Can multiple loggers use the same handler?

Question

Is it a good idea to use the same file handler in several loggers? I use the Java logging framework and I want different loggers to write into the same log file, but I don't know if this code example below is a good programming style.

import java.io.*;
import java.util.logging.*;

public class Alpha {
    private static final Logger LOGGER = Logger.getLogger(Alpha.class.getName());
    private static FileHandler loggingHandler;

    static {
        try {
            loggingHandler = new FileHandler("logfile.log", true);
            LOGGER.addHandler(loggingHandler);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static FileHandler getLoggingHandler() {
        return loggingHandler;
    }
}

class Beta {
    private static final Logger LOGGER = Logger.getLogger(Beta.class.getName());

    static {
        LOGGER.addHandler(Alpha.getLoggingHandler());
    }
}

Answer 1

The Answer is yes.You can achieve this(for example) by making a singleton log class so any other class or thread tries creating a copy of it, will actually be using the same instance.

Example implementation with java.util.logging:

public class LogMe {        
    private static LogMe logMe;
    private static Logger logger;    
    private static FileHandler fh;
    private static Formatter sf;

    public LogMe() {
    //Make this class a singleton
        if (logMe != null) {
           return;
       }

        //Create the log file            
        try {
        fh = new FileHandler("../xyz/LogFile.log");
    } catch (Exception e) {
        e.printStackTrace();
    }

    sf = new SimpleFormatter();
    fh.setFormatter(sf);            
    logger.addHandler(fh);

    //Part of making this class a singleton
    logger = Logger.getLogger("LogMe");
    logMe = this;        
}

public Logger getLogger() {
    return LogMe.logger;
}
}

Then in your classes you will be using it like this:

 class MyClass1 {
    LogMe logMe1 = new LogMe();
    Logger logger2 = logMe1.getLogger();
    logger.info("X 01");
}