CODEWITHSUNDEEP
javauser-interfacegradleintellij-idea
Liam G
Liam G

Reputation: 791

Java - Intellij Can't compile GUI - Exit Value 1

So I am trying to compile a simple GUI in Intellij with Java, but I keep getting an error message when I go to run the code. I was not getting this error yesterday, and nothing has changed since then. The project has a gradle dependency - which is currently empty.

To troubleshoot I have uninstalled and reinstalled both Java 8 and Intellij 2019.1.1 - to no avail.

main

public class application {
    public static void main(String[] args) {
        AppGUI appGUI = new AppGUI();
        appGUI.setVisible(true);
    }
}

gui

import javax.swing.*;

public class AppGUI extends JFrame{
    private JPanel rootLabel;
    private JLabel testLabel;

    public AppGUI() {
        add(rootLabel);
        setSize(400,500);
    }
}

gradle

plugins {
    id 'java'
}

group 'liamgooch'
version '1.0-SNAPSHOT'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.12'
}

I get the following error message:

6:17:13 PM: Executing task 'application.main()'...

> Task :compileJava UP-TO-DATE
> Task :processResources NO-SOURCE
> Task :classes UP-TO-DATE

> Task :application.main() FAILED
Exception in thread "main" java.lang.NullPointerException
    at java.awt.Container.addImpl(Container.java:1095)
    at java.awt.Container.add(Container.java:1007)
    at javax.swing.JFrame.addImpl(JFrame.java:567)
    at java.awt.Container.add(Container.java:419)
    at AppGUI.<init>(AppGUI.java:8)
    at application.main(application.java:3)

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':application.main()'.
> Process 'command 'C:/Program Files/Java/jdk1.8.0_212/bin/java.exe'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 1s
2 actionable tasks: 1 executed, 1 up-to-date
Process 'command 'C:/Program Files/Java/jdk1.8.0_212/bin/java.exe'' finished with non-zero exit value 1
6:17:15 PM: Task execution finished 'application.main()'.

Upvotes: 0

Views: 429

Answers (2)

Abra
Abra

Reputation: 20914

You say it was working? I don't see how. In the code you posted, I don't see where you assign a value to variable rootLabel. Hence it is null and therefore you get a NullPointerException when you call method add of class JFrame with a null argument. It says so in the stack trace you posted...

at AppGUI.<init>(AppGUI.java:8)

Upvotes: 2

John Joe
John Joe

Reputation: 12803

The reason is because you did not initialized JLabel and JPanel in AppGUI class.

rootLabel = new JPanel();
testLabel = new JLabel();

Upvotes: 3

Related Questions