Simplified, this is my PlayerListener class:

package io.github.theonlygusti.wizardserver;

import com.nametagedit.plugin.NametagEdit;
// ... import all the bukkit things - I've verified that the bukket-side of the code works

public class PlayerListener implements Listener {
  @EventHandler
  public void onPlayerJoin(PlayerJoinEvent event) {
    Player player = event.getPlayer();
    // get (String)rank from a database - I know this works, I use it elsewhere
    NametagEdit.getApi().setPrefix(player, rank);
  }
}

and this is my simplified pom.xml:

<repository>
  <id>upstream</id>
  <url>http://ci.playmc.cc/plugin/repository/everything/</url>
</repository>
<!-- ... -->
<dependency>
  <groupId>com.nametagedit</groupId>
  <artifactId>nametagedit</artifactId>
  <version>4.1.0</version>
</dependency>

Basically, I would like to prepend a player's rank to their names above their heads whenever a player joins. However, it doesn't work, and instead throws an error - maven compiles it perfectly, but my 1.10 craftbukkit server throws an error whenever a player joins.

Here's the error:

Caused by: java.lang.NoClassDefFoundError: com/nametagedit/plugin/NametagEdit
        at io.github.theonlygusti.wizardserver.PlayerListener.onPlayerJoin(PlayerListener.java:80) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_91]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_91]
        ... 17 more

I'm hoping I've made an obvious mistake, so that this is quick to fix.

Hmm, is NametagEdit installed on the server? Is your plugin attempting to load the class before NametagEdit is loaded? Try putting

softdepend: [NametagEdit]

in your plugin.yml.

Ok whoops

Turns out I didn't have it installed - I had it as a maven dependency, but maven was depending on the runtime environment to expose my plugin to it, which craftbukkit wasn't doing.

However, NametagEdit is now being imported properly, but NametagEdit.getApi().setPrefix(player, rank); is throwing a NullPointerException.

Please use Jenkins build 35 or above. Download here:
http://ci.playmc.cc/job/NametagEdit/35/

What do I put into my pom.xml?

The same stuff here: https://github.com/sgtcaze/NametagEdit/blob/master/documentation/Developers.creole

Current version is 4.1.0.

It has been 5 days without a followup. Please reopen if you need help.