This page describes how to compile the Java source code in order to get a runnable `josm-custom.jar` file.

== Getting the Source ==
→ [[Download#Source]]

== Compiling using `ant` ==
The easiest way to compile JOSM, provided [https://www.java.com/en/download/faq/develop.xml Java JDK] and [https://ant.apache.org/ Ant] on your machine are properly set up, is to go to the josm directory and type:

{{{
#!sh
ant
}}}

That will create a `dist/josm-custom.jar` file if successful.

== Compiling using eclipse ==

Use eclipse and the provided `.project` and `.classpath` file. Just add a new Java Project using the JOSM source folder as existing path.

As of Eclipse 3.5.2 and the latest JOSM (August 10, 2011), you will have problems compiling, due to problems compiling Mappaint MapCSS with a fresh install of Eclipse. First you will need the [http://www.engr.mun.ca/~theo/JavaCC-FAQ/javacc-faq-moz.htm JavaCC] [http://eclipse-javacc.sourceforge.net/ plugin for Eclipse]. To install it in Eclipse, go to Help->New Software... then add the site [http://eclipse-javacc.sourceforge.net/] as a source, and install the JavaCC Eclipse Plug-in. Then in the Package Explorer, expand org.openstreetmap.josm.gui.mappaint.mapcss, right-click on MapCSSParser.jj, and "Compile with JavaCC". This should put new java files in a package called org.openstreetmap.josm.gui.mappaint.mapcss.parsergen, but if it doesn't, you will have to create the package manually (right-click and create package), then drag the new files into the package you just created (they should be easy to identify based on the light gray text that denotes it was compiled from MapCSSParser.jj). This should resolve any import issues in MapCSSStyleSource.java, and you should now be able to compile JOSM.

If you try to compile the JOSM sources in Eclipse and get errors like "The method marktr(String) is undefined for the type SomeType" look at [https://lists.openstreetmap.org/pipermail/josm-dev/2008-August/001585.html solution suggested at mailing list].

There are also two Videos available at youtube, which show [https://www.youtube.com/watch?v=-LoWGf-hqiQ how to checkout JOSM into Eclipse] and [https://www.youtube.com/watch?v=Z3OjG3nDvzA how to checkout a JOSM plugin into Eclipse].

== Unit Tests ==

It is most convenient, to run tests from an IDE like Eclipse or Netbeans. There is also an ant task to run all tests (but you cannot rerun individual tests).

All unit tests can be run in headless mode (i.e, without a graphic display), allowing them to be run in continuous integration projects.

=== Running Test from Command line ===

You can run tests from the command line, as well. Include all libraries in the class path like this:
{{{
#!sh
export TESTCP=".:test/unit:test/functional:dist/josm-custom.jar:test/lib/fest/fest-assert-1.0.jar:test/lib/fest/MRJToolkitStubs-1.0.jar:test/lib/fest/jcip-annotations-1.0.jar:test/lib/fest/fest-swing-1.1.jar:test/lib/fest/fest-reflect-1.1.jar:test/lib/fest/fest-util-1.0.jar:test/lib/fest/debug-1.0.jar:test/lib/junit/junit-4.11.jar:test/lib/jfcunit.jar:test/lib/unitils-core/ognl-2.6.9.jar:test/lib/unitils-core/commons-lang-2.3.jar:test/lib/unitils-core/unitils-core-3.3.jar:test/lib/unitils-core/commons-logging-1.1.jar:test/lib/unitils-core/commons-collections-3.2.jar"
}}}
Then run for example
{{{
#!sh
javac -cp $TESTCP test/unit/org/openstreetmap/josm/data/projection/ProjectionRefTest.java
java -cp $TESTCP org.junit.runner.JUnitCore org.openstreetmap.josm.data.projection.ProjectionRefTest
}}}