Help! Multi-Thread in Java Swing!

Hi,
I have a java swing application. The basic logic for the application is, I will input some data and click the "Process" Button.
The application will perform some operation. Currently I can perform one operation at a time.
I have to extend the scope of this application to multiple process at the same time.
like, I will add a table in the application. Whenever I give input and press the "Process" button, the process should be added in the table at the same time I should be able to input and initiate the next operation.
I am not very much experienced in java swing.
Is it possible to do in swing? Can somebody give me some input on this?
Thanks,
Raja.

Check out SwingWorker http://docs.oracle.com/javase/7/docs/api/javax/swing/SwingWorker.html

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import java.awt.event.*;
import java.util.*;
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parent.remove(0);
parent.add( chessPiece );
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parent.add( chessPiece );
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public void mouseMoved(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
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import java.awt.event.*;
import java.util.*;
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//        populateBoard();
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1. As all the threads are calling the
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I have a native DLL that gives me a HBITMAP (Windows handle to bitmap). I have made a JNI wrapper for this that gives me a BufferedImage back. The native code simple gets the actual bitmap for the handle, converts the RGB byte triplets to RGB ints, puts this in a jintArray and creates a BufferedImage.
This all works fine within a single Java thread. If I do this multi threaded (thread 1 calls the native function and several seconds later, thread 2 calls the native function) I keep getting the last image of the first thread. Can enyone help me out?
I know that this is probably a question for MSDN but I just know that they will tell me its a JNI question.
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JNIEXPORT jobject JNICALL Java_somenamespace_getPicture
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jclass jImageClass;
jmethodID jMethod;
jfieldID jField;
jintArray rgbArray;
char *str;
char *charArray;
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int w, h, index, type;
HBITMAP hbmp;
BITMAP bmp;
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jImageClass = (*env)->FindClass(env, "java/awt/image/BufferedImage");
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jField = (*env)->GetStaticFieldID(env, jImageClass, "TYPE_INT_RGB", "I");
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Have you verified what the "native DLL" gives you back on the second call?The HBITMAP handle returned is the same each call (no matter which thread). The actual BITMAP associated with this handle is only updated in the first thread.
How are you determining that the image is the same?If I point the camera (I don't get a stream, I just get individual images) to a moving scene, I get different images for each call from within the first thread. The second thread only gets the latest image from the first thread. There is no concurrency of the threads and all methods are synchronized.
Specifically did you verify that the problem is not that your test code itself is using the same instance?Yes, I tested the native side as well as the Java side. The BufferedImage is always an exact copy of the native BITMAP.
Try printing out the hash for each instance.I have written the image to a file in the native code itself to eliminate anything related to the mechanism of returning the BufferedImage. This had the same result.
The return values of all native calls all indicate successful calls.
I am suspecting the native side of creating a second graphical context for the second thread while it keeps refering to the first context.
(I will start a thread on the MSDN as well and will post here if anything turns up.)

HELP Needed with this error: Exception in thread "main" java.lang.NoClass

Folks,
I am having a problem connecting to my MSDE SQL 2000 DB on a WindowsXP pro. environment. I am learning Java and writing a small test prgm to connect the the database. The code compiles ok, but when I try to execute it i keep getting this error:
"Exception in thread "main" java.lang.NoClassDefFoundError: Test1"
I am using the Microsoft jdbc driver and my CLASSPATH is setup correctly, I've also noticed that several people have complained about this error, but have not seen any solutions....can someone help ?
Here is the one of the test programs that I am using:
import java.sql.*;
* Microsoft SQL Server JDBC test program
public class Test1 {
public Test1() throws Exception {
// Get connection
DriverManager.registerDriver(new
com.microsoft.jdbc.sqlserver.SQLServerDriver());
Connection connection = DriverManager.getConnection(
"jdbc:microsoft:sqlserver://LAPTOP01:1433","sa","sqladmin");
if (connection != null) {
System.out.println();
System.out.println("Successfully connected");
System.out.println();
// Meta data
DatabaseMetaData meta = connection.getMetaData();
System.out.println("\nDriver Information");
System.out.println("Driver Name: "
+ meta.getDriverName());
System.out.println("Driver Version: "
+ meta.getDriverVersion());
System.out.println("\nDatabase Information ");
System.out.println("Database Name: "
+ meta.getDatabaseProductName());
System.out.println("Database Version: "+
meta.getDatabaseProductVersion());
} // Test
public static void main (String args[]) throws Exception {
Test1 test = new Test1();

I want to say that there was nothing wrong
with my classpath config., I am still not sure why
that didn't work, there is what I did to resolved
this issue.You can say that all you like but if you are getting NoClassDefFound errors, that's because the class associated with the error is not in your classpath.
(For future reference: you will find it easier to solve problems if you assume that the problem is your fault, instead of trying to blame something else. It almost always is your fault -- at least that's been my experience.)
1. I had to set my DB connection protocol to TCP/IP
(this was not the default), this was done by running
the
file "svrnetcn.exe" and then in the SQL Server Network
Utility window, enable TCP/IP and set the port to
1433.Irrelevant to the classpath problem.
2. I then copied all three of the Microsoft JDBC
driver files to the ..\jre\lib\ext dir of my jdk
installed dir.The classpath always includes all jar files in this directory. That's why doing that fixed your problem. My bet is that you didn't have the jar file containing the driver in your classpath before, you just had the directory containing that jar file.
3. Updated my OS path to located these files
and....BINGO! (that simple)Unnecessary for solving classpath problems.
4. Took a crash course on JDBC & basic Java and now I
have created my database, all tables, scripts,
stored procedures and can read/write and do all kinds
of neat stuff.All's well that ends well. After a few months you'll wonder what all the fuss was about.

