Find a java class that extends an abstract class

Question

How would I find a class that extends another abstract class?

Currently I have this:

public PluginFinder(ClassLoader cl, File f) throws MalformedURLException, ClassNotFoundException {
    super(new URL[]{f.toURI().toURL()}, cl);
    Class<?> jarClass = Class.forName("com.ngxdev.demoplugin.main.MainClass", true, this);
    this.instance = new PluginParser(jarClass).instance;
}

It works, but it's static, I need to find that "com.ngxdev.demoplugin.main.MainClass" without specifying it because the location can be "com.example.ExampleClass" for all I know.

I tried to use: Reflections reflections = new Reflections("my.project.prefix"); but I don't really know how to use it.

I don't understand your question. You want to find all classes in your classpath which are subtypes of a given class? — Sotirios Delimanolis, Oct 08 '15 at 15:21
if you're using an IDE, there is usually a find in all files option, you could search the abstract class name on all files and see what you get. — acolchagoff, Oct 08 '15 at 15:23
No no no, I'm making a plugin loader and I need to find a class that extends Plugin — Community, Oct 08 '15 at 15:24
[`Reflections` can do that.](https://reflections.googlecode.com/svn/trunk/reflections/javadoc/apidocs/index.html?org/reflections/Reflections.html) — Sotirios Delimanolis, Oct 08 '15 at 15:27
That's the problem, I don't know how to use it, and it's an external jar file! — Community, Oct 08 '15 at 15:27
`Reflections` has a number of constructors. You can configure it to scan whatever you want. The javadoc is there. It's all there. — Sotirios Delimanolis, Oct 08 '15 at 15:30
It can scan files, that's what I was missing! Okay I will answer this question myself — Community, Oct 08 '15 at 15:31
If you're making a plugin loader, why not use the [SerivceLoader](http://docs.oracle.com/javase/8/docs/api/java/util/ServiceLoader.html) class which is specifically designed for loading plugins dynamically? — VGR, Oct 08 '15 at 16:18

score 0 · Answer 1 · answered Oct 08 '15 at 15:33

0

Reflections can also scan files, for example:

Reflections reflections = new Reflections(new File("/plugin/example.jar"));

Using this libary

answered Oct 08 '15 at 15:33

Community

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Find a java class that extends an abstract class

1 Answers1