Using swing on j#

i konw there have been programs to use swing on j++, but how about on its upgrade, j#? anyone know if there is a way or there is something in the makes or if there is any way to take the javax package and put it into the j# program file any solutions please let me know

To be sure, M$ Visual Studio is an excellent IDE (although it has its share of bugs). Perhaps even one of the best out there.But you are confusing the language with the IDE. They ain't the same.
Java != J++ and Java != J# . The syntax is Java-like, but with additional microsoft extensions, and lacking support for Java facilities such as JNI and RMI.
IMHO, there's no point in using J#, unless you have a J++ application that you want to port over. If you want to use .net and M$, you may as well use C# - it's a much cleaner break with Java, and consequently contains some niceties that weren't possible with the Java syntax.

Similar Messages

Can't use Swing in my java application

I installed J2SE 5 Update 4 on my machine and was trying my hands on creating GUI using swing. I kept getting the error message: "Package javax,swing not found in import".
I have the statement: import javax.swing.*; in my code so I don't what to do again.
Thanks

I think your best bet is to try uninstalling and installing Java again. Your problem could be something small, however you wull eaist less time to re-install everything, then to try searching for the problem.
btw-What Development tool do you use? Just in case you may try to check whether it could be a problem of the ide (It should not be however), just check with another Ide, and see if the same happens. If yes, then follow my first advise, I think it would take you less time.

I can't use swing components in my applets

When I write an applet without any swing components, my browser never has any trouble finding the classes it needs, whether they're classes I've written or classes that came with Java. However, when I try to use swing components it cannot find them, because it is looking in the wrong place:
On my computer I have a directory called C:\Java, into which I installed my Java Development Kit (so Sun's classes are stored in the default location within that directory, wherever that is), and I store my classes in C:\Java\Files\[path depends on package]. My browser gives an error message along the lines of "Cannot find class JFrame at C:\Java\Files\javax\swing\JFrame.class"; it shouldn't be looking for this non-existent directory, it should find the swing components where it finds, for example, the Applet class and the Graphics class.
Is there any way I can set the classpath on my browser? Are the swing components stored separately from other classes (I'm using the J2SE v1.3)?
Thanks in advance.

Without having complete information, it appears that you are running your applets using the browser's VM. Further, I assume you are using either IE or Netscape Navigator pre-v6. In that case, your browser only supports Java 1.1, and Swing was implemented in Java 1.2. You need to use the Java plug-in in order to use the Swing classes (see the Plug-in forum for more information), or else download the Swing classes from Sun and include them in your CLASSPATH.
HTH,
Carl Rapson

