Java Blogging

Hi,
I'm trying to start a blog that will mainly be about Java coding. I'd like to be able to write a short article, followed by attaching code samples for download. I'd also like to be able to give people an account so that they can contribute. Also a forum would be great
Does anyone know of any free services like this? I thought maybe wordpress?
Richard

Richcoleuk wrote:
Whats the best way to get your blog exposure? Just tagging posts etc?If you just tag all your posts with a link to your blog then you are likely to get bad exposure (people accusing you of link spam and so on).
If your posts include links to relevant blog entries from time to time, then you'll get good exposure.
Although it really depends on why you need to get exposure for your blog in the first place.

Similar Messages

Problem with Java Blog RSS feed?

If I click on this feed, I get nothing
http://feeds.feedburner.com/SDNWeblogs_JavaProgramming
When I click on this feed, I get the latest blogs.
http://feeds.feedburner.com/SDNWeblogs_Abap
Is there something wrong with the Java RSS feed?

Hi,
Did you report things to [email protected]?
Eddy

Look for general blog on Java technologies

Hello,
I am greatly interesting in Java and look for active blog on Java technologies. I found 1000 of blogs posted in this forum but many are very specific or not active anymore. Could you please advise me good java blog with regular posting and interesting articles on different part of Java?
thanks
sebastien

To write JNI code for integrating of an activeX is not a simple task. You will face with a number of problems related to COM:
- when and where to call CoInitialize and CoUninitialize,
- how to clean up COM references on Java Application exit,
- when to do Thread Marshal and when it is not needed for COM interfaces;
- how to Marshal and Unmarshal COM parameters in Java methods calls to COM Interface methods, etc.
The best decision is to use some Java-COM Bridge.
My company has developed tools like
- Java-COM Bridge
- Object-Oriented JNI SDKs for C++ and .NET (v1.1,v.2.0) languages (do not mix with JNI wrapper generators). These are an object-oriented maps of the regular JNI SDK,
- Add-Ins for MS Visual Studio v.6.0 and v.7.1 that generate Java wrappers in C++, C#, J#, MCpp, VB for Object-Oriented JNI SDK.
So we know problems you have.
See our site
http://www.javain.com

Help with Exception in thread "main" java.lang.NullPointerException

I got this exception while running the code in Netbeans IDE 6.1. The code is compiling fine...Please tell me what the problem is
Exception in thread "main" java.lang.NullPointerException
at Softwareguide.chooseanswer(Softwareguide.java:32)
at Driver.main(Driver.java:7)
public class Driver
    public static void main(String[] args)
        Softwareguide swguide = new Softwareguide();
        swguide.chooseanswer();
public class Softwareguide
    State test1;
    State test2;
    State test3;
    State test4;
    State test5;
    State subtest1;
    State subtest2;
    State subtest3;
    State subtest4;
    State subtest5;
    State state = test1;
    public Softwareguide()
        test1 = new Test1(this);
        test2 = new Test2(this);
        test3 = new Test3(this);
        test4 = new Test4(this);
        test5 = new Test5(this);
        subtest1 = new SubTest1(this);
        subtest2 = new SubTest2(this);
        subtest3 = new SubTest3(this);
        subtest4 = new SubTest4(this);
        subtest5 = new SubTest5(this);
    public void chooseanswer()
        state.chooseanswer();
   /* public void chooseyes()
        state.chooseyes();
    public void chooseno()
        state.chooseno();
    public State getState()
        return state;
    void setState(State state)
     this.state = state;
    public State getTest1State()
        return test1;
    public State getTest2State()
        return test2;
    public State getTest3State()
        return test3;
    public State getTest4State()
        return test4;
    public State getTest5State()
        return test5;
    public State getsubTest1State()
        return subtest1;
    public State getsubTest2State()
        return subtest2;
    public State getsubTest3State()
        return subtest3;
    public State getsubTest4State()
        return subtest4;
    public State getsubTest5State()
        return subtest5;
    public String toString()
        StringBuffer result = new StringBuffer();
        result.append("\n Starting Diagnostic Test...");
        return result.toString();
}

spiderjava wrote:
the variable state is assigned to test1. This variable(test1) is not initialized anywhere.It is initialized in the c'tor. Which is invoked after the "global" object and attribute initialization. So it is there, but comes too late.
You should definitly not write a technical Java blog and post it all over the place.

