Factory for creating Log instances. Applications should call the makeNewLogInstance() method to instantiate new instances of the configured Log implementation class.

By default, calling getInstance() will use the following algorithm:

• If Log4J is available, return an instance of org.apache.commons.logging.impl.Log4JLogger.
• If JDK 1.4 or later is available, return an instance of org.apache.commons.logging.impl.Jdk14Logger.
• Otherwise, return an instance of org.apache.commons.logging.impl.NoOpLog.

You can change the default behavior in one of two ways:

• On the startup command line, set the system property org.apache.commons.logging.log to the name of the org.apache.commons.logging.Log implementation class you want to use.
• At runtime, call LogSource.setLogImplementation().