Using Swing as interface to a dll

I am trying to use Swing as my cross platform GUI for c++ dll's. Each dll has its own GUI. However, one of my dll's controls what other dlls are loaded. This works fine until I try to load a second instance of the control dll. I get an access violation message when I try to update my gui. If I try to load the two dlls from the c++ everything works fine, but if I load one from the Java GUI I get an null access exception. I'm guessing its caused by one of two problems:
1) The DLL loading is trashing the executing stack of either the JAVA or the native code.
2) As the code returns from the constructor call to the newly loaded dll JNI is deleting the interface objects that it is creating on the heap.
Any ideas would be greatly appreciated.
Unfortunately I don't get an error log from JAVA.
VisualStudio gives me:
Unhandled exception at 0x10014a7d (nativedll.dll) in testjava.exe: 0xC0000005: Access violation reading location 0xfeeefef6.
The print out reads:
Creating Java VM
No. Created VMs 0
Creating Frame
Created frame
Begin master update loop
Calling Update
Updated Frame 0
Creating Java VM
No. Created VMs 1
Creating Frame
Created frame
Calling Update
I am using Visual Studio .Net 2003 and jdk 1.4.4, 1.5.0_08 and 1.6.0.
Main application:
#include "Windows.h"
#include "nativelibrary.h"
#include <stdlib.h>
#include <string.h>
#include "jni.h"
int main(int argc, char* argv[])
       //Load first library
     HMODULE handle = LoadLibrary( "../../nativedll/debug/nativedll.dll");
     nativelibrary* (*funcPtr)();
     funcPtr = (nativelibrary*(*)())GetProcAddress( handle, "createObj");
     nativelibrary* newObj = (*funcPtr)();
        // update each library
     for (int i = 0; i < 10000; i++)
          printf ("Begin master update loop\n");
          void (*funcPtr2)();
          funcPtr2 = (void(*)())GetProcAddress( handle, "update");
          (*funcPtr2)();
          printf ("End master update loop\n");
          Sleep(10);
     // Sleep(100000);
     return 0;
}Main Library
#include <iostream>
#include "jni.h"
#include "MyFrame.h"
#include "StaticFunc.h"
#include <stdlib.h>
#include <vector>
#include "Windows.h"
using namespace std;
class nativelibrary
public:
     JavaVM *jvm;
     JNIEnv *env;
     jclass cls;
     jobject myFrame;
     nativelibrary();
     void locupdate();
     static vector<nativelibrary*> objects;
vector<nativelibrary*> nativelibrary::objects;
nativelibrary* createObj()
     return new nativelibrary();
nativelibrary::nativelibrary()
     // JavaVMOption options[0];
     JavaVMInitArgs vm_args;
     memset(&vm_args, 0, sizeof(vm_args));
     vm_args.version = JNI_VERSION_1_4;
     vm_args.nOptions = 0;
     vm_args.ignoreUnrecognized = true;
     vm_args.nOptions = 0;
     // vm_args.options = options;
     JavaVM** jvmBuf = (JavaVM**)malloc(sizeof(JavaVM*));
     jsize buflen = 1;
     jsize nVMs =0;
     // vm_args.options[0].optionString = "-Djava.class.path=../../bin/Debug";
     // Create the Java VM
     printf("Creating Java VM\n");
     jint res = JNI_GetCreatedJavaVMs(jvmBuf, buflen, &nVMs);
     if ( res >= 0)
          printf("No. Created VMs %i\n", nVMs);
          if ( nVMs > 0)
               jvm = jvmBuf[0];
               res = jvm->GetEnv((void**)&env,vm_args.version);
          else
               res = JNI_CreateJavaVM(&jvm,(void**)&env,&vm_args);
     else
          res = JNI_CreateJavaVM(&jvm,(void**)&env,&vm_args);
     cls = env->FindClass("LMyFrame;");
     if ( cls == 0 ) printf("Cannot find MyFrame");
     jmethodID mid = env->GetMethodID(cls, "<init>", "()V");
     if ( mid == 0 ) printf("Cannot find constructor");
     printf("Creating Frame\n");
     myFrame = env->NewObject(cls, mid);
     if (env->ExceptionOccurred())
          env->ExceptionDescribe();
     printf("Created frame\n");
     objects.push_back(this);
void nativelibrary::locupdate()
     printf("Calling Update\n");
     jmethodID updatemid = env->GetMethodID(cls, "update", "()V");
     if ( updatemid == 0 ) printf("Cannot find update");
     env->CallVoidMethod(myFrame, updatemid);
     if (env->ExceptionOccurred())
          env->ExceptionDescribe();
void update()
     vector<nativelibrary*>::iterator it = nativelibrary::objects.begin();
     while (it != nativelibrary::objects.end())
          nativelibrary* lib = *it;
          lib->locupdate();
          it++;
JNIEXPORT void JNICALL Java_MyFrame__1createObj
(JNIEnv *, jclass)
     createObj();
}Java Class (User interface)
class MyFrame
     static native void _createObj();
     static int creations = 0;
     int framenum;
     MyFrame()
          System.loadLibrary("../../nativedll/Debug/nativedll");
          framenum = creations++;
     void update()
          System.out.println("Updated Frame " + framenum);
          if ( creations == 1)
               // load dll as a result of the user clicking on the interface
               createObj();
     public static void createObj()
          _createObj();
}

