Simple Java Swing based tennis (ping-pong-style)

This is a simple demo with an optional RMI based gaming server.

Back in 2003 it started as a learning project under Java 5 with an Apache Ant build.xml. Later I added an Apache Maven pom.xml and now it also supports a Gradle build.gradle build.

• Java 17 or later (required by Gradle 9.2.0)
• Gradle wrapper included (gradlew)

• Java 8 or later (the compiled JAR is Java 8 compatible)

Note: While the project compiles to Java 8 bytecode (source/target compatibility 1.8), you need Java 17+ installed to run the Gradle build process.

./gradlew build

This will:

• Compile all Java sources
• Run unit tests
• Create a fat JAR file in build/libs/tennis-1.0.0-SNAPSHOT.jar (includes all dependencies)

mvn clean package

ant compile
ant jar

Play tennis with two players on the same computer using keyboard controls.

Using the JAR file:

./gradlew jar
java -jar build/libs/tennis-1.0.0-SNAPSHOT.jar

The JAR file is a "fat JAR" that includes all dependencies (TableLayout, SLF4J, Logback), so it can be run standalone.

How to play:

1. Select Game → Login from the menu
2. Enter a player name
3. Use keyboard controls:
   • Player 1: Arrow keys (↑/↓/←/→)
   • Player 2: Page Up/Page Down/F1/F2

Play tennis over the network using Java RMI.

On the server machine:

./gradlew jar
java -cp build/libs/tennis-1.0.0-SNAPSHOT.jar de.sepe.tennis.remote.server.ServerImpl

(Note: Use -cp not -jar since we need to specify the main class)

You should see:

RMI registry created on port 1099
tennisServer bound in registry
Server ready and waiting for connections...
Press Ctrl+C to stop.

The server will:

• Create an RMI registry on port 1099
• Bind the tennis server as "tennisServer"
• Keep running until you press Ctrl+C

On the client machine(s):

./gradlew jar
java -cp build/libs/tennis-1.0.0-SNAPSHOT.jar de.sepe.tennis.remote.gui.Tennis

Note: If the server is on a different machine, you'll need to update the hardcoded localhost reference in Court.java:166 to point to the server's IP address or hostname.

The project contains two separate implementations:

• Single-machine game
• Two players share one keyboard
• All game logic runs locally
• Classes: Tennis, Court, Player, Ball, Controller

• Network-based multiplayer using Java RMI
• Server manages game sessions
• Clients connect to play
• Classes:
  • Server: ServerImpl, Session, Player, Ball
  • Client: Tennis, Court, PlayerView, BallView
  • Interfaces: Server (RMI remote interface)

If you see Connection refused to host errors:

• Make sure the server is running first
• Check that a firewall does not block port 1099
• The server creates its own RMI registry, so you don't need to run rmiregistry separately

This is fixed in the current version. The server creates the RMI registry in the same JVM, ensuring all classes are available.

Note: RMI stub classes are generated dynamically at runtime (since Java 5), so no explicit stub generation step is needed.

The project supports three build systems for historical reasons:

• Gradle (build.gradle) - Recommended, most modern
• Maven (pom.xml) - Alternative build system
• Ant (build.xml) - Legacy build system from 2003

All three should produce equivalent results.

Copyright © 2003 Sebastian Peters. All Rights Reserved.