Every Ice-based application needs to initialize the Ice run time, and this initialization returns a
Communicator is a local Java object that represents an instance of the Ice run time. Most Ice-based applications create and use a single
Communicator object, although it is possible and occasionally desirable to have multiple
Communicator objects in the same application.
You initialize the Ice run time by calling
com.zeroc.Ice.Util.initialize, for example:
Util.initialize accepts the argument vector that is passed to
main by the operating system. The method scans the argument vector for any command-line options that are relevant to the Ice run time. If anything goes wrong during initialization,
Util.initialize throws an exception.
The semantics of Java arrays prevents this simple
Util.initialize from modifying the argument vector. You can use another overload of
Util.initialize to receive an argument vector with all Ice-related arguments removed.
Once you no longer need a
Communicator, you must call
destroy on this
destroy method is responsible for finalizing the instance of the Ice run time embodied by this Communicator. In particular, in an Ice server,
destroy waits for operation implementations that are still executing to complete. In addition,
destroy ensures that any outstanding threads are joined with and reclaims a number of operating system resources, such as file descriptors and memory. Never allow your application to terminate without calling
The general shape of our
main method becomes:
The only pitfall with the code above is if you neglect to call
System.exit, the application will continue to run because the Communicator started non-daemon threads.
Another way to initialize and destroy a Communicator is with a try-with-resources statement:
Communicator interface implements
java.lang.AutoCloseable: at the end of a try-with-resources statement, the communicator is closed (destroyed) automatically, without an explicit call to the
If you initialize your communicator in a try-with-resources statement, you may also add a shutdown hook to destroy the communicator.
destroy does not throw any exception and calling
destroy multiple times is perfectly ok. A shutdown hook that calls
destroy is useful to interrupt long-running Ice invocations when the application receives a user interrupt such as Ctrl-C.