I am trying to use Swing as my cross platform GUI for c++ dll's. Each dll has its own GUI. However, one of my dll's controls what other dlls are loaded. This works fine until I try to load a second instance of the control dll. I get an access violation message when I try to update my gui. If I try to load the two dlls from the c++ everything works fine, but if I load one from the Java GUI I get an null access exception. I'm guessing its caused by one of two problems:
1) The DLL loading is trashing the executing stack of either the JAVA or the native code.
2) As the code returns from the constructor call to the newly loaded dll JNI is deleting the interface objects that it is creating on the heap.
Any ideas would be greatly appreciated.
Unfortunately I don't get an error log from JAVA.
VisualStudio gives me:
Unhandled exception at 0x10014a7d (nativedll.dll) in testjava.exe: 0xC0000005: Access violation reading location 0xfeeefef6.
The print out reads:
Creating Java VM
No. Created VMs 0
Creating Frame
Created frame
Begin master update loop
Calling Update
Updated Frame 0
Creating Java VM
No. Created VMs 1
Creating Frame
Created frame
Calling Update
I am using Visual Studio .Net 2003 and jdk 1.4.4, 1.5.0_08 and 1.6.0.
Main application:
#include "Windows.h"
#include "nativelibrary.h"
#include <stdlib.h>
#include <string.h>
#include "jni.h"
int main(int argc, char* argv[])
       //Load first library
     HMODULE handle = LoadLibrary( "../../nativedll/debug/nativedll.dll");
     nativelibrary* (*funcPtr)();
     funcPtr = (nativelibrary*(*)())GetProcAddress( handle, "createObj");
     nativelibrary* newObj = (*funcPtr)();
        // update each library
     for (int i = 0; i < 10000; i++)
          printf ("Begin master update loop\n");
          void (*funcPtr2)();
          funcPtr2 = (void(*)())GetProcAddress( handle, "update");
          (*funcPtr2)();
          printf ("End master update loop\n");
          Sleep(10);
     // Sleep(100000);
     return 0;
}Main Library
#include <iostream>
#include "jni.h"
#include "MyFrame.h"
#include "StaticFunc.h"
#include <stdlib.h>
#include <vector>
#include "Windows.h"
using namespace std;
class nativelibrary
public:
     JavaVM *jvm;
     JNIEnv *env;
     jclass cls;
     jobject myFrame;
     nativelibrary();
     void locupdate();
     static vector<nativelibrary*> objects;
vector<nativelibrary*> nativelibrary::objects;
nativelibrary* createObj()
     return new nativelibrary();
nativelibrary::nativelibrary()
     // JavaVMOption options[0];
     JavaVMInitArgs vm_args;
     memset(&vm_args, 0, sizeof(vm_args));
     vm_args.version = JNI_VERSION_1_4;
     vm_args.nOptions = 0;
     vm_args.ignoreUnrecognized = true;
     vm_args.nOptions = 0;
     // vm_args.options = options;
     JavaVM** jvmBuf = (JavaVM**)malloc(sizeof(JavaVM*));
     jsize buflen = 1;
     jsize nVMs =0;
     // vm_args.options[0].optionString = "-Djava.class.path=../../bin/Debug";
     // Create the Java VM
     printf("Creating Java VM\n");
     jint res = JNI_GetCreatedJavaVMs(jvmBuf, buflen, &nVMs);
     if ( res >= 0)
          printf("No. Created VMs %i\n", nVMs);
          if ( nVMs > 0)
               jvm = jvmBuf[0];
               res = jvm->GetEnv((void**)&env,vm_args.version);
          else
               res = JNI_CreateJavaVM(&jvm,(void**)&env,&vm_args);
     else
          res = JNI_CreateJavaVM(&jvm,(void**)&env,&vm_args);
     cls = env->FindClass("LMyFrame;");
     if ( cls == 0 ) printf("Cannot find MyFrame");
     jmethodID mid = env->GetMethodID(cls, "<init>", "()V");
     if ( mid == 0 ) printf("Cannot find constructor");
     printf("Creating Frame\n");
     myFrame = env->NewObject(cls, mid);
     if (env->ExceptionOccurred())
          env->ExceptionDescribe();
     printf("Created frame\n");
     objects.push_back(this);
void nativelibrary::locupdate()
     printf("Calling Update\n");
     jmethodID updatemid = env->GetMethodID(cls, "update", "()V");
     if ( updatemid == 0 ) printf("Cannot find update");
     env->CallVoidMethod(myFrame, updatemid);
     if (env->ExceptionOccurred())
          env->ExceptionDescribe();
void update()
     vector<nativelibrary*>::iterator it = nativelibrary::objects.begin();
     while (it != nativelibrary::objects.end())
          nativelibrary* lib = *it;
          lib->locupdate();
          it++;
JNIEXPORT void JNICALL Java_MyFrame__1createObj
(JNIEnv *, jclass)
     createObj();
}Java Class (User interface)
class MyFrame
     static native void _createObj();
     static int creations = 0;
     int framenum;
     MyFrame()
          System.loadLibrary("../../nativedll/Debug/nativedll");
          framenum = creations++;
     void update()
          System.out.println("Updated Frame " + framenum);
          if ( creations == 1)
               // load dll as a result of the user clicking on the interface
               createObj();
     public static void createObj()
          _createObj();
}

How can i connect multiple forms using swings or applets(AWT) & with D-Base

Hello Friends,
I am Sreedhar from Hyderabad. working as a java developer in a small organization. I got a challenge to work on java stand alone (desktop) application. Basically our company is based on SCM(Supply Chain Management), I never work before using swings and AWT. now my present challenge is to develope an application on swings and AWT using Net Beans IDE. but i am unble find the code to connect one form to another form, i want to develop similar application like a web application , suppose if i click on OK button it has to connect next form. in the next for it has to take user name and password should allow me to access main form. please help me about this topic, if anybody interested i can send u the screen shots and i can post to ur mail. please help me as soon as possible,

sreedharkommuru wrote:
Hello Friends,
I am Sreedhar from Hyderabad. working as a java developer in a small organization. I got a challenge to work on java stand alone (desktop) application. Basically our company is based on SCM(Supply Chain Management), I never work before using swings and AWT. now my present challenge is to develope an application on swings and AWT using Net Beans IDE. but i am unble find the code to connect one form to another form, i want to develop similar application like a web application , suppose if i click on OK button it has to connect next form. in the next for it has to take user name and password should allow me to access main form. please help me about this topic, if anybody interested i can send u the screen shots and i can post to ur mail. please help me as soon as possible,There is no magic, you need to spend a good amount of time in tutorials, here is a good one to start off with:
[The Really Big Index|http://java.sun.com/docs/books/tutorial/reallybigindex.html]
Here are a few tips:
1 - Do not mix AWT and SWING: it'll just cause you headaches in the long run that you cannot fix without refactoring to properly not mix the 2 together.
2 - You use JDBC to access the database
3 - You make accessors/constructors to pass parameters that you need from one form to another.
Have fun.

Is it possible to use events for objects that do not use swing or awt

Dear Experts
I want to know if events are possible with plain java objects. A simple class that is capable of firing an event and another simple class that can receive that event. My question is
1. If it is possible - then what is the approach that needs to be taken and would appreciate an example.
2. Is Observer Pattern in java going to help?
To explain further i am doing [Add,Modify,Delete,Traverse] Data tutorial using swing in Net beans. I have a ButtonState Manager class that enables and disables buttons according to a given situation. For example if add is clicked the modify button becomes Save and another becomes Cancel. The other buttons are disabled. What i want is the ButtonStateManager class to do a little further - i.e. if Save is clicked it should report to DBClass that it has to save the current record which was just added. I am foxed how this can be done or what is the right way. Thanks for reading a long message. Appreciate your help.
Best regards

