How to configure log4j with a properties file

Question

How do I get log4j to pick up a properties file.

I\'m writing a Java desktop app which I want to use log4j. In my main method if have this:

   Proper         


        

Answer 1

This is an edit of the answer from @kgiannakakis: The original code is wrong because it does not correctly close the InputStream after Properties.load(InputStream) is called. From the Javadocs: The specified stream remains open after this method returns.

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I believe that the configure method expects an absolute path. Anyhow, you may also try to load a Properties object first:

Properties props = new Properties();
InputStream is = new FileInputStream("log4j.properties");
try {
    props.load(is);
}
finally {
    try {
        is.close();
    }
    catch (Exception e) {
        // ignore this exception
    }
}
PropertyConfigurator.configure(props);

If the properties file is in the jar, then you could do something like this:

Properties props = new Properties();
InputStream is = getClass().getResourceAsStream("/log4j.properties");
try {
    props.load(is);
}
finally {
    try {
        is.close();
    }
    catch (Exception e) {
        // ignore this exception
    }
}
PropertyConfigurator.configure(props);

The above assumes that the log4j.properties is in the root folder of the jar file.