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logo Java Settlers

A desktop client-server version of Settlers of Catan


JSettlers is a Java version of the board game Settlers of Catan written in Java. This client-server system supports multiple simultaneous games between people and computer-controlled opponents. Initially created as an AI research project.

The client can host a server, connect to dedicated JSettlers servers over the net, or play practice games offline against bots.

The server can optionally use a database to store player account information and game stats (details below). A client java app to create user accounts is also provided.

If you're upgrading from an earlier version of JSettlers: Check doc/ for new features, bug fixes, and config changes, then see Upgrading from an earlier version section of this Readme.

JSettlers is an open-source project licensed under the GPL. The project is hosted at and . Questions, bugs, patches, and pull requests can be posted at the github page.

- The JSettlers Development Team


  • Screenshots
  • Documentation
  • Requirements
  • Client Command Line
  • Server Setup and Testing
  • Shutting down the server
  • Installing a JSettlers Server
  • Upgrading from an earlier version
  • Security and Admin Users
  • Development and Building JSettlers


New Game options:
New Game options

Classic 4-player board:
Classic 4-player board

Classic 6-player board:
Classic 6-player board

Sea board: Cloth Villages scenario:
Sea board with scenario


User documentation for game play is available as .html pages located in the src/site/users directory. These can be put on a web server for its users to access with a browser.

Currently, this Readme and the doc directory are the only technical documentation for running the client or server, setup and other issues. Over time, more docs will be written. If you are interested in helping write documentation please contact the development team from our github page.

If you downloaded a JSettlers JAR file without attached documentation, the official location of this Readme and the docs is online at .


To play JSettlers you will need either Java Runtime (JRE) version 8 from , or the Java Development Kit (JDK) version 8 or higher from .

Then download JSettlers-full.jar from either or and run it.

To host a JSettlers server, use any server OS and hosting provider you like. To also provide a download for the full Jar, you will need any web server such as nginx or Apache httpd.

The JSettlers-full.jar file can also run locally as a server, without needing a web server. If you're running a LAN game for friends, that Jar is all you need.

To build JSettlers from source, you will need Java JDK 8 or higher, and either gradle 5.6 or higher, or an IDE such as Eclipse which understands gradle's format. See doc/ for details.

Client Command Line

Running the client with no parameters is the same as double-clicking it:
java -jar JSettlers-full.jar will bring up a window with options to connect to a server, practice against bots (no network needed), or start a server for others to connect to.

To connect directly to a server, give its host and port number:
java -jar JSettlers-full.jar 8880

If your screen is High-DPI, JSettlers should automatically detect that instead of running in a very small window. If detection fails for some reason, ask for High-DPI support this way:
java -Djsettlers.uiScale=2 -jar JSettlers-full.jar

Also available: --help, --version, and various debugging flags listed in doc/

Server Setup and Testing

From the command line, make sure you are in the JSettlers distribution directory which contains both JSettlers.jar, JsettlersServer.jar and the lib directory. (If you have downloaded jsettlers-2.x.xx-full.tar.gz, look in the /target directory for these files.)

If you have downloaded jsettlers-2.x.xx-full.jar or jsettlers-2.x.xx-server.jar instead of the full tar.gz, use that filename on the command lines shown below.

Server Startup

Start the server with the following command (server requires Java JDK 8 or higher, or JRE version 8):

java -jar JSettlersServer.jar

This will start the server on the default port of 8880 with 7 robots. It will try to connect to an optional mysql database named socdata; startup will continue even if there is no DB or the DB connect doesn't work.

You can change those values and specify game option defaults; see details below.

If MySQL or another database is not installed and running (See "Database Setup" in doc/, you will see a warning with the appropriate explanation:

Warning: No user database available: ....
Users will not be authenticated.

The database is not required: Without it, the server will function normally except that user accounts cannot be maintained.

If you do use the database, you can give users a nickname and password to use when they log in and play. People without accounts can still connect, by leaving the password field blank, as long as they aren't using a nickname which has a password in the database. Optionally game results and stats can also be saved in the database, see next section; those aren't saved by default.

Parameters and game option defaults:

JSettlers options, parameters, and game option defaults can be specified on the command line, or in a file in the current directory when you start the server.

Command line example:

java -jar JSettlersServer.jar -Djsettlers.startrobots=9 8880 50

In this example the parameters are: Start 9 bots; TCP port number 8880; max clients 50.

The started robots count against your max simultaneous connections (50 in this example). If the robots leave less than 6 player connections available, or if they take more than half the max connections, a warning message is printed at startup. To start a server with no robots (human players only), use


Any command-line switches and options go before the port number if specified on the command line. If the command includes -jar, switches and options go after the jar filename.