Problem in cell selection in JTable Java Swing

hii
I am using JTable that shows data from database. I have developed one functionality. I change one cell value and then select multiple cell. If I press F12 function key then it copies first selected value and past it to another selected cells. it is working properly but when I press F12 it sets the last selected cell in editable mode. I want that all cell which has been pasted should be selected (with default blue colour not in editing mode). I am using ListSelectionListener for JTable Cell Selection and KeyListener for F12 functionality.
Please give some solution
I can not override editCellAt Method because i have already extended JFrame. and i tried to do this with Jtable.getSelectedColumn and getSelectedRow it is displaying the same value, by this how can I get the particular area of selection means Row nd Column Selected.
How would I know the current selection when user selects more than one cell???
Thanks
Edited by: 850979 on 11-Apr-2011 02:13
Edited by: 850979 on 11-Apr-2011 03:59

camickr wrote:
Presumably, JTable installs an action for the F12 key that results in starting editing the last selected cell.
There are no bindings for F12. See the [url http://www.camick.com/java/blog.html?name=key-bindings]Key Bindings listing. (...)
Right.
Of course it doesn't make sense that a F? key should invoke the editorI thought he meant F2 ("edit" on Windows), so that sounded natural.
All KeyEvents are passed to the editor for the cell and the editor is psuedo invoked. That is, the caret is not placed on the text field used as the editor, but the character typed is added to the editor. You can then either use tab/enter to save the text or use the escape key to cancel the editing.Thanks for the explanation. I had never noticed (I kept on double-clicking my JTable cells when I wanted to edit them! :o)
Of course it doesn't make sense that a F? key should invoke the editor, but this is a by product of all KeyEvents being forwarded so you don't have to have special Key Bindings for every character.You're right - as always.
They (Sun) could have filtered out some of the keys such as those, though, because as noted by the OP the current behavior is unintuitive.
To better control when the cell is editable based on the KeyEvent you can override the table with code like <snipped>
As you suggested using a Key Binding will prevent this behaviour as well (but only for that key).Right again, but in this specific case that is acceptable (the developer wants to attach a specific behavior to a specific key only).
OP here is an SSCCE of that second approach:
public class TestKeyBindingsOnJTable {
    public static void main(String... args) {
        final DefaultTableModel dtm = new DefaultTableModel(new String[] {"A", "B"}, 0);
        dtm.addRow(new String[]{"A1", "B1"});
        dtm.addRow(new String[]{"A2", "B2"});
        dtm.addRow(new String[]{"A3", "B3"});
        JTable table = new JTable(dtm);
        table.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_F12, 0), "clear");
        table.getActionMap().put("clear", new AbstractAction() {
            public void actionPerformed(ActionEvent e) {
                dtm.removeRow(0);
        JOptionPane.showMessageDialog(null, table);
}Edited by: jduprez on Apr 8, 2011 9:36 PM

Question of State of Java RTS

While reading recent Java blogs and the likes, I stumbled across a [post on improvements to Java|http://paulhammant.com/blog/at-least-one-unilateral-improvement-to-java.html]. In it, it mentions a [presentation |http://www.adacore.com/wp-content/files/attachments/PaperPresentationAE2006-Brosgol.pdf]comparing Java and ADA, that talks about concerns about Java in the RTS sense in context of DoD 178B.
It indicates the need for "named parameter" and related concerns.
Since this presentation is a few years old...I am curious, are these concerns still true? Would these be suggestions for improving Java RTS?
Eric