Thanks Kayaman
i guess i am doing something else maybe it is crazy but i need to work further i guess... i cant post the entire code as it is too big but some snippets
public class DatabaseApplication extends javax.swing.JFrame {
    ButtonStateManager bsm;
    /** Creates new form DatabaseApplication */
    public DatabaseApplication() {
        initComponents();
        // ButtonStateManager has a HUGE constructor that takes all the buttons as argument!
        bsm = new ButtonStateManager(
                btnAdd,
                btnModify,
                btnDelete,
                btnQuit,
                btnMoveNext,
                btnMovePrevious,
                btnMoveLast,
                btnMoveFirst );One of the methods in the ButtonStateManager Class is as follows
private void modifyButtonState()
        btnAdd.setText("Save");
        btnModify.setEnabled(false);
        btnDelete.setText("Cancel");
        btnQuit.setEnabled(false);
        ...Finally the Crazy way i was trying to do ... using EXCEPTIONS!
void modifyClicked() throws DBAction
        if(btnModify.getText().equalsIgnoreCase("MODIFY"))
            modifyButtonState();
        else
            throw new DBAction("SaveAddedRecord");
    }And Finally how i was Tackling exceptions....
private void btnAddActionPerformed(java.awt.event.ActionEvent evt) {
      try {
            bsm.addClicked();
        } catch (Exception e1) {
            processDBAction(e1.getMessage());
    private void processDBAction(String msg)
        if(msg.equalsIgnoreCase("SAVEMODIFIEDRECORD"))
            System.err.println(msg);
            bsm.normalButtonState();
        }Edited by: standman on Mar 30, 2011 4:51 PM

What is the best way to use Swing GUIs in an MVC design?

I have a question on how to build an application using swing frames for the UI, but using an MVC architecture. I've checked the rest of the forum, but not found an answer to my question that meets my needs.
My application at this stage presents a login screen to get the userid and password, or to allow the user to choose a new locale. If an Enter action is performed, the userid and password are checked against the DB. If not accepted, the screen is repainted with a "try-again" message. If the Cancel action is performed, the process stops. If a locale action is performed, the screen is repainted with different langauge labels. Once the login process is passed, a front screen (another swing frame) is presented.
Implementation: I am using a session object (Session, represents the user logging in) that calls the Login screen (LoginGUI, a Swing JFrame object with various components). Session uses setters in LoginGUI to set the labels, initial field entries etc, before enabling the screen. From this point, the user will do something with the LoginGUI screen - could be closing the window, entering a mix of userid and password, or maybe specifying a locale. Once the user has taken the action, if required, the session object can use getters to retrieve the userid and password values entered in the fields.
The crux of the problem is 1) how will Session know that an action has been taken on the LoginGUI, and 2) how to tell what action has been taken.
This could be solved by getting LoginGUI to call back to Session, however, I am trying to buid the application with a good separation of business, logic and presentation (i.e MVC, but not using any specific model). Therefore, I do not want LoginGUI to contain any program flow logic - that should all be contained in Session.
I am aware of two possible ways to do this:
1. Make LoginGUI synchronised, so that Session waits for LoginGUI to send a NotifyAll(). LoginGUI could hold a variable indicating what has happened which Session could interrogate.
2. Implement Window Listener on Session so that it gets informed of the Window Close action. For the other two actions I could use a PropertyChangeListener in Session, that is notified when some variable in LoginGUI is changed. This variable could contain the action performed.
Has anyone got any comments on the merits of these methods, or perhaps a better method? This technique seems fundamental to any application that interfaces with end-users, so I would like to find the best way.
Thanks in advance.

