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Getting OpenTripPlanner

Pre-built JARs

OpenTripPlanner is distributed as a single stand-alone runnable JAR file. We create a tag and release page on GitHub for each release version, and also deploy them to the Maven Central repository. You can go to the release pages on GitHub or the OTP directory at Maven Central, navigate to the highest version number, and download the file whose name ends with shaded.jar.

Note that version numbers like v2.1.0-rc1 or v2.4.0-SNAPSHOT refer to development builds _ before_ the release version v2.4.0. The existence of a build vX.Y.Z-SNAPSHOT does not mean that vX.Y.Z has been released yet.

We use the Github Actions CI system to build OTP every time a change is made. You can find the JARs resulting from those builds in the Github Packages repository . It can be harder to find the specific version you're looking for here, so we recommend using the release pages or Maven Central as described above.

Building from Source

You may also choose to build OTP from its source code. If you will be modifying OTP you will need to know how to rebuild it (though your IDE may take care of this build cycle for you). If you have the right software installed, building OTP locally from its source code is not particularly difficult. You should only need the following software:

  • Git, a version control system

  • Java Development Kit, preferably version 21

  • Maven, a build and dependency management system

You will also need a reliable internet connection so Maven can fetch all of OTP's dependencies (the libraries it uses).

Once you have these packages installed, create and/or switch to the directory where you will keep your Git repositories and make a local copy of the OTP source code:

mkdir git
cd git
git clone git@github.com:opentripplanner/OpenTripPlanner.git

Then change to the newly cloned OpenTripPlanner repository directory and start a build:

cd OpenTripPlanner
mvn clean package

Maven should then be able to download all the libraries and other dependencies necessary to compile OTP. If all goes well you should see a success message like the following:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 42.164s
[INFO] Finished at: Tue Feb 18 19:35:48 CET 2014
[INFO] Final Memory: 88M/695M
[INFO] ------------------------------------------------------------------------

This build process should produce a JAR file called otp-x.y.z-shaded.jar in the target/ directory which contains all the compiled OTP classes and their dependencies (the external libraries they use). The shell script called 'otp' in the root of the cloned repository will start the main class of that JAR file under a Java virtual machine, so after the Maven build completes you should be able to run ./otp --help and see an OTP help message including command line options. Due to the way Maven works, this script is not executable by default, so you will need to do chmod u+x ./otp before you run it to mark it as executable.

The words "clean package" are the build steps you want to run. You're telling maven to clean up any extraneous junk in the directory, then perform all the build steps, including compilation, up to and including "package", which bundles the compiled program into a single JAR file for distribution.

If you have just cloned OTP you will be working with the default "master" branch, where most active development occurs. This is not the most stable or deployment-ready code available. To avoid newly minted bugs or undocumented behavior, you can use Git to check out a specific release (tag or branch) of OTP to work with. The Maven build also includes many time-consuming integration tests. When working with a stable release of OTP, you may want to turn them off by adding the switch: -DskipTests.

For example, you could do the following:

cd OpenTripPlanner
git checkout v2.4.0
git clean -df
mvn clean package -DskipTests

Please note that the build process creates two distinct versions of the OTP JAR file. The one ending in -shaded.jar is much bigger because it contains copies of all the external libraries that OTP uses. It serves as a stand-alone runnable distribution of OTP. The one with a version number but without the word shaded contains only OTP itself, without any external dependencies. This JAR is useful when OTP is included as a component in some other project, where we want the dependency management system to gather all the external libraries automatically.

Maven Repository

OpenTripPlanner is a Maven project. Maven is a combined build and dependency management system: it fetches all the external libraries that OTP uses, runs all the commands to compile the OTP source code into runnable form, performs tests, and can then deploy the final "artifact" (the runnable JAR file) to the Maven repository, from which it can be automatically included in other Java projects.

This repository is machine-readable (by Maven or other build systems) and also provides human readable directory listings via HTTP. You can fetch an OTP JAR from this repository by constructing the proper URL for the release you want. For example, release 2.4.0 will be found at https://repo1.maven.org/maven2/org/opentripplanner/otp/2.4.0/otp-2.4.0-shaded.jar.

To make use of OTP in another Maven project, you must specify it as a dependency in that project's pom.xml:

<dependency>
  <groupId>org.opentripplanner</groupId>
  <artifactId>otp</artifactId>
  <version>2.4.0</version>
</dependency>