The presentation is not very old - only 2006. The concerns are still true as the Java language and the RTSJ have not changed - neither Java or the RTSJ are compliant with DoD 178B. As the presentation indicates a new JSR (now known as JSR-302) was put together to define "safety-crtiical Java" which is a subset of Java and the RTSJ. There are different levels in 302 and depending on the level different language/runtime/API features are disallowed. JSR-302 is still under development.
Re the comment about "named parameters" - Java doesn't have them and is not likely to ever have them. They prevent certain classes of programming error from arising eg: method declared as foo(int x, int y) and is accidentally invoked as foo(my_y, my_x) thus passing the parameters in the wrong order. Named parameters require the call to be made as foo(x=my_x, y=my_y) and so the order is irrelevant. It's hardly foolproof though, you can still do foo(x=a, y=b) when you should have done foo(x=b, y=a).
Edited to add: Having just read that blog entry I don't think he's talking about the same kind of "named parameters" - at least I couldn't recognize them from the blog.
Check out JSR-302 via the jcp.org website for more info.
David Holmes (JSR-282 EG Member)
Edited by: davidholmes on Apr 9, 2008 10:42 PM

Need help with Exception in thread "main" java.lang.NullPointerException

here is the error
Exception in thread "main" java.lang.NullPointerException
at stream.createFrame(stream.java:153)
at chat.createMessage(chat.java:14)
this is where the error is in stream
public void createFrame(int id) {
*buffer[currentOffset++] = (byte)(id + packetEncryption.getNextKey());*
and this is where it comes from in chat
outStream.createFrame(85);
i just cant see whats causeing the exception

spiderjava wrote:
the variable state is assigned to test1. This variable(test1) is not initialized anywhere.It is initialized in the c'tor. Which is invoked after the "global" object and attribute initialization. So it is there, but comes too late.
You should definitly not write a technical Java blog and post it all over the place.

How can I read the last cell of a JTable that a user Enters data

I have a one column JTable with several rows that a user enters data to. Upon entering the last data, the user clicks a button to read all the data from the rows in the JTable and puts them in an arraylist. If the user does not click enter or navigates away from the last cell, then after clicking the button it does not read the last cell entered. Since the user is clicking on a button to indicate he is done entering data on the table, does he also have to hit the enter key to indicate he is done entering the data?
The code below is my tablemodelListener:
public class InteractiveTableModelListener implements TableModelListener {
public void tableChanged(TableModelEvent evt) {
if (evt.getType() == TableModelEvent.UPDATE) {
int row = evt.getFirstRow();
System.out.println("Update row:"+" "+row);
jTable1.setRowSelectionInterval(row, row);
}

Don't forget to use the Code Formatting Tags so the posted code retains its original formatting. That is done by selecting the code and then clicking on the "Code" button above the question input area.
In the future, Swing related questions should be posted in the Swing fourm. (This question has been asked and answered dozens of times).
But there is not need to repost because [Table Stop Editing|http://www.camick.com/java/blog.html?name=table-stop-editing] explains whats happening and give a couple of solutions.

How to get the value from a cell in jTable without click "enter" or "tab"

Hi guys,
I have a simple question. I have a jTable in my screen and when editing a value, but without click "enter" or "tab" I want to get the new value. I have a button update and after editing the value I click the button "update" and I want the new value to be store in my table. If try to get the selected value it is giving the old value. How can I implement this? Any idea? I hope I was clear.
Thanks

[Table Stop Editing|http://www.camick.com/java/blog.html?name=table-stop-editing]

How to change the default hint box color?

How to change the default hint box color on the default Metal LookAF?
I'm trying looking for something with javax.swing.UIManager, but i just find ways to translate the UI.
Any idea?

[UIManager Defaults|http://www.camick.com/java/blog.html?name=uimanager-defaults] shows all the properties of the UIManager.
Although there is no "hint box" component, so I don't know if it will help.

