How to configure log4j with a properties file

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();
props.load(new FileInputStream("log4j.properties"));
PropertyConfigurator.configure(props);

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

Properties props = new Properties();
props.load(getClass().getResourceAsStream("/log4j.properties"));
PropertyConfigurator.configure(props);

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

When you use PropertyConfigurator.configure(String configFilename), they are the following operation in the log4j library.

Properties props = new Properties();
FileInputStream istream = null;
try {
  istream = new FileInputStream(configFileName);
  props.load(istream);
  istream.close();
}
catch (Exception e) {
...

It fails in reading because it looks for "Log4j.properties" from the current directory where the application is executed.

How about the way that it changes the reading part of the property file as follows, and puts "log4j.properties" on the directory to which the CLASSPATH is set.

ClassLoader loader = Thread.currentThread().getContextClassLoader();
URL url = loader.getResource("log4j.properties");
PropertyConfigurator.configure(url);

Another method of putting "Log4j.properties" in the jar file exists.

jar xvf [YourApplication].jar log4j.properties

I have this code in my application today

File log4jfile = new File("./conf/log4j.properties");
PropertyConfigurator.configure(log4jfile.getAbsolutePath());

The relative path is from the working directory of the JVM (where the JVM starts).

import org.apache.log4j.PropertyConfigurator;

Import this, then:

Properties props = new Properties();
InputStream is = Main.class.getResourceAsStream("/log4j.properties");

try {
    props.load(is);
} catch (Exception e) {
    // ignore this exception
    log.error("Unable to load log4j properties file.",e);
}
PropertyConfigurator.configure(props);

My java files directory like this:

src/main/java/com/abc/xyz

And log4j directory like this:

src/main/resources

I believe the log4j.properties directory it needs to be in the java classpath. In your case adding the CWD to the classpath should work.

You can enable log4j internal logging by defining the 'log4j.debug' variable.