With it, you can not only get information about a class, but add new fields, new methods, create new classes. Some have tried to generate source code, compile to bytecode and load into their program, but trust me - using a solid bytecode manipulation API is far, far easier. If you need more than information, and actually want to manipulate the classes, you want bytecode manipulation. Remember you can lookup a class object (as long as it's on the classpath at runtime) with Class.forName('M圜lass') and reflect on the resulting Class. Reflection is useful for discovering information about the classes in the program, and of course you can walk the entire tree without having to find source code, or parse anything.

With it, given a Class object you can, for example, get the types of a specific field, list all fields and iterate over them, etc.: Class clazz = User.class įield field = clazz.getDeclaredField('var') If you just need information about a class at runtime, just use the Java Reflection API. Additionally, you'll need to keep it all organized when you want to find it, much like a classpath, whereas the Class objects are much easier to get hold of, and manipulate, without having to parse text again. JSE source code is available online, as are many open source libraries, but that may not always be the case. Without knowing what you really want to do with the information, we can't be very precise with our recommendations, but I'd start by steering you away from source code if possible. You may want one of several possible solutions. Is there any way to obtain the java source from a class name? For example.

Source code java example