Java: Jar Byte Array to Instantiated Object

Question

I have an byte array of a jar file and I want to instantiate an object defined by a class contained in the jar. How to I do this? Right now I am stuck at

InputStream inputStream = App.class.getResourceAsStream("/example.jar");
byte[] bytes = IOUtils.toByteArray(inputStream);

I think I will need 2 things, a zip file reader and a class loader. Does that sound like the right direction?

Answer 1

You can use inbuilt URLClassLoader with the resource path you already have and instantiate the class. You dont have to read the bytes yourself

// Create URLClassLoader 
URLClassLoader urlClassLoader = new URLClassLoader(new URL[]{new URL("file://pathToJar/example.jar")});
Class<?> lookupClass = urlClassLoader.loadClass("com.somePackage.ClassName");
Object inst = lookupClass.newInstance();