether field, method or class, there are four levels of access.
public means accessible from anywhere in the program
private means accessible only from the same source file.
protected means only from the class, or a class that extends it.
or if you don't put any of these keywords it means accessible only from the same package, that is set of source files in a single directory.

NEED HELP WITH USING STATIC METHOD - PLEASE RESPOND ASAP!

I am trying to set a value on a class using a static method. I have defined a servlet attribute (let's call it myAttribute) on my webserver. I have a serlvet (let's call it myServlet) that has an init() method. I have modified this init() method to retrieve the attribute value (myAttribute). I need to make this attribute value accessible in another class (let's call it myOtherClass), so my question revolves around not knowing how to set this attribute value on my other class using a static method (let's call it setMyStuff()). I want to be able to make a call to the static method setMyStuff() with the value of my servlet attribute. I dont know enough about static member variables and methods. I need to know what to do in my init() method. I need to know what else I need to do in myServlet and also what all I need in the other class as well. I feel like a lot of my problems revolve around not knowing the proper syntax as well.
Please reply soon!!! Thanks in advance.

class a
private static String aa = "";
public static setVar (String var)
aa = var;
class b
public void init()
a.aa = "try";
public static void main(String b[])
b myB = new b ();
b.init();
hope this help;
bye _drag

Using a method of a class within an action event

Good day.
A beginner question.
It is possible to use within an action event (triggered by a view of the button)
instantiate a class from another java project and use a method?
If it is possible how to do?
Thank you

hi carlos,
yes it is possible. as a reference please have a look at this document How to Reference External JAR Files in Web Dynpro DC in SAP NW Portal 7.3
basically the steps are the same (adding dependency, public parts, etc.) for a ejb or java project.
regards,
christian

JFrame not showing components when called method in other class

Hi everyone,
I am new to SWING,and have this little problem.
i have created a JFrame which has a button and its calling a method in another class.the result takes much more time(around 3mins) as the call involved with FTP.
My problem is , i click the button(other componetns also there),and waiting for the result.all the time my Frame doesnt show any of the components,it looks as if the components are added to it.but when the call returns.everything is OK.
Can any1 help me?
Thanx in advance
ethirajan

http://java.sun.com/docs/books/tutorial/essential/threads/
http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html
http://java.sun.com/products/jfc/tsc/articles/threads/threads1.html

Calling methods from other classes

I have a bunch of little java files in a folder, do I need to make a package in order to access all the methods in all the classes, or can I just make an instance of any of the methods because all the classes are in the same folder?

HI,
If your methods have a "public" modifier (and the class does too) then you can instantiate your classes as objects from that (so-called) "default" package in any other class or object in any other package and then call the methods on those instantiated objects as you please.
If that sounds confusing... I'd seriously try the excellent tutorials at this site, especially "the java tutorial".
/k1

Help required: Using objects/methods in other classes

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