How to clear the selected values in the JCombobox

Hi All,
Can you please tell - how to clear the selected values in the JCombobox
I have four dropdowns in my application, When I click "CLEAR" button, what ever the values selected in the four drop downs should go off and view as "SELECT" in all the dropdowns.

In addition to the above you should also check out [Combo Box Prompt|http://www.camick.com/java/blog.html?name=combo-box-prompt] which makes it easy to display the default prompt.

Finding the position of the end of a line in a JTextPane

I'm trying to make a JTextPane which expands horizontally if the text being typed in it reaches the right hand edge. To do this I need to know the position in the Document of the end of the current line.
I've managed to write a method which expands the JTextPane vertically using getEndPosition() in AbstractDocument.
There is an endLineAction in the DefaultEditorKit which moves the Caret to the end of the line but I don't want to move the Caret, just find the position of the end of the line. I did have a method before which moved the Caret to the end of the line, stored the position and moved it back but that wasn't suitable.
I suspected the answer was to do with the View but I can't figure out how the View relates to the JTextPane or Document.
Can anyone help?

Well, personally I don't think its a good idea to keep changing the size of the text pane as text is being typed and I doubt the solution will be as easy as you think.
As you type the text will automatically wrap so it will be a little late trying to change the width after the text has wrapped, which means you would need to increase the width "before" text is typed. But then you have another problem because you don't know how much to increase the width by since a single character could be typed or a string of text could be pasted into the text area (people always forget about pasting when doing stuff like this).
Also if text is removed you would need to iterate through all the line to find the longest line and reset the width.
Anyway the only way to know the width would be to play with the modelToView() method. If you want to find the end of the current line then you can use the Element.
Check out my [Text Utilities|http://www.camick.com/java/blog.html?name=text-utilities] class which might give you some ideas on how to use the Element class and modelToView() method.
which has example of using the above Class and method that might give you some ideas.

To change the width of a Table Column

Hai Developers..................
I have problem with the Table Column Width.
When am on search state.
The search results are showing in a table.
At that time i want to change the width of the each column with respect to the column content.
Like the jsp table.......
Pls replay with example......
Thanks.

And that is why Swing related questions should be posted in the Swing forum so we don't spend time guessing what you are talking about.
Darn, the [Table Column Adjuster|http://www.camick.com/java/blog.html?name=table-column-adjuster] didn't show up in that Google search.

How do I render a JCheckBox to an image without ever showing it on screen?

I'm interested in Painting a JCheckBox to a BufferedImage without ever displaying the JCheckBox on-screen.
Here is what I've got so far
//new checkbox
JCheckBox box = new JCheckBox();
//I just want the box, no padding/borders/etc...
box.setBorder(BorderFactory.createEmptyBorder());
// I wish I could call box.getPreferredSize() here, but it returns [0,0]. However, I know that [13,13] is right for my environment
Dimension cbDims = new Dimension(13,13);
GraphicsConfiguration gc = GraphicsEnvironment
                .getLocalGraphicsEnvironment()
                .getDefaultScreenDevice()
                .getDefaultConfiguration();
//create a BufferedImage appropriate for the user's display
BufferedImage bi = gc.createCompatibleImage(cbDims.width, cbDims.height, Transparency.TRANSLUCENT);
box.paint(bi.createGraphics()); //draw... Result is blankHowever, I get the image I'm looking for if I add
JDialog d = new JDialog();
JPanel p = new JPanel();
d.setContentPane(p);
p.add(box);
d.setVisible(true); after I create the JCheckBox.
Edited by: cmumeche on Aug 25, 2009 12:26 PM

Swing related questions should be posted in the Swing forum.
I use the [Screen Image|http://www.camick.com/java/blog.html?name=screen-image] for this. It explains how to get an image of non visible component(s). The trick is to set the size of the component first.
I wish I could call box.getPreferredSize() here, but it returns [0,0].I find that hard to believe. It works fine for me when I use:
component.setSize( component.getPreferredSize() );If you need further help then you need to create a [Short, Self Contained, Compilable and Executable, Example Program (SSCCE)|http://homepage1.nifty.com/algafield/sscce.html], that demonstrates the incorrect behaviour.

