NPE in DefaultPluginManager.stopPlugin

[xiyoufang]

If plugins directory is null, load and start a Plugin, finally stop plugin ：
Exception in thread "main" java.lang.NullPointerException at ro.fortsoft.pf4j.DefaultPluginManager.stopPlugin(DefaultPluginManager.java:340) at ro.fortsoft.pf4j.DefaultPluginManager.stopPlugin(DefaultPluginManager.java:317)
If plugins directory is not null, not have this Exception.
pluginsDirectory is null , dependencyResolver can't instanced

[decebals]

I will take a look. Pull Request is welcome.

[decebals]

You are right, the value of dependencyResolver at line 340 in DefaultPluginManager.stopPlugin(pluginId) but I don't understand how it's possible to get to that line in this context.
If the plugins directory is null or empty if you call DefaultPluginManager.stopPlugin(pluginId) the first line sin this method are:

if (!plugins.containsKey(pluginId)) {
    throw new IllegalArgumentException(String.format("Unknown pluginId %s", pluginId));
}

So, I believe that something is strange in your code.
Can you give me more details about this issue?

[xiyoufang]

1. Call loadPlugins(). Because plugins Directory is empty, defaultPluginManager.java 392 line directories.length == 0 is true. dependencyResolver is null .
2. Call loadPlugin(File pluginArchiveFile) and startPlugin(pluginId). plugins is not empty, dependencyResolver is null.
3. Call stopPlugin(pluginId). plugins.containsKey(pluginId) is true, but dependencyResolver is null, in DefaultPluginManager.java 340 line throw NullPointerException.

[MsDakota13]

By adding a small check on dependencyResolver not being null or else skipping the line where it trigger the NPE fixed the issue for me. It happens for plugins without dependencies in most projects both with version 0.13 and the snapshot version of 0.14. Basically this confirms the finding xiyoufang mentioned in his/her comment. This bug even occurs by using the sample code only in the sample projects. I am not sure if you have this fixed yet. If it has been fixed ignore this post all together.

[decebals]

@heyokajan Thanks for comment. I will check if the fix is already pushed on github and if it's not then I will push the fix.

[decebals]

@xiyoufang, @heyokajan Please try the fix and confirm that the issue is resolved.

[justinnichols]

Is there a workaround for this until the next release?

[decebals]

I don't have any feedback from people if this issue is resolved or not on trunk. I updated the SNAPSHOT version.
All I want to add for next version is a protection for #82 (extension not found) because is very time consuming for me to offer support for this kind of problem.
If this issue is a stopper for you and if the bug is resolved in trunk (please test yourself) I can release a new version that will contain this bug fix.

[justinnichols]

I will test based on the SNAPSHOT, thanks!

[justinnichols]

Confirmed, 0.14.0-SNAPSHOT fixes this issue for me.

[justinnichols]

I can stay on the snapshot for now, but definitely would love to go back to release once you feel 0.14.0 is ready.

[decebals]

@justinnichols Thank you for confirmation