Java Blogs

Heap size: java.lang.OutOfMemoryError

2007-11-13T06:43:00.000-08:00

To avoid java.lang.OutOfMemoryError when dealing with swing programming or IO files with large size, just tune the heap size or your java virtual machine:

Syntax:

java -Xms_initial heap size_ -Xmx_max heap size_

Default:

java -Xms32m -Xmx128m

In my case, I increased it to 512MB such as

java -Xms32m -Xmx512m

Resources:
[1] http://edocs.bea.com/wls/docs61/perform/JVMTuning.html
[2] http://hausheer.osola.com/docs/5

Good usage of anonymous inner class

2007-10-11T17:34:00.000-07:00

I just found out a good usage of anonymous inner class. Code shown below is an alternative of creating an AbstractTableModel that sets the table editable mode to off.

JTable table = new JTable(){
public boolean isEditable(){
return true;
}
}

The result is clean code plus I can set the table's model to DefaultTableModel with uneditable table cell mode.

Problem on ImageIcon when path is a URL

2007-10-09T07:12:00.000-07:00

I am still figuring out how to add remote icon for a swing component given the URL path of the image. The constructor new ImageIcon(URL) is not working.

Javascript sample

2007-10-08T22:44:00.000-07:00

This blog post exhibits jquery usage to toggle appearance of a phrase.

Click here
Allan here doing js.

Proper execution of Java Swing

2007-10-01T02:06:00.000-07:00

Swing event-handling and painting code executes in a single thread, called the event-dispatching thread. This ensures that each event handler finishes executing before the next one executes and that painting isn't interrupted by events. To avoid the possibility of deadlock, you must take extreme care that Swing components and models are created, modified, and queried only from the event-dispatching thread.

Using SwingUtilities.invokeLater to ensure that the code executes on a special thread.
Threads - lightweight processes that can run concurrently.

The invokeLater method returns immediately, without waiting for the event-dispatching thread to execute the code. This inhibits the deadlock that maybe caused by updating and repainting of GUI component.

Example:

SwingUtilities.invokeLater(new Runnable() {
public void run() {
MyJFrame f = new MyJFrame();
// set center location
f.setLocationRelativeTo(null);
// show GUI
f.setVisible(true);
}
});

Hacking Blogspot

2007-10-01T01:52:00.000-07:00

Project ChickenFoot using Java

2007-09-29T22:17:00.001-07:00

Concept:

Login to friendster and post blog in just 1 click.
The application behaves like chickenfoot.
Java application will be a frame with textarea for blog message and a Post button.
When post button is clicked, a login frame will appear. After supplying login detail, the application will post the message to friendster blogs.
This uses HtmlUnit as html loader and parser.

Retrieve IP

2007-09-29T21:32:00.001-07:00

Sample code for retrieving IP or hostname from given url:

import java.net.InetAddress;
import java.net.UnknownHostException;

public class RetrieveIP {
public static void main(String[] args) {
String site = "www.yahoo.com";
InetAddress ad = null;
try {
ad = InetAddress.getByName(site);
} catch (UnknownHostException e) {
e.printStackTrace();
}// try-catch
System.out.println(ad);
}// main
}// class

// www.yahoo.com/209.131.36.158