How do I resolve this Log4J import error (relating to Classpath too)?
configuration, java, log4j, log4j2
Solution
I think you need both the API and the Core jars in your classpath. Follow these instructions for build and install and these for configuration. On the configuration page, the import line you're asking about is `import org.apache.logging.log4j.Logger;`, so the `Logger` class will be pulled from the API jar.
Log4j 2 needs two jars (as opposed to Log4j 1.x which needed one) because of the:
API Separation
The API for Log4j is separate from the implementation making it clear for application developers which classes and methods they can use while ensuring forward compatibility. This allows the Log4j team to improve the implementation safely and in a compatible manner.
Problem
When I run the following simple log4J example, i get an error: ``` import org.apache.logging.log4j.core.*; import java.io.*; import java.sql.SQLException; import java.util.*; public class log4jExample{ /* Get actual class name to be printed on */ static Logger log = Logger.getLogger( log4jExample.class.getName()); public static void main(String[] args) throws IOException,SQLException{ log.debug("Hello this is an debug message"); log.info("Hello this is an info message"); } } ``` and the error reads: ``` Error: package org.apache.logging.log4j.core does not exist Error: cannot find symbol symbol: class Logger location: class log4jExample File: C:\Users\adel\Desktop\various_topics\JavaProjects\log4jExample.java [line: 10] Error: cannot find symbol symbol: variable Logger location: class log4jExample ``` So I believe I added log4J to the classpath correctly, as shown below: And I extracted the `jar` file `log4j-core-2.0-beta4.jar` from the apache directory as so: I'm not sure what's happening - how does the import statement work? i.e the example online tells me to say: ``` import org.apache.log4j.Logger; ``` but what if my directory structure is like this: \apache-log4j-2.0-beta4-bin\org\apache\logging\log4j\core\Logger.java Would I have to say: ``` import org.apache.logging.log4j.core.Logger; ``` instead?