README.md

Ice for Java

Examples | Documentation | API Reference | Building from source

The Ice framework provides everything you need to build networked applications, including RPC, pub/sub, server deployment, and more.

Ice for Java is the Java implementation of the Ice framework.

Sample Code

// Slice definitions (Greeter.ice)

["java:identifier:com.example.visitorcenter"]
module VisitorCenter
{
    /// Represents a simple greeter.
    interface Greeter
    {
        /// Creates a personalized greeting.
        /// @param name The name of the person to greet.
        /// @return The greeting.
        string greet(string name);
    }
}

// Client implementation (Client.java)

import com.example.visitorcenter.GreeterPrx;
import com.zeroc.Ice.Communicator;

class Client {
    public static void main(String[] args) {
        try (var communicator = new Communicator(args)) {
            GreeterPrx greeter =
                GreeterPrx.createProxy(communicator, "greeter:tcp -h localhost -p 4061");

            String greeting = greeter.greet(System.getProperty("user.name"));
            System.out.println(greeting);
        }
    }
}

// Server implementation (Server.java)

import com.zeroc.Ice.Communicator;
import com.zeroc.Ice.Identity;
import com.zeroc.Ice.ObjectAdapter;

class Server {
    public static void main(String[] args) {
        try (var communicator = new Communicator(args)) {
            ObjectAdapter adapter =
                communicator.createObjectAdapterWithEndpoints("GreeterAdapter", "tcp -p 4061");
            adapter.add(new Chatbot(), new Identity("greeter", ""));

            adapter.activate();
            System.out.println("Listening on port 4061...");

            communicator.waitForShutdown();
        }
    }
}

// Greeter implementation (Chatbot.java)

import com.example.visitorcenter.Greeter;
import com.zeroc.Ice.Current;

class Chatbot implements Greeter {
    public String greet(String name, Current current) {
        System.out.println("Dispatching greet request { name = '" + name + "' }");
        return "Hello, " + name + "!";
    }
}

Protocol Compression

Ice for Java implements protocol compression with the bzip2 classes of Apache Commons Compress. Ice loads these classes reflectively at run time, and the Ice JAR does not declare a dependency on this library. To enable compression, add org.apache.commons:commons-compress to your application's runtime class path, for example with Gradle:

dependencies {
    runtimeOnly "org.apache.commons:commons-compress:1.28.0"
}

When Ice cannot find these classes, it sends all messages uncompressed. If Ice receives a compressed message, it aborts the connection: the sender gets a ConnectionLostException, and the receiver logs a warning when Ice.Warn.Connections is enabled.