To change a Game Option from its default, for example to activate the house rule "Robber can't return to the desert" and set default Victory Points to Win to 13, use -o switches with the game options' names and values, or equivalently "-Djsettlers.gameopt." + the names and values:

-o RD=t -o VP=t13
-Djsettlers.gameopt.RD=t -Djsettlers.gameopt.VP=t13

If a default VP is set, that will also be the minimum winning VP for any scenario. Some scenarios like Cloth Trade may have a higher VP amount, but none will be lower. To use the default VP in all scenarios, even those specifying a higher VP amount, also set game option _VP_ALL=t when starting the server.

You could also set a default game scenario this way; for example if your server was running a tournament of Fog Islands games:


If the scenario's game options conflict with any other game options given, a warning will be printed during startup. In general, servers shouldn't set a default scenario; users can choose a scenario on their own if they want.

To have all completed games' results saved in the database, use this option:

To see a list of all jsettlers options (use them with -D), run:

java -jar JSettlersServer.jar --help

This will print all server options, and all Game Option default values. Note the format of those default values: Some options need both a true/false flag and a numeric value. To change the default winning Victory Points to 12 for example:

-o VP=t12

Savegame optional feature:

The server can save/load most games to files kept on the server, using admin commands. For details see doc/ Search for "Saving and loading games"

Instead of a long command line, any option can be added to which is read at startup if it exists in the current directory. Any option given on the command line overrides the same option in the properties file. Comment lines start with # . See src/main/bin/ for full descriptions of all available properties. (Also available online at

This example command line

java -jar JSettlersServer.jar -Djsettlers.startrobots=9 -o RD=t 8880 50 socuser socpass

is the same as with these contents:

# db user and pass are optional

To determine if the server is reading the properties file, look for this text near the start of the console output:

Reading startup properties from

To check the syntax and values of a file, use the -t or --test-config command line parameter for Config Validation Mode:

java -jar JSettlersServer.jar --test-config

This will test and print all configured values and then exit with return code 0 if no problems are found, nonzero otherwise. Output will include a summary line such as:

* Config Validation Mode: No problems found.

Connect a client

Now, double-click JSettlers.jar to launch the client. If you'd prefer to start the player client from another command line window, use the following command:

java -jar JSettlers.jar

Optionally you can also provide the server's name and port, to skip the Connect To Server dialog:

java -jar JSettlers.jar localhost 8880

When the client launches, click Connect To Server. Leave the Server name field blank to connect to your own computer (localhost) and use the JSettlers server you started up in the previous section.

Once you've connected, enter any name in the Nickname field and create a new game.

Type *STATS* into the chat part of the game window. You should see something like the following in the chat display:

* > Uptime: 0:0:26
* > Total connections: 1
* > Current connections: 1
* > Total Users: 1
* > Games started: 0
* > Games finished: 0
* > Total Memory: 2031616
* > Free Memory: 1524112
* > Version: 1100 (1.1.00) build JM20080808

Now click on the "Sit Here" button and press "Start Game". The robot players should automatically join the game and start playing.

To play again with the same game options and players, click "Quit", then "Reset Board". If other people are in the game, they will be asked to vote on the reset; any player can reject it. If bots are in your game, and you want to reset with fewer or no bots, click the bot's Lock button before clicking Quit/Reset and it won't rejoin the reset game.

If you want other people to access your server, tell them your server address and port number (the default is 8880). They can run the JSettlers.jar file by itself, and it will bring up a window to enter your server address (DNS name or IP) and port number. Or, they can enter the following command:

java -jar JSettlers.jar <server_address> <port_number>

If you would like to maintain accounts for your JSettlers server, start the database prior to starting the JSettlers Server. See the "Database Setup" section of doc/ for directions.

Server shutdown

To shut down the server hit Ctrl-C in its console window, or connect as the optional debug user and enter *STOP* in the chat area of a game window. This will stop the server and all connected clients will be disconnected. (See doc/ if you want to set up a debug user.)

Installing a JSettlers server


  • If using the optional database, start MariaDB, MySQL, or PostgreSQL server
    (file-based sqlite is another lightweight DB option)
  • Copy and edit (optional)
  • Start JSettlers Server
  • Start web server (optional)
  • Copy JSettlers.jar client JAR and src/site/*.html to a web-served directory (optional)


If you want to maintain user accounts or save scores of all completed games, all of which is optional, you will need to set up a MariaDB, MySQL, PostgreSQL, or SQLite database. If you will be using a non-SQLite database, be sure to start the database server software before installing JSettlers. For DB setup details see the "Database Setup" section of doc/ (available online at

To install a JSettlers server, start the server as described in "Server Setup and Testing". Remember that you can set server parameters and game option default values with a file: Copy the sample file src/main/bin/ to the same directory as JSettlersServer.jar, rename it to, and edit properties as needed. For more details see the section of this Readme.

Remote users can simply start their clients as described there, and connect to your server's DNS name or IP address.

To provide a web page where players can download the Jar, you will need to set up a web server such as nginx or Apache. Alternately, have them download the full Jar from .

