private static Options getStopOptions() {
        Options options = new Options();
        options.addOption("preventSystemExit", false,
                "Prevent the stop method from calling system.exit, " + "which would terminate the JVM. This is useful for integration tests.");
        return options;
    }
This value is set to the server's id in the forked process.
tika-server/tika-server-core/src/main/java/org/apache/tika/server/core/TikaServerCli.java