Question

Here is my code

package com.my;
import org.apache.log4j.spi.LoggerFactory;
import java.io.*;
import java.util.logging.*;

public class Log {
      public static void main(String[] args) {
      try{
           FileHandler hand = new FileHandler("vk.log");
           Logger log = Logger.getLogger("log_file");
           log.addHandler(hand);
           log.warning("Doing carefully!");
           log.info("Doing something ...");
           log.severe("Doing strictily ");
           System.out.println(log.getName());
      }
      catch(IOException e){
           System.out.println(e)
      }
    }

}

Answer 1

Your code should work if you delete the superfluous log.getLogger(""); statement and fix the imports.

A couple of comments:

• If you have multiple loggers you can selectively turn them on and off. It is conventional to create multiple loggers based on class or package names; e.g.

  Logger log = Logger.getLogger(this.getClass());
  

  or

  Logger log = Logger.getLogger(SomeClass.class);
  

• You are instantiating and associating the handler programmatically. It is a better idea to put the logging configurations into an XML or properties file, and use one of the configurers to load it and wire up the logging handlers. This allows you … or the user … to adjust the logging without modifying your code.

• You should probably READ the log4j introduction document that explains the above and other things about using log4j.

---

The above assumes that you were trying to use log4j. Is you are really trying to use java.util.logging, some details are not exactly right. (And, IMO, you would be better off with using log4j or one of its offspring.)