log4j2: Location for setting Log4jContextSelector system property for asynchronous logging

Question

I am attempting to set up asynchronous logging (for performance reasons) within REST web methods that currently run in a liberty profile server.

In order to do this, I h

Answer 1

My problem is that no matter where I do this, sometimes it works and logging is very fast, and sometimes it doesn't.

Add that code in a static initializer block in the class that defines your main entry point.

public class MainClass {
    // NOTE: Nothing can appear before this initializer
    // NOTE: This initializer must be in the class that contains your entry point
    static {
        System.setProperty("Log4jContextSelector",
            "org.apache.logging.log4j.core.async.AsyncLoggerContextSelector");
    }

    public static void main(final String[] args) {
        // Do anything you want to here
    }
}

According to the Java specification, static initialization occurs in the order it is declared. Therefore, the System.setProperty call is guaranteed to happen before the Log4j initialization.