Hi,
I tried to avoid putting in specific code as my question was more on design, and I wanted to save people having to trawl through specific code. And if I had any school assignments outstanding they would be about 20 years too late :-). I'm not sure computers more sophisticated than an abacus were around then...
Rather than putting the actual code (which is long and refers to other objects not relevant to the discussion), I have put together two demo classes to illustrate my query. Comments in the code indicate where I have left out non-relevant code.
Sessiondemo has the main class. When run, it creates an instance of LoginGUIdemo, containing a userid field, password field, a ComboBox (which would normally have a list of available locales), an Enter and a Cancel box.
When the Locale combo box is clicked, the LoginGUIdemo.userAction button is changed (using an ActionListener) and a property change is fired to Session (which could then perform some work). The same technique is used to detect Enter events (pressing return in password and userid, or clicking on Enter), and to detect Cancel events (clicking on the cancel button). Instead of putting in business code I have just put in System.out.printlns to print the userAction value.
With this structure, LoginGUIdemo has no business logic, but just alerts Sessiondemo (the class with the business logic).
Do you know any more elegant way to achieve this function? In my original post, I mentioned that I have also achieved this using thread synchronisation (Sessiondemo waits on LoginGUI to issue a NotifyAll() before it can retrieve the LoginGUI values). I can put together demo code if you would like. Can you post any other demo code to demonstrate a better technique?
Cheers,
Alan
Here's Sessiondemo.class
import java.io.*;
import java.awt.event.*;
import java.util.*;
import java.beans.*;
public class Sessiondemo implements PropertyChangeListener {
    private LoginGUIdemo lgui;   // Login screen
    private int localeIndex; // index referring to an array of available Locales
    public Sessiondemo () {
        lgui = new LoginGUIdemo();
        lgui.addPropertyChangeListener(this);
        lgui.show();
    public static void main(String[] args) {
        Sessiondemo sess = new Sessiondemo();
    public void propertyChange(java.beans.PropertyChangeEvent pce) {
        // Get the userAction value from LoginGUI
        String userAction = pce.getNewValue().toString();
        if (userAction == "Cancelled") {
            System.out.println(userAction);
            // close the screen down
            lgui.dispose();
            System.exit(0);
        } else if (userAction == "LocaleChange") {
            System.out.println(userAction);
            // Get the new locale setting from the LoginGUI
            // ...modify LoginGUI labels with new labels from ResourceBundle
lgui.show();
} else if (userAction == "Submitted") {
System.out.println(userAction);
// ...Get the userid and password values from LoginGUIdemo
            // run some business logic to decide whether to show the login screen again
            // or accept the login and present the application frontscreen
}And here's LoginGUIdemo.class
* LoginGUIdemox.java
* Created on 29 November 2002, 18:59
* @author administrator
import java.beans.*;
public class LoginGUIdemo extends javax.swing.JFrame {
    private String userAction;
    private PropertyChangeSupport pcs;
    /** Creates new form LoginGUIdemox */
    // Note that in the full code there are setters and getters to allow access to the
    // components in the screen. For clarity they are not included here
    public LoginGUIdemo() {
        pcs = new PropertyChangeSupport(this);
        userAction = "";
        initComponents();
    public void setUserAction(String s) {
        userAction = s;
        pcs.firePropertyChange("userAction",null,userAction);
    public void addPropertyChangeListener(PropertyChangeListener l) {
        pcs.addPropertyChangeListener(l);
    public void removePropertyChangeListener(PropertyChangeListener l) {
        pcs.removePropertyChangeListener(l);
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
    private void initComponents() {
        jTextField1 = new javax.swing.JTextField();
        jTextField2 = new javax.swing.JTextField();
        jComboBox1 = new javax.swing.JComboBox();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        getContentPane().setLayout(new java.awt.FlowLayout());
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
        jTextField1.setText("userid");
        jTextField1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                EnterActionPerformed(evt);
        getContentPane().add(jTextField1);
        jTextField2.setText("password");
        jTextField2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                EnterActionPerformed(evt);
        getContentPane().add(jTextField2);
        jComboBox1.setToolTipText("Select Locale");
        jComboBox1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                LocaleActionPerformed(evt);
        getContentPane().add(jComboBox1);
        jButton1.setText("Enter");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                EnterActionPerformed(evt);
        getContentPane().add(jButton1);
        jButton2.setText("Cancel");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                CancelActionPerformed(evt);
        getContentPane().add(jButton2);
        pack();
    private void LocaleActionPerformed(java.awt.event.ActionEvent evt) {
        setUserAction("LocaleChange");
    private void CancelActionPerformed(java.awt.event.ActionEvent evt) {
        setUserAction("Cancelled");
    private void EnterActionPerformed(java.awt.event.ActionEvent evt) {
        setUserAction("Submitted");
    /** Exit the Application */
    private void exitForm(java.awt.event.WindowEvent evt) {
        System.exit(0);
     * @param args the command line arguments
    public static void main(String args[]) {
        new LoginGUIdemo().show();
    // Variables declaration - do not modify
    private javax.swing.JTextField jTextField2;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jButton1;
    // End of variables declaration

Help! File in use problem when using Swing app

Hi. I got a program that is pretty much a JFileChooser that prints to standard output the path of the file that I've chosen. If I invoke the DOS command:
java JFileChooserDemo, I will get the following as expected from the program:
"You chose a file named: C:\MyJava\Book.xls".
But if I invoke the following DOS command:
java JFileChooserDemo > output.txt, the file "output.txt" contains the following:
"GetModuleHandleA succeed
LoadLibrary returns baaa0000
You chose a file named: C:\MyJava\Book.xls"
So, if I try to open the file or try to modify "output.txt", I get an error message stating that the file is in use.
What's weird is that, I THINK if I have a program that DOES'NT use Swing or anything GUI-related and prints to standard output with the DOS "> outfile" command, I won't get this problem. So in other words, I can duplicate this problem with a sample Swing application that prints to standard output. Try it yourself.
In my original program, it does have an event handler that closes the JFileChooser and its container and exits the system via "System.exit(0);", but for some reason, something still has "locked" the output.txt file. I even did the ctr+alt+del and can't find anything that would lock the output.txt file. What's even weirder is that if I run the application again, but output to a different file like "output2.txt", this file is not locked, but the "output.txt" file still is. output2.txt also don't have contain the
"GetModuleHandleA succeed
LoadLibrary returns baaa0000" message.
The only way I know of that would "unlock" output.txt is to re-boot my computer.
So it seems I have to modify my program somehow because it appears the OS still thinks output.txt file is still in use.
Someone may think why would I invoke the java interpreter with the DOS "> outfile" command. Well, the reason being, I got a different version of the program that executes a query and I want it to create a delimited text file that contains the resultset of the query, so that I can then import it to Access, Excel, or whatever. But, because of this problem, I can't modify the query result without having to either run the application again and created another file name with the same result or re-boot. Of course, this would be silly.
Any help in how I can modify my program or any GUI-program so that if I invoke the DOS "> outfile" command, the outfile won't be "locked" would be greatly appreciated. Thanks. If you want my program, you can e-mail me or run any sample program from the Swing Tutorial that prints to standard output and just add the " > outfile" to the java interpreter command.
-Dan
[email protected]

