I am attempting to have a simple "Submit" button parse particular information to an I/O. The button is jButton1 and the source textField is jTextField1 (for example). In Java UI Creation with Netbeans there is a lot of generated uneditable code that is written. I noticed my ActionListener event is in this generated code;
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
Next I went ahead and added an ActionPerformed and some other code here:
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// Declaration of Writer I/O
File outFile;
FileWriter aFileWriter;
PrintWriter aPrintWriter = null;
// Declaration of String for Output
String customerNumber = jTextField1.getText(); // Customer Name
String customerSAddress = jTextField2.getText(); // Customer Street Address
String customerCAddress = jTextField3.getText(); // Customer City
String customerStAddress = jTextField4.getText(); // Customer State
String customerZAddress = jTextField5.getText(); // Customer Zip Code
String customerTelephone = jTextField9.getText(); // Customer Phone
String productSelection = jTextField7.getText(); // 1 Desktop, 2 Laptop or 3 All-In-One
String productQuantity = jTextField8.getText(); // Quantity
// Creation of outputStr
String outputStr = "Customer Name: " + customerNumber + ", " + // CreateString outputStr
"Customer Address:" + customerSAddress + " " + customerCAddress +
" " + customerStAddress + " " + customerZAddress + ", " +
"Customer Phone Number: " + customerTelephone + ", " +
"Customer Producton Selection: " + productSelection + ", " +
"Product Quantity: " + productQuantity; // Send to FileWriter after...
try{
outFile = new File( "Order Information.txt", "UTF-8");
aFileWriter = new FileWriter(outFile);
aPrintWriter = new PrintWriter(aFileWriter);
aPrintWriter.println(outputStr);
} // End try
catch (IOException error){
System.out.println("I/O Error, Contact Admin!");
} // End Catch
finally {
aPrintWriter.close();
} //End Finally
}
My issue is ... I have no syntax errors, however whenever I press "Submit" in my console I have about 12 different errors ... They are here:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
I/O Error, Contact Admin!
at my.RAConsultUI.RAConsultUI.jButton1ActionPerformed(RAConsultUI.java:345)
at my.RAConsultUI.RAConsultUI.access$900(RAConsultUI.java:14)
at my.RAConsultUI.RAConsultUI$10.actionPerformed(RAConsultUI.java:217)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:289)
at java.awt.Component.processMouseEvent(Component.java:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:694)
at java.awt.EventQueue$3.run(EventQueue.java:692)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:708)
at java.awt.EventQueue$4.run(EventQueue.java:706)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)
It seems I am not using the Java UI syntax correctly, could I have somebody look over my shoulder and possibly point me in the right direction?
"I/O Error, Contact Admin!" is printed hence "Order Information.txt" file were not found, hence aFileWriter and it's print wrapped instance aPrintWriter is still null, and that is why, you are having a NullPointerException when you are trying to close it by invoking close() function on a null instance in finally block:
finally
{
aPrintWriter.close(); // <------ here NPE, isn't it ?
}