Question

I am trying to add a dynamic logging class to my program (for changing where log messages go e.g. System.out or a file). It extends the base abstract Logger class which has a static method log(String). Is it possible to set the logger class and then invoke the log method without making an instance of the logger or using reflection?

Something like this:

    public class MainController {
        private Class<? extends Logger> mLogger;

        // ...

        public void setLogger(Class<? extends Logger> logger) {
            mLogger = logger;
        }

        public Class<? extends Logger> getLogger() {
            return mLogger;
        }

        // ...
    }

    public class BrokenTest {
        // ...
        private void showErrorMessage(String message) {
            mMainController.getLogger().log(message); // Can't call .log on Class
        }
    }

Answer 1

Something like this:

Method method = mMainController.getLogger().getMethod("log", String.class);
Object result = method.invoke(null, message);

This will call a static method named log with a String parameter on the class returned by getLogger().

UPDATE

But from your description, I believe using an interface and separate implementations would be better. This way, you can work with instances and normal polymorphic calls.