Oops sorry, forgot to add the code. Here it is:
BTW, can I edit posts? Oh well...
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.filechooser.*;
public class FileChooserDemo2 extends JFrame {
static private String newline = "\n";
public FileChooserDemo2() {
super("FileChooserDemo2");
//Create the log first, because the action listener
//needs to refer to it.
final JTextArea log = new JTextArea(5,20);
log.setMargin(new Insets(5,5,5,5));
log.setEditable(false);
JScrollPane logScrollPane = new JScrollPane(log);
JButton sendButton = new JButton("Attach...");
sendButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JFileChooser fc = new JFileChooser();
fc.addChoosableFileFilter(new ImageFilter());
fc.setFileView(new ImageFileView());
fc.setAccessory(new ImagePreview(fc));
int returnVal = fc.showDialog(FileChooserDemo2.this,
"Attach");
if (returnVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
/** The next 2 lines I added, the rest of the code is original taken from the Swing Tutorial **/
System.out.println("You chose a file named: " +
fc.getSelectedFile().getPath());
log.append("Attaching file: " + file.getName()
+ "." + newline);
} else {
log.append("Attachment cancelled by user." + newline);
Container contentPane = getContentPane();
contentPane.add(sendButton, BorderLayout.NORTH);
contentPane.add(logScrollPane, BorderLayout.CENTER);
public static void main(String[] args) {
JFrame frame = new FileChooserDemo2();
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
frame.pack();
frame.setVisible(true);

Representating Hierarchical (Parent-Child) relation graphically using Swing

Hi,
I have to represent a hierarchical data which is having Parent-Child relation using Swing. I am not able to upload the image overhere, so I am represnting the data in such a way so that one can understand this problem. If anyone knows how to upload image on Sun forum, please let me know it will be great help for me.
Parent Root - A
Child of A - B, C, D
Child of C - E, F, G
Child of F - H
Child of D - J, K
The data needs to be represented in two formats-
1. Tabular Format
I am able to represent data in this format using combination of JTree and JTable. The data is getting represented in tabular format and I am able to expand and collapse the parent nodes to see the childs. The tabular data will look like below structure,
A
I_B
I
I_C
I I_E
I I
I I_F
| I |_H
| I
I I_G
I
I_D
I
I_J
I
I_K
2. Graphical Format
This is the other way in which I need to represent the data. The above shown tabular data needs to represented in graphical form. The end result should look like,
I A I
____________________I__________________________
___I___ __I__ __I__
I B I I C   I I D   I
____________________I____________ ______I________
___I___ __I__ __I__ __I__ ___I__
I E I I F   I I G   I I J   I I   K    I
__I___
I   H   I
Each box representing alphabates will be a component (like JPanel) which will have details about the item to be displayed. The parent and child should be connected with each other using line. This representation should be created at runtime using the hierarchical data. Also the parent and child relations should be expandable/collapsible as they are in JTree.
I am not able to find any component or any solution in Swing which can provide me this graphical representation. It will be great help if anyone can help me out in this.
Thanks in advance.

Sorry for inconvinience for the data representaion in graphical form. I don't know how this get jumblled. Please try to figure out the tabular/graphical representation using pen and paper as forum is not providing any help to upload an image.
Sorry again for inconvinience.
Thanks
Manoj Rai

Using Swing applet to write data to file on SERVER

Hello,
I'm in the process of writing an applet using Swing (SDK v1.4.2). Here's the deal. The JApplet calls a JPanel, which will be used by customers on my site to enter data. I'm adding a <Save> button to the "form" which is supposed to write data to a file on the server (in order to preserve the customer's preferences).
Please note that I am NOT attempting to write data to the customer's hard disk. That requires digital certificates, etc. which I am trying to avoid for now.
Instead, I am using the URL class to access the file:
URL page = new URL("http://www.whatever.com/mycustomers/preferences.txt")
I then use the URLConnection class to establish the connection:
URLConnection conn = this.page.openConnection();
conn.setDoInput(true);
conn.setDoOutput(true);
conn.connect();
etc...
I've created a text file (preferences.txt) on my web site. Using the classes InputStreamReader, BufferedStreamReader, and StringBuffer, I can successfully read the file into a JOptionPane in my applet.
The problem comes when I try to write data TO this file. I know the file exists because the applet can read it. I've set the permissions on the file to 666. I've got all of the appropriate syntax within a try statment that catches an IOException. I also have JOptionPanes all over the place to let me know where the program is. I've tried different combinations of output streams like BufferedWriter, BufferedOutputStream, StringWriter, but the file does not get updated. When the applet runs, it does not throw any exceptions, not even when I change the URL from "HTTP://www.whatever.com/prefs.txt" to "HTTP:/www.whatever.com/prefs.txt" (only one slash on HTTP, shouldn't I get a MalformedURLException?)
I apologize for all the background, but I thought you might need it. The bottom line is:
1) Can an applet write to a file on a remote server (not local hard disk)?
2) If so, what (if any) caveats are there?
3) Is there a way to check for file existence or be able to create a new file?
4) I'm using the HTTP protocol - is there some restriction that prevents an applet from writing to a file using that protocol? If so, is there a workaround?
5) Assuming that creating/writing a file using the method I've described is possible, what would be the appropriate output streams to use? (Currently, I'm using OutputStreamWriter with BufferedWriter).
I've been struggling with this for a while. Any help/suggestions would be appreciated.
Thanks
P.S. I also posted this message on the Applet development forum, but I've received no response as of yet.

