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Java swing GUI absolute positioning

I know that absolute positioning is not recommended, but I need to show my labels randomly scattered as well as randomly changing their positions.
I have researched how to use setBounds but it doesn't seem to work. The following code shows the labels in a Flow Layout, and when I use setLayout(null) it shows a blank frame.
public class GUI extends JFrame{
device mobiles[];
device station;
JPanel pane= new JPanel();
public GUI()
{
setTitle("communication is Key");
setSize(1000, 1000);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
pane.setBackground(Color.WHITE);
int x=0; int y=0;
mobiles= new device[10];
for (int i = 0; i < 10; i++) {
x=randInt();
y=randInt();
mobiles[i]= new device(1,x,y);
pane.add(mobiles[i]);
}
x=randInt();
y=randInt();
station = new device(0,x,y);
pane.add(station);
this.add(pane);
}
and this is class "devices" that extends JLabel
public class device extends JLabel{
ImageIcon mob = new ImageIcon("mob.png");
ImageIcon tow = new ImageIcon("tower.png");
public device(int num, int x, int y)
{ if(num==1)
this.setIcon(mob);
else this.setIcon(tow);
this.setBounds(x, y, 3, 7);
}
}
any help in finding out what the problem is, would be be appreciated.

The following code shows the labels in a Flow Layout, and when I use setLayout(null) it shows a blank frame.
The layout manager sets the size and location of the component.
If you don't use the layout manager, then you are responsible for set the size and location of each component.
Typically I would set the size to equal to the components preferred size.
Also, did you display the x/y value that are randomly generated? Maybe the values are larger than the size of the panel.
and when I use setLayout(null) it shows a blank frame.
What layout is set to null? The panel of the frame. Your code doesn't use the above method. Post the code that you use to cause the problem. We don't want to guess what you may or may not be doing.

thanks to #CasparNoree ... the answer suggested was to initialize the Japnel from the start:
JPanel pane = new JPanel(null);

When you set the layout to null you can set the bounds manually with coordinates.
JFrame jf = new JFrame();
JPanel p = new JPanel();
JButton jb = new JButton();
// this is where you make it so setting the bounds actually does something
p.setLayout(null);
jb.setBounds(100,100,100,100);
p.add(jb);
jf.add(p);
jf.setVisible(true);

Grid layout not working?

I am trying to make a 2x2 grid layout that has a JLabel on the top left, and three buttons on the other three spaces. When I do this, I get the unexpected result of one big button (filling up the entire JDialog) that says "Do you want to push me". I don't know why this result shows up, please help, Thanks!
public void sinceyoupressedthecoolbutton() {
JDialog replacementwindow = new JDialog(); //Like a window
JButton best = new JButton("best");
JButton first = new JButton("FIRST");
JButton second = new JButton("Second");
replacementwindow.setLayout(new GridLayout(2,3,0,0)); //Row, column, distance horizontally, distance vertical
JPanel panel = new JPanel();
replacementwindow.add(panel); //adding the JPanel itself
replacementwindow.add(first);
replacementwindow.add(second);
replacementwindow.add(best);
replacementwindow.setSize(500, 500);
replacementwindow.setTitle("NEW WINDOW!");
replacementwindow.setVisible(true);
}

It's because you set the layout of your JButton, and not of your JDialog
Change
label.setLayout(new GridLayout(2,2,0,0));
to
YES.setLayout(new GridLayout(2,2,0,0));
Also, your variable called label is a JButton, you probably want to change that.

Don't add components to a button. You add components to a panel.
So the basic code should be:
JDialog dialog = new JDialog(...);
JPanel panel = new JPanel( new GridLayout(...) );
panel.add(label);
panel.add(button1);
...
dialog.add(panel);
Also, variable names should NOT start with an upper case character! "Yes" does not follow Java standards. The other variables do. Be consistent!

Put panel and text box in the same frame

How do i put Jlabel and Jtext in the same frame?
if i add the text last, then only the text are showen, thes is my code:
public MatrixFrame(String framname, int width, int height) {
width =7;
height = 6;
JFrame fram = new JFrame(framname);
fram.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
fram.setSize(500,500);
JTextArea text = new JTextArea("Here come Text");
valMatrixPanel = new ValMatrixPanel(height,width,Color.GRAY, Color.black);
JPanel pan = valMatrixPanel.getPan(); // pan is 6*7 panels lock the picture
fram.add(pan);
fram.add(text);
fram.setVisible(true);
}
}

The key to solving this is your understanding how to use layout managers, because this is how Swing decides where to put what and how to size things. First off for a quick easy fix, put all your components into a JPanel, which uses a FlowLayout by default, and then add the JPanel to your JFrame. Don't set the JPanel's or the JFrame's size, do call pack() on the JFrame after adding everything and then finally call setVisible(true).
The better long term answer: read the layout manager tutorials which you can find, among the other Swing tutorials: here.

