Project in multi project setup can't find different projects class

Hello Gradle Community,
I’m stuck on a problem I can’t solve right now:

I have a Multi Project wich has the following structure:

  • core
  • pluginApi
  • plugins/globalOptions
  • plugins/commandPlugin

Where “plugins” is just a directory.

Now I have a couple classes inside “globalOptions”:

  • at.lyze.plugin.globalOptions.extensionpoint.OptionExtension
  • at.lyze.plugin.globalOptions.extensionpoint.OptionHandlerExtension

And one class inside “commandPlugin”:

  • at.lyze.plugin.commandPlugin.CommandPluginTest

The “CommandPluginTest” class references “OptionExtension” and “OptionHandlerExtension” from the other project.

import at.lyze.plugin.globalOptions.extensionpoint.OptionExtension;
import at.lyze.plugin.globalOptions.extensionpoint.OptionHandlerExtension;

List<OptionHandlerExtension> optionHandlers = wrapper.getPluginManager().getExtensions(OptionHandlerExtension.class);
        for (OptionHandlerExtension optionHandler : optionHandlers) {
            logger.warn(optionHandler.getOption(getClass(), "TestOption"));
        }

My gradle build files look like:

“globalOptions”:

dependencies {
    compile project(':pluginApi')
}

“commandPlugin”:

dependencies {
    compile project(':plugins/globalOptions')
    compile project(':pluginApi')
}

When trying to run the “jar” task on every project I get the following error:

Note: Extension found in at.lyze.plugin.globalOptions.GlobalOptions$TestExtension
:plugins/globalOptions:compileJava
:plugins/globalOptions:processResources UP-TO-DATE
:plugins/globalOptions:classes
:plugins/globalOptions:jar
Note: Extension found in at.lyze.plugin.commandPlugin.CommandPluginTest$BlarghExtension
    C:\Users\wml\Desktop\LocalRepos\darkowlbot\plugins\commandPlugin\src\main\java\at\lyze\plugin\commandPlugin\Co    mmandPluginTest.java:3: error: package at.lyze.plugin.globalOptions.extensionpoint does not exist
import at.lyze.plugin.globalOptions.extensionpoint.OptionExtension;
                                                  ^
C:\Users\wml\Desktop\LocalRepos\darkowlbot\plugins\commandPlugin\src\main\java\at\lyze\plugin\commandPlugin\Co    mmandPluginTest.java:4: error: package at.lyze.plugin.globalOptions.extensionpoint does not exist
import at.lyze.plugin.globalOptions.extensionpoint.OptionHandlerExtension;
                                              ^
C:\Users\wml\Desktop\LocalRepos\darkowlbot\plugins\commandPlugin\src\main\java\at\lyze\plugin\commandPlugin\Co    mmandPluginTest.java:52: error: cannot find symbol
    public static class BlarghExtension implements EventProcessorExtension, OptionExtension {
                                                                            ^
  symbol:   class OptionExtension
  location: class CommandPluginTest
C:\Users\wml\Desktop\LocalRepos\darkowlbot\plugins\commandPlugin\src\main\java\at\lyze\plugin\commandPlugin\CommandPluginTest.java:76: error: cannot find symbol
        public void initializeOptions(OptionHandlerExtension optionHandlerExtension) {
                                  ^
  symbol:   class OptionHandlerExtension
  location: class CommandPluginExtensionClass
4 errors
:plugins/commandPlugin:compileJava FAILED

FAILURE: Build failed with an exception.

Have I done something wrong here or why does this fail?
I can provide additional information if needed.

Running gradle 2.9