This page explains how to create a patch, modify the core JOSM application or existing plugins.
At least basic Java programming skills are necessary. See WikiStart how you could improve JOSM without Java skills.
Source code and JOSM builds
- Installing and Running JOSM
- Source code#Getthesource
- Source code#CompilingusingAnt
- Compiling JOSM using IDE
- Development Guidelines (Coding style and Internationalization)
- Default Presets (about new osm-tags and icons in JOSM)
- Patch Guidelines (How to submit a patch)
- Track the state of development (Release Schedule)
- Ticket system guidelines
- Various Eclipse tips
- Video: how to checkout JOSM into Eclipse
- Video: how to checkout a JOSM plugin into Eclipse
JOSM core developers are using the YourKit Java Profiler, as we found other tools lacking required functionality for profiling. YourKit supports open source projects by granting developers free licenses.
To enable the YourKit Java agent, add the following JVM parameter:
VisualVM may be used to find memory leaks or generate heap dumps from a josm instance running concurrently. Heap dumps can be structurally examined. VisualVM organizes the dump data e.g. by number and type of objects, memory used and cpu time consumed in an explorable tree view. Heap dump and garbage collection of the target instance is requestable using button clicks. Be aware that the default configuration of the memory sampler will sample VisualVM generated objects as well, which may be confused as a memory leak. The memory profiler can be set to profile specific classes only, it tracks allocations once started.
If an autonomous instance of josm should be debuggable from within eclipse at the same time, command line parameters must be supplied to open a transport socket that the debugger can connect to:
# run JOSM with remote debug options; connect a debugger to 127.0.0.1 and port 9988 java -agentlib:jdwp=transport=dt_socket,address=127.0.0.1:9988,server=y,suspend=n -Xmx1200m -jar josm-latest.jar
This is not necessary if the internals of JOSM are to be explored by VisualVM exclusively.
- SVN: How to use your JOSM SVN account
- Help: Current list of topics as targets for the Context-sensitive help
- Shortcuts: Current list of shortcut keys
- Translation: for program and Wiki and Presets
- Sandbox: OSM data sandbox
- Salt Formula: https://github.com/saltstack-formulas/josm-formula
Dirk Stöcker is currently the lead maintainer of JOSM. Developers of JOSM with SVN commit privileges active in the past several months include:
Immanuel Scholz was the original creator of JOSM, and previous maintainers include Frederik Ramm.
Many others have contributed through bug reports, patches, translations, and documentation work.