Http servers support PUT as a mechanism to upload data to a specified URL. Get on the other hand which is what most people are familiar with is how you retrieve that data. The basic URLConnection is an abstraction of the Http connection which can be used for GET and POST operations by default based on doInput(true|false).. If you which to use any of the http methods other than GET|POST you will have to cast the URLConnection to HttpURLConnection so you can gain access to the specific Http functionaility that could not be abstracted.
Since you are using a hosting service the chances are that you won't be able to use HTTP PUT on their server. Most servers do not support HTTP PUT without configuring them todo so. Now Apache allows localized config through the .htacess file. It might be possible (keep in mind I am not an apache expert) to configure a particular directory to allow HTTP PUT using this .htacess file it may not be possible. You will have to consult the Apache web server documentation for that answer.
But regardless you can use the HttpURLConnection and the PUT method to send data from your applet to the server. In fact that is the preferred way to do this. If you can not configure your web server to support that method then you will have to develop a Servlet to do it. A servlet has several methods such as doGet(), doPost(), and doPut(). You would override the doPut() method get the URI path create a file and a FileOutputStream to that file, get from the request the inputstream, possibly skip the http headers, and then write byte for byte the incoming data to your OutputStream until you reach the end at which point you would close the OutputStream and send an Http Response of some sort. Typically in HTTP it would be 200 OK plus some web content. You content can be empty so long as your applet recognizes that is what it should expect...
And away you go...

Help for a begginer using swing

Basically I need help with a program for a school project. i am not looking for a quick answer but rather some pointers in the right direction. This is my first time using swing and my first project is to create a blackJack game. I am having trouble with functionality. there are problems on tab 2 with almost all the buttons. any help would be greatly appreciated. since i didnt have enough room for all my code i posted it online to be accessed at this site: [https://code.google.com/p/blackjackgui-alpha/]

private void jTextField2ActionPerformed(java.awt.event.ActionEvent evt) {
String betString = jTextField2.getText();
betString = Integer.toString(bet);// TODO add your handling code here:
total = total - bet;
private void jMenuItem1ActionPerformed(java.awt.event.ActionEvent evt) {
    System.exit(0);        // TODO add your handling code here:
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    String name = jTextField1.getText();
    String prefix = (String)jComboBox1.getSelectedItem();
    jLabel2.setText("Hello " + prefix + name + " and welcome to blackJack please press the tab labeled BlackJack");
      jLabel3.setText("Welcome to you personal blackJack game " + prefix + name + " your cards are" + card1 + "(" + card1s + ") and " + card2 + "(" +card2s + ") your hand total is " + handTotal);
    jLabel5.setText("This is where you may see the Dealers information " + prefix + name);
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
          handTotal = card1 + card2;
          if(handTotal > 21)
              jLabel3.setText("You busted press hit");
              handTotal = 0;
          handTotal = card1+card2;
          dealerHandTotal = 0;
          dealerHandTotal = dealerCard1 + dealerCard2;
          handTotal = handTotal + card3;
      jLabel3.setText("You have hit and recieve " + card3 +   "your total is " + handTotal);
            jLabel5.setText("Dealer hits and recieves " + dealerCard1 + "(" + dealerCard1s + ") and " + dealerCard2 + "(" + dealerCard2s + ") Dealer total is " + dealerHandTotal);
    if(handTotal > 21)
      jLabel3.setText("I am sorry, you busted with: " + handTotal + "Please press hit to begin a new round");
handTotal = 0;
      card1=card1;
      card2 = card2;
    else if( handTotal == 21)
          total = total + (bet*2);
      jLabel3.setText("BLACKJACK!!! your total is now: " + total);
      handTotal = 0;
      dealerHandTotal = 0;
    else if(handTotal == dealerHandTotal)
        jLabel3.setText("PUSH ...house automatically wins");
                   jLabel5.setText("PUSH ...house automatically wins");
                   handTotal = 0;
                   dealerHandTotal = 0;
    else if(dealerHandTotal < 17 || handTotal > dealerHandTotal) {
                dealerHandTotal = dealerHandTotal + dealerCard1;
    else if(dealerHandTotal == 21)
        jLabel5.setText("DEALER GETS BLACKJACK!!")
                dealerHandTotal = 0;
        dealerHandTotal = dealerCard1+dealerCard2;
        handTotal = 0;
        handTotal = card1 + card2;
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
    jLabel3.setText("You have stood at " + handTotal);   // TODO add your handling code here:
private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {
    jLabel3.setText("You have folded at your total of: " + handTotal);
    jLabel5.setText("You have folded at you total of:" + handTotal)
    handTotal = 0;
    dealerHandTotal = 0;
}                  Sorry i thought it would be more convenient for the code to be on another page..my bad
Edited by: rightWingNutJob on Mar 4, 2010 2:07 PM
Edited by: rightWingNutJob on Mar 4, 2010 2:30 PM

How to use Swing in a web Application

Can you suggest me some good PDF/tutorial or some good site for reading about using SWING in a Web Application.
In our web application we plan to use JSP/Struts for the presentation layer. However there are a few screens that require some advanced UI like color coded assets and a graphical version of Outstanding Vs Available limit. We are wondering whether we should use SWING for these screens. Do you think this is a good idea or is there a better apprach to deal with this
What are the disadvantages of using SWING VS JSP/Servlet in a Web environment. Is there a site or pdf where i can get information about this.

