Develop Reference

why this code always enters into catch block?

I am creating a simple Calculator. Whenever i try to perform any operation it enters into catch block. here is code. textFields are as follows:
textfield(to show calculation),textField1(to enter operand),textfield_1(to show Solution)
button = new JButton("+");
button.setForeground(Color.BLACK);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try{
ans=Double.parseDouble(textField1.getText());
s=Double.toString(ans)+"+";
textField.setText(s);
reset();
operand=Double.parseDouble(textField1.getText());
ans+=operand;
textField_1.setText(Double.toString(ans));
}catch(Exception x){
JOptionPane.showMessageDialog(null, "Please Enter a valid argument");
}
}
});
button.setBounds(43, 115, 89, 23);
frame.getContentPane().add(button);
button.setToolTipText("ADDITION");
//reset textField1
public void reset(){
textField1.setText("");
}
//............//
java.lang.NumberFormatException: empty String
at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
at sun.misc.FloatingDecimal.parseDouble(Unknown Source)
at java.lang.Double.parseDouble(Unknown Source)
at gui.Calcu$2.actionPerformed(Calcu.java:92)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Your problem is here:
reset();//this makes the textField1 hold an empty String
operand=Double.parseDouble(textField1.getText());
So when you are trying to read and parse a Double from it you are geting a NumberFormatException because you can not convert an empty String into a Double.
One solution to your problem is to create a second JTextField and let the user write the first number he wants to add to the first textField and the second one to the second.Then, when he presses the button to see the result read each number separately, process them and show the result to the screen(either on one of your two textFileds or you could use a third one to display the result).
On the other hand, if you want to have a single textField to handle the user input, you could declare a variable sum outside of all the methods(make it global) and each time you press the "+" button add the value to sum and when the user is done typing numbers just display its String value to the screen.
Additional information on how the event-driven programming works.

Try below code in your button click listner,
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try{
final double val1 = Double.parseDouble(textField1.getText());
ans = val1;
s = Double.toString(ans) + "+";
textField.setText(s);
reset();
operand = val1;
ans += operand;
textField_1.setText(Double.toString(ans));
}catch(Exception x){
JOptionPane.showMessageDialog(null, "Please Enter a valid argument");
}
}
});

Java - JOptionPane.showInputDialog errors

Hello all I am experiencing issues with my JOptionPane.showInputDialog input field.
The issue i am experiencing that is when the cancel button is selected or the OK button is selected with empty or with categorical i am greeted with an error. Any suggestions.
My first attempt at fixing this i changed the c int into an interger therefore i could use an if statement along with null such as
Integer cInterger = new Integer(c);
if (cInterger.equals(null)){
return;}
Along with
cInterger == null
cInterger !=null
But to no avail
int a = 0; //
int b = 0; //
int c = 0; //
if (selected) {
if (command.equals("amount")) {
Scanner readFile = null;
try {
readFile = new Scanner(new FileReader("BANK.txt"));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String account = "";
account = readFile.nextLine();
String amount = JOptionPane.showInputDialog(frame,"Enter an amount"); //assign user input to string amount
a= Integer.parseInt(account); //conversion of scanned string to int for easy subtraction
b= Integer.parseInt(amount);
c = a-b;
try {
if( c == 0){
JOptionPane.showMessageDialog(null,"Granted.","Granted",JOptionPane.WARNING_MESSAGE);}
else if (c > 0){
JOptionPane.showMessageDialog(null,"Granted.","Granted",JOptionPane.INFORMATION_MESSAGE); }
else{
JOptionPane.showMessageDialog(null,"Denied.","Denied",JOptionPane.ERROR_MESSAGE);}
Resulting errors
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: null
at java.lang.NumberFormatException.forInputString(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at java.lang.Integer.parseInt(Unknown Source)
at Options$1MyItemListener.itemStateChanged(Options.java:58)
at javax.swing.AbstractButton.fireItemStateChanged(Unknown Source)
at javax.swing.AbstractButton$Handler.itemStateChanged(Unknown Source)
at javax.swing.DefaultButtonModel.fireItemStateChanged(Unknown Source)
at javax.swing.JToggleButton$ToggleButtonModel.setSelected(Unknown Source)
at javax.swing.ButtonGroup.setSelected(Unknown Source)
at javax.swing.JToggleButton$ToggleButtonModel.setSelected(Unknown Source)
at javax.swing.JToggleButton$ToggleButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$400(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

If you take a look at the JavaDocs, you will find that
Returns: user's input, or null meaning the user canceled the input
So attempting to parse null makes no sense, instead you should be using something like...
if (amount != null) {
a = Integer.parseInt(amount);
//...
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "" seems reasonably obvious.
if (amount != null) {
if (amount.trim().length() > 0) {
//...
} else {
JOptionPane.showMessageDialog(frame, "The amount you entered is invalid");
}
You should also check the account value as well

Searching data from array in Java [closed]

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Improve this question
I have this code, which creates a textfield and a button to let the user search for data in an array:
//Creates a form to search data, list for it and buttons to sort the list.
rightPanel.add(Box.createRigidArea(new Dimension(20, 20)));
final TextField searchTextField;
searchTextField = new TextField ();
rightPanel.add(searchTextField);
rightPanel.add(Box.createRigidArea(new Dimension(20, 20)));
JButton searchConfirmButton = new JButton("Search");
rightPanel.add(searchConfirmButton);
searchConfirmButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e)
{
try {
search = searchTextField.getText();
int index = Arrays.asList(data).indexOf(search);
for (String result : data) {
if (result.contains(search)) {
System.out.println(result);
System.out.println(index);
}
}
} catch (NullPointerException e1) {
}
}
});
But whenever I search for the data, whether it exists or not, the program returns me an nullpointerexception with the following content:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at program.Program$4$1.actionPerformed(Program.java:233)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
In this case, row 233 contains this line if (result.contains(search)) {

data looks like an array type that can hold data values or null pointers. You should try:
System.out.println("Found index: " + index);
for (String result : data) {
if (result != null && result.contains(search)) {
System.out.println("Found result: " + result);
}
//If you are still confused than the right else here will help.
}
If, for example, you split a string with two spaces in a row by space, then depending on your function parameters to split(), you can end up with an empty string in that location and you need to skip it effectively.