If setting up a web server: We assume you have installed the web server software already, and will refer to ${docroot} as a directory to place files to be served by your web server.

Copy index.html from src/site/ to ${docroot}. If you're going to use an accounts database and anyone can register their own account (this is not the default setting), also copy accounts.html.

Edit the html to make sure the port number mentioned in index.html and account.html matches the port of your JSettlers server, and the text starting "Connect to" has the right server name. If you're using account.html, also un-comment index.html's link to account.html.

Next copy the JSettlers.jar full client file to ${docroot}. This will allow users to download it to connect from their computer. (If you've downloaded it as JSettlers-{version}-full.jar, rename it to JSettlers.jar.)

Your web server directory structure should now contain:

${docroot}/account.html (optional)

Users should now be able to visit your web site to download the JSettlers client.

Upgrading from an earlier version

If you're doing a new installation, not upgrading a server that's already been running JSettlers, skip this section.

It's a simple process to upgrade to the latest version of JSettlers:

  • Read this readme's "Requirements" section, in case the minimum java version or another requirement has changed
  • Read doc/ for new features, bug fixes, and config changes made from your version to the latest version. Occasionally defaults change and you'll need to add a server config option to keep the same behavior, so read carefully.
  • If using the applet: When upgrading from 1.x to 2.x, the applet class name changes from soc.client.SOCPlayerClient to soc.client.SOCApplet, so update the applet tag in your download page html. (Most people and most browsers don't use the applet anymore.)
  • If you're using the optional database, backup the database and see the "Upgrading from an earlier version" section of doc/ for parameter changes and other actions to take.
  • Save a backup copy of your current JSettlers.jar and JSettlersServer.jar, in case you want to run the old version for any reason.
  • Stop the old server
  • Copy the new JSettlers.jar and JSettlersServer.jar into place
  • Start the new server, including any new options you wanted from doc/
  • If the new server's startup messages include a line about database schema upgrade, see the "Upgrading" section of doc/
  • Test that you can connect and start games as usual, with and without bots. When you connect make sure the version number shown in the left side of the client window is the new JSettlers version.

Security and Admin Users

The server has commands anyone can run by typing into a game's chat window, like *STATS* or *WHO*. It also has privileged commands that can be run only by named Admin Users or the debug user, like *GC* or *SAVEGAME*.

The debug user shouldn't be enabled except on a developer's own computer, because of its in-game abilities. Admin Users let you manage your server without the debug user. They authenticate with passwords stored in a SQLite file or a database system. To set up Admin Users, see section "Security, Admin Users, Admin Commands" of doc/

JSettlers does not use log4j, and all released versions are not vulnerable to CVE-2021-44228.

Development and Building JSettlers

JSettlers is an open-source project licensed under the GPL. The project source code is hosted at and the project website is . Questions, bugs, patches, and pull requests can be posted at the github page.

For more information on building or developing JSettlers, see doc/ That readme also has information about translating jsettlers to other languages; see the "I18N" section.

JSettlers is licensed under the GNU General Public License. Each source file lists contributors by year. A copyright year range (for example, 2007-2011) means the file was contributed to by that person in each year of that range. See individual source files for the GPL version and other details.

The localization into French was contributed in 2020 by Lee Passey using the CC0 license, and further developed by Jeremy Monin under CC0. is licensed under the "new BSD" license, and is copyright (C) 2006 Damien Miller; see for details. jBCrypt-0.4.tar.gz retrieved 2017-05-27 from and some constants, javadocs, throws declarations added by Jeremy D Monin.

org.fedorahosted.tennera.antgettext.StringUtil is licensed under the "Lesser GPL" (LGPL) license, and is from the JBoss Ant-Gettext utilities.

Miscellaneous code is attributed to the Strategic Conversation (STAC) Project - - from their fork published at and reintegrated into JSettlers by Jeremy D Monin for v2.5.00. The StacSettlers readme says "Copyright (C) 2017 STAC" and that repo's most recent substantial change was in 2018. In the JSettlers repository, commits from that code use "STAC Project" as the author.

The classic hex and port images were created by Jeremy Monin, and are licensed Creative Commons Attribution Share Alike (cc-by-sa 3.0 US) or Creative Commons Attribution (CC-BY 3.0 US); see each image's gif comments for details. classic/goldHex.gif is based on a 2010-12-21 CC-BY 2.0 image by Xuan Che, available at , of ancient Greek coins.

The pastel hex images were created and contributed by qubodup, (C) 2019, licensed CC-BY-SA 3.0, and were retrieved 2019-08-17 from (rendered with that repo's script).

doc/graf/Logo.svg was created and contributed by Ruud Poutsma, (C) 2017.

SourceForge Community Choice Award badge This project is a SourceForge Community Choice Award winner (March 2022).


Java Settlers project home, downloads, and GPLv3 source code. To download the latest version as a JAR, see .







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