To compile the code in this chapter, you need to add the javax.jnlp library (released from Sun) in your classpath. It is freely available through the Java Developer Connection or more quickly from the Java Web Start product page at http://www.javasoft.com/products/javawebstart.
The services offered by the JNLP Client to launched applications are always invoked by obtaining a service object from the javax.jnlp.ServiceManager class (as shown in the following code):
service = (ExtensionInstallerService)ServiceManager.lookup("javax.jnlp.ExtensionInstaller Service");
Once obtained, the particular service object clients can use it as needed. We won't discuss the API details here (have a look at Appendix B, “The JNLP Specification,” or ...