Hello, I have a question... I just want to know briefly how I develop a library for my plugins. I looked at this tutorial for that: https://www.spigotmc.org/wiki/creating-external-libraries/ I have created a project for myself, as in the tutorial and included practically exactly the same functions. Then I added a new dependency in Maven. Code: <dependency> <groupId>de.sharpadogge</groupId> <artifactId>test-library</artifactId> <version>1.0.0</version> <scope>provided</scope> </dependency> I can compile my plugin without getting errors and auto-complete works as well (JetBrains IntelliJ is used). However, when I start my test server, I get the following error: Code: java.lang.NoClassDefFoundError: de/sharpadogge/lib/TestLibrary at de.sharpadogge.plugin.Plugin.onEnable(Plugin.java:20) ~[?:?] The line of code that causes this error message is this (the same as in the tutorial): Code: // in onEnable() TestLibrary.setPlugin(this); Now my question is how I can use this external library. Does the test-library.jar need to be in a specific folder? Or do I have to change something in my IntelliJ settings? Or in my pom.xml? I have absolutely no idea. Thanks for reading through my problem description, and thanks in advance for the help.