HowTo create an ImageJ plugin jar file: Pitfalls and Tips
Brief documentation on how to create an ImageJ jar file plugin.
I recently created my first ImageJ plugin, and wanted to make it a jar file. Seemingly easy, I did not find any documentation on the exact process, which cost me nearly 2 hours and a trip to the ImageJ source code! In an effort to make life easier for you, gentle reader, I've documented some of the pitfalls.
- Plugins can go in the default package or a class with a package declaration.
- Be sure to include an '_' in the filename of the jar file! This is apparently undocumented but very important.
- Create a 'plugins.config' file as part of your jar. This tells ImageJ where to locate your plugin in it's menus.
- The whitespace separating each element in a line must be a space (\s) character and not a tab (\t).
The plugins.config has a format like this:
# This is a comment # Each entry is menuname, "Command text", classname # This puts a command named "Foo" in the Plugins menu associated # with the "FancyPluginClass" class in the default package. Plugins, "Foo", FancyPluginClass #This puts a command named "Foo" in the Plugins>Moo menu associated with the "FooClass" class. Plugins>Moo, "Foo", FooClass #This puts a command named "Left" in the Plugins>Feet menu associated with the org.foo.LeftFootClass class Plugins>Feet, "Left", org.foo.LeftFootClass #This puts a separator between menu items Plugins>Feet, "-" #This puts a command named "Right" in the Plugins>Feet menu associated with the org.foo.RightFootClass class Plugins>Feet, "Right", org.foo.RightFootClass
plugins.config file pitfall
For each line, there should be no space after the class name. For example:
File>New, "Blob1", my.test.Test1 File>New, "Blob2", my.test.Test2
These two lines might look same, but the first one works and the second not. This is because there is a space in the second line after my.test.Test2. It compiles Ok, but in runtime there will be an error message:
Plugin of class not found: “my.test.Test2”
Which will then be a bug that is very difficult to debug. Check the trailing space first!
- JAR Plugin demo documentation There is information on how to package plugins in JAR files in the JAR Plugin demo at:
- Jar File naming The jar file itself must have an underscore in it, otherwise it won't be registered!
- Plugin Architecture
- detailed explanation on the architecture of plugin in Fiji site.
I hope this howto saves you all some time!