Question

I’m new in using the log4j package and I don’t see the error:
This is a very simple and straightforward code sample:

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class TestLogger {

    private static Logger logger;

    public static void main(String[] args) {

        logger = LogManager.getLogger(TestLogger.class);
        logger.info("Hello");

    }
}

When I try to compile I get this error:

Exception in thread “main” java.lang.NullPointerException at
org.apache.logging.log4j.LogManager.getLogger(LogManager.java:129) at
my.package.logging.TestLogger.main(TestLogger.java:15)

I am wondering what on earth it’s all supposed to mean …

Could you help here?

Answer 1

You’re most probably missing one of the dependencies. This is easy reproducible if you only include in your classpath the log4j-api-2.0-beta1.jar file.

If you downloaded the binary distribution, include also the log4j-core-2.0-beta1.jar in your classpath. If your using Maven, put this in your pom.xml:

  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.0-beta1</version>
  </dependency>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.0-beta1</version>
  </dependency>