java - Intellij suddenly throwing ClassNotFoundException

Question

I'm at a complete loss here. I have a project on an external hard drive called LenseProject. Inside LenseProject, I have .idea, lib, Natives and SRC folders. I also have a number of text files for reading.

When I left work last night, this all worked fine. Coming in this morning, I'm met with:

Exception in thread "main" java.lang.ClassNotFoundException: QuadTest
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:188)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:113) 

QuadTest being the main class.

Information that I think might be helpful:

• If I comment out the imports, I get the appropriate error messages. (Cannot find symbol, etc).

• I have 9 dependencies, located in liblwjgl-2.9.0jar that are set up in Project Structure -> Libraries.

• The module has LenseProject as the content root, and SRC as the source folder.

• The language level is 7.0

• I have the dependencies set to export in Project Structure -> Modules -> Dependencies.

• In Compiler Output, I have it set to Use Module Compile Output Path, as Inherit Project Compile Output Path gave me "Cannot start compilation: The output path is not specified for module "LenseProject". Specify the output path in Configure Project.

• I have VM option -Djava.library.path=Natives.

• I can compile and run the program through command prompt no problem.

• I was missing my configure options when I started it up this morning. I had to set the SDK again, and libraries.

Answer 1

Open your Idea File --> Project Structure --> Modules ，and then choose problematic module，in the "Paths" tab change selected to "Use module compile output path ".