How to use installed plugin in a java project in Eclipse? - eclipse-plugin

Question

I have created one java project with 'project_p' with three packages a, b and c.
In package 'a', I have class 'A', method 'action' which prints: "inside class A". In package b, class B, method 'boxing' which prints: "inside class B". In package 'c', class 'C', method 'catching' - this prints: "inside class C" and also calls 'action' and 'boxing'. There is no main method in any class.
project_p
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src
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-> a --> class A --> method action --> System.out.println("inside class A.");
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-> b --> class B --> method boxing --> System.out.println("inside class B.");
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-> c --> class C --> method catching --> System.out.println("inside class C.");
A aobj = new A();
aobj.action();
B.boxing();
Then, I created a jar of 'project_p' with all the three packages.
Used that jar to create a plugin 'project_plugin', created the feature 'project_plugin_feature' and update site 'project_plugin_site' for the plugin.
Then installed that plugin to Eclipse using Help --> Install new software.
Now, I have created another java project 'project_plugin_usage' with one package 'abc', class ABC. There is one main method inside class ABC.
My question is - How can I use that installed plugin in the project 'project_plugin_usage' so that I could call method 'action', 'boxing', and 'catching' in the main method of 'project_plugin_usage'?

Answer 1

A plain Java project cannot use code in a plug-in. Only another plug-in can access the code.
For plug-ins: the plug-in providing the code must declare the packages that it makes available in a Export-Package statement in its MANIFEST.MF.
For example:
Export-Package: greg.music.core.autoclose,
greg.music.core.bool
exports two packages.
If the plug-in wants to export packages from a jar included in the plug-in it must include the jar in the Bundle-ClassPath in the MANIFEST.MF
The plug-in which wants to use the packages must add the source plug-in to the Require-Bundle statement in its MANIFEST.MF
Require-Bundle: pluginid