public synchronized boolean ping() {
        try {
            output.writeByte(ForkServer.PING);
            output.flush();
            while (true) {
                int type = input.read();
                return type == ForkServer.PING;
            }
        } catch (IOException e) {
            return false;
        }
    }
Fills in the jar file used to bootstrap the forked server process.
All the required <code>.class</code> files and a manifest with a
<code>Main-Class</code> entry are written into the archive.

@param file file to hold the bootstrap archive
@throws IOException if the bootstrap archive could not be created
tika-core/src/main/java/org/apache/tika/fork/ForkClient.java