Convert vertex label value of the jgraph to array of strings

Basically I have this code to print the cell label of each vertex I click of the jgraph. I am trying to store the values of the cells into a string array. I have tried this:
graphComponent.getGraphControl().addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
ArrayList<Object> objarr = new ArrayList<Object>() ;
if (e.getButton() == 3 && e.getClickCount() == 1) {
long x = e.getX();
long y = e.getY();
Object cell = graphComponent.getCellAt((int) x, (int)y);
System.out.println(graph.convertValueToString(cell));
objarr.add(cell);
}
String[] stringArray = objarr.toArray(new String[100]) ;
}
});
}
I get these errors when i try to click a vertex:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayStoreException
at java.lang.System.arraycopy(Native Method)
at java.util.Arrays.copyOf(Unknown Source)
at java.util.ArrayList.toArray(Unknown Source)
at GUIquery$2.mousePressed(GUIquery.java:498)
at java.awt.AWTEventMulticaster.mousePressed(Unknown Source)
at java.awt.AWTEventMulticaster.mousePressed(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Here is the process to resolve such a problem.
at java.util.ArrayList.toArray(Unknown Source)
at GUIquery$2.mousePressed(GUIquery.java:498)`
Line 498 must be
String[] stringArray = objarr.toArray(new String[100]) ;
Check ArrayList documentation for <T> T[] toArray(T[] a)
When called this tries to store ArrayList<Object> members of type Object in a String[]. So it gave an ArrayStoreException. The root of the problem is that the computer has no idea what type cell is. You declared is as an Object, so that's its type. If getCellAt() returns strings, use String cell.
As a note that is not an elegant solution here, if you had an Object obj_str that you knew was a String, you could cast it with
String str = (String)obj_str;

java NullPointerException when trying to draw

I'm trying to draw a picture based on a random array of numbers. So far I've had partial success, as the background color (white) does come up.
However, the picture does not draw. Instead all I see is the white background and this error:
PixelAvatarGen
XphnX
Black and white or 8-bit color?
0 = B&W, 1 = 8bit
1
Print name to make into avatar.
2
5:2:7:0:3:6:7:0:6:7:7:3:1:4:0:6:5:1:7:4:0:0:5:6:6:3:0:2:3:7:2:4:7:5:4:2:3:6:0:1:4:1:6:4:1:1:1:5:7:5:1:5:4:0:4:5:1:5:6:0:5:4:6:0:0:6:0:0:0:6:7:5:2:6:4:0:1:1:1:7:0:2:1:4:0:2:3:3:3:3:2:6:6:2:6:4:2:7:5:4:7:3:3:3:1:5:1:6:1:3:4:6:0:1:1:2:5:7:4:1:0:2:4:4:4:6:3:7:7:1:0:6:3:6:3:7:6:5:2:5:5:3:5:3:5:4:4:7:0:5:7:4:2:4:5:7:1:0:3:2:7:7:2:3:5:5:2:7:5:6:6:7:4:3:0:7:4:7:1:0:0:7:4:4:3:7:6:0:4:2:7:6:7:3:2:4:2:7:3:0:5:6:6:7:7:2:2:0:2:5:7:6:5:1:0:6:1:5:2:0:7:0:7:0:4:1:0:3:4:3:7:7:4:4:2:7:0:7:4:7:1:6:1:4:4:2:4:7:3:0:4:4:6:6:3:5:
Drawing11
Exception in thread "AWT-EventQueue-0" Drawing11
java.lang.NullPointerException
at xphnx.pixelgen.Screen.paintComponent(Screen.java:25)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at java.awt.Window.paint(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$700(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at xphnx.pixelgen.Screen.paintComponent(Screen.java:25)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$700(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
This is the complete output of the program. The "1" after 0 = B&W and "2" after "Print name to..." are user input.
Here is the Screen.java:
public class Screen extends JPanel {
String[] pixels;
Color[] proxlol;
public Screen(String[] in1, Color[] in2) {
in1 = pixels;
in2 = proxlol;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
this.setBackground(Color.WHITE);
int row = 1, column = 1, row10, column10;
for(int i = 0; i != 256; i++) {
System.out.println("Drawing" + row + column);
g.setColor(proxlol[i]);
if(i == 17 ||
i == 33 ||
i == 49 ||
i == 65 ||
i == 81 ||
i == 97 ||
i == 113 ||
i == 129 ||
i == 145 ||
i == 161 ||
i == 177 ||
i == 193 ||
i == 209 ||
i == 225 ||
i == 241
){
row++;
column = 1;
}
row10 = row*10;
column10 = column*10;
g.fillRect(row10, column10, 10, 10);
System.out.println("Done drawing" + row + column);
column++;
}
}
}
In case needed, Main.java and Arranger.java are on pastebin.
I've got little experience with Swing before. What's going on?

You never assign a value to your class variable proxlol.
public class Screen extends JPanel {
String[] pixels;
Color[] proxlol;
public Screen(String[] in1, Color[] in2) {
in1 = pixels;
in2 = proxlol;
}
}
You assign (to no effect) the uninitialized class variable to the input parameter in2. So, in your paint method when you reference the array of Colors you get an NPE.