Try this
you will have to add a import for grid layout
check that
all you need to do is add a grid layout because the textbox overlaps the panel.
so add the line
fame.getContentPane().setLayout(new GridLayout(1,1));
JPanel pan = valMatrixPanel.getPan(); // pan is 6*7 panels lock the picture
fame.getContentPane().setLayout(new GridLayout(1,1));
fram.add(pan);
fram.add(text);
fram.setVisible(true);

use BorderLayout in fram.add()
like this
public MatrixFrame(String framname, int width, int height) {
width =7;
height = 6;
JFrame fram = new JFrame(framname);
fram.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
fram.setSize(500,500);
JTextArea text = new JTextArea("Here come Text");
valMatrixPanel = new ValMatrixPanel(height,width,Color.GRAY, Color.black);
JPanel pan = valMatrixPanel.getPan(); // pan is 6*7 panels lock the picture
fram.add(pan,BorderLayout.WEST);
fram.add(text,BorderLayout.NORTH);
fram.setVisible(true);
}

Inconsistent JFrame layout

I have a JFrame which displays two JSplitPanes (one inside the other).
For some reason the divider location is inconsistent.
What I mean by that is that sometimes its displayed on the correct position where I have set it, while other times it doesn't. When the position is wrong, its wrong for both split panels. Here is the code I am using for the JSplitPanes:
JPanel javaPanel = core.getComponentPanel(2);
JSplitPane splitA = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
javaPanel.getComponent(0), javaPanel.getComponent(1));
double pos = (screenDim.getHeight() * 72) / 100;
splitA.setDividerLocation((int) pos);
JSplitPane mainSplitP = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
new JScrollPane(getCoreComponents()), splitA);
return mainSplitP;
On the JFrame I have a JPanel with CardLayout. To add the mainSplitP I use the following method:
private void setFrameContent(Container content, String title) {
appContent.add(content, title);
CardLayout cl = (CardLayout) (appContent.getLayout());
cl.show(appContent, title);
appFrame.pack();
}
What could be causing this inconsistency ?

JComponents knows own size after pack(), or when they're once time visible on the screen
wrap JSplitPane's setDividerLocation to the invokeLater

How to increase the slow scroll speed on a JScrollPane?

I am adding a JPanel in a JScrollPane in my project.
All is working fine, but there is one problem about mouse scroll using the mouse-Wheel in JPanel. It's speed is very slow on scrolling. How to make it faster?
My code is :
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
objCheckBoxList = new CheckBoxList();
BaseTreeExplorer node = (BaseTreeExplorer)projectMain.objCommon.tree.getLastSelectedPathComponent();
if (node.getObject() != null) {
cmbList.setSelectedItem(node.getParent().toString());
} else {
if (node.toString().equalsIgnoreCase("List of attributes")) {
cmbList.setSelectedIndex(0);
} else {
cmbList.setSelectedItem(node.toString());
}
}
panel.add(objCheckBoxList);
JScrollPane myScrollPanel = new JScrollPane(panel);
myScrollPanel.setPreferredSize(new Dimension(200, 200));
myScrollPanel.setBorder(BorderFactory.createTitledBorder("Attribute List"));

You can set your scrolling speed with this line of code myJScrollPane.getVerticalScrollBar().setUnitIncrement(16);
Here is details.

This bug seems to occur because swing interprets the scroll speed in pixels instead of lines of text. If you are looking for a more accessible alternative to the accepted solution, you can use the following function to calculate and set the actual desired scroll speed in pixels:
public static void fixScrolling(JScrollPane scrollpane) {
JLabel systemLabel = new JLabel();
FontMetrics metrics = systemLabel.getFontMetrics(systemLabel.getFont());
int lineHeight = metrics.getHeight();
int charWidth = metrics.getMaxAdvance();
JScrollBar systemVBar = new JScrollBar(JScrollBar.VERTICAL);
JScrollBar systemHBar = new JScrollBar(JScrollBar.HORIZONTAL);
int verticalIncrement = systemVBar.getUnitIncrement();
int horizontalIncrement = systemHBar.getUnitIncrement();
scrollpane.getVerticalScrollBar().setUnitIncrement(lineHeight * verticalIncrement);
scrollpane.getHorizontalScrollBar().setUnitIncrement(charWidth * horizontalIncrement);
}
Note that swing does calculate the scroll speed correctly when it contains a single component like a JTable or JTextArea. This fix is specifically for when your scroll pane contains a JPanel.