How do I save user drawn graphics to a jpeg? (This code doesn't work).

As the title says, I have the code that I think should work but cannot see what is wrong with it:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class SavePaint extends JPanel {
    protected JButton saveButton;
    protected JFrame frame;
    protected int firstX, firstY, currentX, currentY, counter;
    protected JPanel mainPanel = this, panel2;
    protected JButton clearButton;
    protected Color background = Color.PINK;
    protected boolean dragged;
    public SavePaint() {
        JFrame frame = new JFrame("TheFrame");
        frame.add(mainPanel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 400);
        frame.setVisible(true);
        MyMouseListener myMouseListener = new MyMouseListener();
        mainPanel.addMouseListener(myMouseListener);
        mainPanel.addMouseMotionListener(myMouseListener);
    private class MyMouseListener implements MouseListener, MouseMotionListener {
        public void mouseClicked(MouseEvent e) throws UnsupportedOperationException {
            // code
        public void mousePressed(MouseEvent e) throws UnsupportedOperationException {
            firstX = e.getX();
            firstY = e.getY();
            dragged = true;
        public void mouseReleased(MouseEvent e) throws UnsupportedOperationException {
            currentX = e.getX();
            currentY = e.getY();
            dragged = true;
            repaint();
        public void mouseEntered(MouseEvent e) throws UnsupportedOperationException {
            // code
        public void mouseExited(MouseEvent e) throws UnsupportedOperationException {
            try {
                BufferedImage image = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
                Graphics2D graphics2D = image.createGraphics();
                mainPanel.paint(graphics2D);
                ImageIO.write(image, "jpeg", new File("/home/deniz/Desktop/jmemPractice.jpeg"));
            } catch (Exception exception) {
                System.out.println("The exception is: " + exception);
        public void mouseDragged(MouseEvent e) throws UnsupportedOperationException {
            currentX = e.getX();
            currentY = e.getY();
            dragged = true;
            repaint();
        public void mouseMoved(MouseEvent e) throws UnsupportedOperationException {
            dragged = false;
    protected void paintComponent(Graphics g) {
        g.drawLine(firstX, firstY, currentX, currentY);
        firstX = currentX;
        firstY = currentY;
    public static void main(String[] args) {
        new SavePaint();
}An observation that I made is that on top of the white background, there is a dot (is this technically one pixel?) which seems to be the endpoint of what the user (in this case - me) has drawn. The frame has a continous flow of dots display as the user makes them with the cursor. Why isn't the jpeg a continuous flow of dots as well?
Any help would be greatly appreciated!
Thanks in advance!

there is a dot (is this technically one pixel?) This shows a problem with your painting logic.
Whenever the panel is repainted, you only have a single line of code, so only a single pixel is ever drawn. The drawing looks like its working because Swing hasn't asked the panel to repaint itself so you see the cummulative effect of all your drawLine(...) method.
However, try drawing a few lines, then minimize the window and then restore the window. You will only see a single pixel. This is exactly what you see when you try to create the jpeg.
You should probably be using the "Draw on Image" approach suggested in [url http://www.camick.com/java/blog.html?name=custom-painting-approaches]Custom Painting Approaches.
Just for interest sake you can also use the ScreenImage class I suggested to you earlier in your other posting (when you didn't bother to accept the answer I provided, so this will be the last time I help if you don't learn to use the forum properly).
ScreenImage.writeImage(ScreenImage.createImage((Component)mainPanel), "mainPanel.jpg");This will force the class to use the Robot to capture the actual pixels on the screen. Using a Robot is slower then using the paint() method.

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