Why do I have a NullPointerException?

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Why do I get a NullPointerException when trying to disable a JFrame?

I get a run-time error NullPointerException whenever I try to click the options button on my JFrame. The JFrame is CharSelection(), and I want to disable it so that I can't click anything on that JFrame and have to click the back button to enable it again. This is the code for the button. JButton btnOptions = new JButton("Options"); btnOptions.addMouseListener(new MouseAdapter() { @Override public void mouseClicked(MouseEvent e) { CharSelection.disabled(); GameMenu.getMusicOption().setVisible...

Answer:

You do not instantiate the frame really. There's a frame = new JFrame() missing somewhere. Plus to do...

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Other solutions

In android programming, why am I getting a NullPointerException error?

I'm fairly new to android programming and I don't understand why I am getting this error. Here is part of the logcat: 03-26 20:41:37.196: ERROR/AndroidRuntime(8250): FATAL EXCEPTION: main 03-26 20:41:37.196: ERROR/AndroidRuntime(8250): java.lang.RuntimeException...

Answer:

I also just started with android so I can't be 100% sure, but it seems you need to create an object...

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Exception in thread "main" java.lang.NullPointerException…

Exception in thread "main" java.lang.NullPointerException at University.offerCourse(University.java:4… at StudentCourseTestProgram.main(StudentCou… Process completed. line 40 public void offerCourse(Course c){ courses.add(c);...

Answer:

You probably haven't initialized cu yet. So, the new operator hasn't been called to create the object...

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Java.lang.NullPointerException…

Hi guys, I am involved in a project which I have to scrape data from the internet I currently have three main classes called TripAdvisorXpath, DOMParser and IValueExtractor, running in three different packages the problem is when running the class called...

Answer:

If you are using Eclipse, the debugger should show you where the error is happening. If it isn't happening...

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Getting java.lang.nullPointerException…

These are the two files: import java.util.Random; public class Game { int aGoals; int bGoals; Team a; Team b; boolean overtimeWin; public Game(Team aTeam, Team bTeam) { a = a; b = b; Random r = new Random(); double c = -1; double d = -1; while(c <...

Answer:

Here is your problem: Team a; //by default the value of a = null, as Team b; //same as a. boolean overtimeWin...

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Why am I getting a nullpointerexception when adding a linearlayout (Android)?

I've posted the code and more information here: http://stackoverflow.com/questions/10126… If someone knows what I have done wrong and could tell me, I'd greatly appreciate it.

Answer:

This could be the technical issue.. Report it to the service to get things fixed... Good luck!

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Answer:

Pointers are used in Java implementation for references (Oracle JDK is implemented in C++) who develop...

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Sasanka Pradhan at Quora Mark as irrelevant Undo

Java: NullPointerException?

Here's the code I have and it is giving a very stupid error! any idea why? public class Main { public Main() { allStudents = new Stu[1]; ...show more

Answer:

We have to allocate the memory individual elements of the array. If you give that no more errors will...

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Answer:

A NullPointerException is an exception thrown by the Java Virtual Machine when you try to access a variable...

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Answer:

This error is corrupt software. Be sure to make a backup of data and pull the battery from the phone...

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Anonymous at ChaCha Mark as irrelevant Undo

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