I'd say the biggest disadvantage is that your client machines have to download and install the bloody java plug in.
What you write about your UI ain't half vague. What the deuce is a "color coded asset"? Is it
interactive? If not, could it be represented by an image? If so, even if it is a non-static image, it is a simple
matter for your webapp to generate the image on the fly. Many web app tutorials demonstrate that.

How to use Swing in a Web applicatrion

Can you suggest me some good PDF or some good site for reading about using SWING in a Web Application.
In our web application we plan to use JSP/Struts for the presentation layer. However there are a few screens that require some advanced UI like color coded assets and a graphical version of Outstanding Vs Available limit. We are wondering whether we should use SWING for these screens. Do you think this is a good idea or is there a better apprach to deal with this
What are the disadvantages of using SWING VS JSP/Servlet in a Web environment. Is there a site or pdf where i can get information about this.

Applet/HTML page combinations are used often when a portion of a page requires Swing/AWT capabilities, e.g. administration consoles for Weblogic and JBoss are designed this way. The page is typically divided with frames that contain either applet or HTML code.
A

Desktop like view of files and folders using Swing

I have an application for upload/download of files from a server. The application is developed using swing and it works perfectly. Currently, the files and folders are displayed in a table view(using jtable) in which the file/ folder will be displayed with icon and extension in each row.
I need to display these files and folders in a desktop like view. How can I implement this?
Anees

Any sample demos or links? Thats why people give you links to the Swing tutorial. The hope is that you will actually look at the Table of Contents and read the tutorial before you post a question.
Or you could even read the JList API to find a link to the tutorial.

File system using swing

Hi,
I am developing a standalone application using swing and awt. My requirement is to show directory structure like windows explorer. Do we have any built-in components in swing get this Done.
Thanks
mmb

herez a sample code for you... not commented at all...
import java.io.File;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.event.TreeExpansionEvent;
import javax.swing.event.TreeWillExpandListener;
import javax.swing.filechooser.FileSystemView;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
public class JExpTree extends JTree{
     FileSystemView fsv=null;
     File home=null;
     File[] temp=null;
     DefaultMutableTreeNode root=null;
     DefaultTreeModel treeModel=null;
     DefaultTreeCellRenderer treeRend=null;
     public JExpTree(){
          initialize();
          setModel(treeModel);
          setShowsRootHandles(true);
          addTreeWillExpandListener(new TreeWillExpandListener(){
               public void treeWillCollapse(TreeExpansionEvent e){
                    ((DefaultMutableTreeNode)(e.getPath().getLastPathComponent())).removeAllChildren();
                    ((DefaultMutableTreeNode)(e.getPath().getLastPathComponent())).add(new DefaultMutableTreeNode(null));
               public void treeWillExpand(TreeExpansionEvent e){
                    expandPath((DefaultMutableTreeNode)(e.getPath().getLastPathComponent()));
     public void expandPath(DefaultMutableTreeNode d){
          d.removeAllChildren();
          File[] tempf=((TreeFile)d.getUserObject()).getFile().listFiles();
          DefaultMutableTreeNode tempd=null;
          for(int i=0; i<tempf.length; i++){
               tempd=new DefaultMutableTreeNode(new TreeFile(tempf));
               if(tempf[i].isDirectory())
                    tempd.add(new DefaultMutableTreeNode(null));
               d.add(tempd);
     public void initialize(){
          fsv=FileSystemView.getFileSystemView();
          root=new DefaultMutableTreeNode(new TreeFile(fsv.getHomeDirectory()));
          expandPath(root);
          treeModel=new DefaultTreeModel(root);
     public static void main(String a[]){
          JFrame j=new JFrame("TestFrame");
          j.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          j.getContentPane().add(new JScrollPane(new JExpTree()));
          j.pack();
          j.setVisible(true);
import java.io.File;
import javax.swing.filechooser.FileSystemView;
public class TreeFile {
     private File file=null;
     public TreeFile(File f){
          file=f;
     public File getFile(){
          return file;
     public String toString(){
          return FileSystemView.getFileSystemView().getSystemDisplayName(file);

Build a xml editor using swing

I would like to know a simple way to build a xml editor using swing. The editor should present the xml in a tree structure, THe user should be able to modify the xml in the editor and save it.

Try reading this from [The XML Tutorial|http://java.sun.com/j2ee/1.4/docs/tutorial/doc/JAXPDOM4.html#wp64247] for discovering how to display the XML tree first, this is the first point to build a XMLNotepad like solution.

Using swing on j#

Similar Messages

Maybe you are looking for