bas
bas

Reputation: 1678

ClassNotFoundException in IntelliJ IDEA

I have received an IntelliJ project from someone else, but it won't run even the simplest classes for me.

As a quick example, the following class will throw a ClassNotFoundException without compiler errors:

package myPackage;

public class Main {
    public static void main(String[] args)  {
        System.out.println("Hello World!");
        System.out.println("Soon our GUI will start from here!");
        System.exit(0);
    }
}

This will throw the following error:

Exception in thread "main" java.lang.ClassNotFoundException: myPackage.Main
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:260)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:116)

Process finished with exit code 1

The file structure is as follows: <git root>/src/myPackage/Main.java

I have set the 'src' folder as the 'source folder'. My application has no compiler errors. I have invalidated the caches several times, but with no effect whatsoever. In my module settings my module dependencies contain <Module source> and jdk 1.8.

I can't seem to find the answer around here (google) anywhere, and to me it seems like this error has to do with the way IntelliJ handles the project. When I first pulled the project, the src folder had NOT been set to be the source folder, which probably means I may be missing out on other settings as well.

Upvotes: 4

Views: 7521

Answers (1)

user5612499
user5612499

Reputation:

Zack Newsham's suggestion helped me. Here is what I did:

  1. Deleted .iml file
  2. File > New > Project, specified the existing folder with code
  3. completed project setup (Manifest, artifacts).

Now the project runs.

Of course there may be other reasons for ClassNotFound. However when everything seems ok or if the error comes up after it worked before, try these simple steps.

Upvotes: 2

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