"-javaagent" routines for SLF4J.

The "-javaagent" flag provided in Java 5+ allows for writing agents in Java, which previously was possible in native code only. The full details are available at http://java.sun.com/javase/6/docs/api/java/lang/instrument/package-summary.html. Please notice that code made available to the java agent is also available to the actual program executed.

The slf4j-ext-X.Y.Z.jar file provides such a java agent, which is implemented in AgentPremain.java. It is used by adding a -javaagent flag to the Java command line: E.g.

    java HelloWorld

is changed to

    java -javaagent:/path/to/slf4j-ext-X.Y.Z.jar=OPTIONS HelloWorld

What is actually done, depends on the OPTIONS passed to the agent. These are listed in AgentOptions.java.