Running a Java Multi Thread Program in database

I have created a multi threaded program in Java and it runs successfully from the command prompt. I want to create a DBMS Job which will wake up at regular intervals and runs the java program(Java stored procedure). Is this possible in 9.2/10G ?? If Yes, will there be any impact on the DB performance/increase memory etc.,
The database (9.2...) resides on a RH 2.3 AS box.
Any ideas...
Thanks,
Purush

Purush,
Java stored procedures cannot be multi-threaded. Well, they can, but the threads will not run in parallel. You may be able to find some more information in the Oracle documentation, which is available from:
http://tahiti.oracle.com
Good Luck,
Avi.

Help with java swing

Hi people!i need some help
Im a new user for java programming language.Well im programming an application using java swing libraries. I have some problems trying to accesing variables from those swing Jpanels. Ill make it clear....
Im using Netbeans...
I have a class for the window (a JFrame) including 2 Jtextfields and 2 Jlabels
import .......
public class myclass extends javax.swing.JFrame{
public double gp;
public double gv;
public G() {
initComponents();
gpnom=this.gpnom;
gvnom=this.gvnom;
private void TXFgpnom(java.awt.event.ActionEvent evt) { //TXField
gpnom= Double.parseDouble(TXFgpnom.getText());
gvnom= Double.parseDouble(TXFgvnom.getText());
.......//theres a lot of more code .for listeners..next...
Now ive created a new file (a new class)in the same package ,but i cant access public variables from swing class
//the next class was created in a new file
public class hi () {
JPanel prin =(JPanel) new myclass().getContentPane(); //ok
double number=gpnom // error variable not found
When i try to get the value of "number" ...i always get "ERROR" And the class for that textfield was public..i think...
HOw can i use variables from that Jpanel?
Id appreciate an answer...
thanx for your help!
Paco

In future Swing related questions should be posted in the Swing forum and camickr will be more likely to answer if you have used code tags to properly format your code.
Luckily this problem does not seem to be Swing related in the least because the public variables you have in your other class are named gp and gv and further when you access public variables (or properties) of a class you must access them by an instance of that class. Which you don't appear to be doing either.

Exception in thread "main" java.lang.OutOfMemoryError(please help me )

Hi All
here my java class trying to read a txt file(which is having size of 60MB).and putting each line into a Vector class. problem is ,upto certain number of line it is reading properly and putting into vector..after that it is giving error like Exception in thread "main" java.lang.OutOfMemoryError..what is the problem and how to rectify this one..anybody help me on this.
actual situation is one txt is there in that 80 lakhs of lines of content is there..java file trying to read each line and put it into vector or stringbuffer and split it into two lines like key=value and put it into hashmap object.then finally iam creating new file(.properties) and writing these hashmap data on it. if you want clearly..please look into below code..
package test.utf8; import java.io.*; import java.util.*; public class AssetUtils
//static StringBuffer stringbuffer = new StringBuffer();
public AssetUtils()
public static void main(String args[]) throws IOException
BufferedReader bufferedreader = new BufferedReader(new InputStreamReader(new FileInputStream("D:\\list.txt")));
Vector vector = new Vector(0x30D40, 50000);
System.out.println(vector.capacity());
Object obj = null;
int n=0;
System.out.println("Reading list:" + new Date(System.currentTimeMillis()));
do
String s = bufferedreader.readLine();
//System.out.println("line no: "+ ++n);
if(s == null)
break;
vector.add(s);
} while(true);
System.out.println("List Read complete:" + new Date(System.currentTimeMillis()));
String s1 = args[0];
System.out.println("S1: "+s1);
System.out.println(vector.capacity());
HashMap hashmap = new HashMap();
System.out.println( "Vector.Size..>>>>>>>>>>>>>>>>.."+vector.size());
for(int i = 0; i < vector.size(); i++)
System.out.println("i value:"+i);
String s2 = (String)vector.get(i);
//System.out.println("S2: "+s2);
if(s2.indexOf("/") != -1)
String s3 = s2.substring(s1.length(), s2.length());
//System.out.println("S3: "+s3);
if(s3.indexOf("/") != -1) {
String s4 = s3.substring(0, s3.lastIndexOf("/"));
//System.out.println("S4: "+s4);
String s6 = s3.substring(s3.lastIndexOf("/") + 1, s3.length());
//System.out.println("S6: "+s6);
StringBuffer stringbuffer=null;
stringbuffer = new StringBuffer();
String s8 = (String)hashmap.get(s4);
//System.out.println("S8: "+s8);
if(s8 != null) stringbuffer.append(s8 + "," + s6);
else
stringbuffer.append(s6);
hashmap.put(s4, stringbuffer.toString());
//stringbuffer.delete(0,stringbuffer.length());
stringbuffer=null;
System.out.println("Opening asset.properties:" + new Date(System.currentTimeMillis()));
File file = new File("D:\\asset.properties");
PrintWriter printwriter = new PrintWriter(new FileOutputStream(file));
String s5;
String s7;
for(Iterator iterator = hashmap.keySet().iterator(); iterator.hasNext(); printwriter.println(s5 + "=" + s7))
{ s5 = (String)iterator.next(); s7 = (String)hashmap.get(s5); } printwriter.close();
System.out.println("Closing asset.properties:" + new Date(System.currentTimeMillis()));

Theres a number of ways you can improve your memory usage:
1) Build you map as you read in your file.
2) Use StringBuffers in your map - do not use "asshaj" + "ashaskj" This is very memory intensive
If you still run out of memory try running the JVM using -Xms128m -Xmx512m or higher

Help! Multi-Thread in Java Swing!

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