Configuring VSCode for ICU4J

To get ICU4J running in VSCode, including JUnit support:

1. Install the Extension Pack for Java (vscjava.vscode-java-pack)
2. In settings.json, remove the contents of "java.project.resourceFilters". This will prevent the extension from dirtying your .project files in later steps:

    "java.project.resourceFilters": [
    ]

3. Run ant init in the icu4j directory

4. Create a new workspace and add each of the following directories to it:

   • icu4j/main/classes/* (all directories at that path)
   • icu4j/main/tests/* (all directories at that path)
   • icu4j/tools/misc

5. Modify all of the icu4j/main/tests/.classpath files as follows:

   1. Change all occurrences of /external-libraries/ to ../../../lib/.
   2. Add classpathentrys for the data jar files.

   For example:

<!-- Before -->

	<classpathentry kind="lib" path="/external-libraries/hamcrest-core-1.3.jar"/>
	<classpathentry kind="lib" path="/external-libraries/junit-4.12.jar" sourcepath="/external-libraries/junit-4.12-sources.jar">
		<attributes>
			<attribute name="javadoc_location" value="jar:platform:/resource/external-libraries/junit-4.12-javadoc.jar!/"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="lib" path="/external-libraries/JUnitParams-1.0.5.jar" sourcepath="/external-libraries/JUnitParams-1.0.5-sources.jar">
		<attributes>
			<attribute name="javadoc_location" value="jar:platform:/resource/external-libraries/JUnitParams-1.0.5-javadoc.jar!/"/>
		</attributes>
	</classpathentry>

<!-- After -->

	<classpathentry kind="lib" path="../../../lib/hamcrest-core-1.3.jar"/>
	<classpathentry kind="lib" path="../../../lib/junit-4.12.jar" sourcepath="../../../lib/junit-4.12-sources.jar">
		<attributes>
			<attribute name="javadoc_location" value="jar:platform:/resource/../../../lib/junit-4.12-javadoc.jar!/"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="lib" path="../../../lib/JUnitParams-1.0.5.jar" sourcepath="../../../lib/JUnitParams-1.0.5-sources.jar">
		<attributes>
			<attribute name="javadoc_location" value="jar:platform:/resource/../../../lib/JUnitParams-1.0.5-javadoc.jar!/"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="lib" path="../../shared/data/icudata.jar"/>
	<classpathentry kind="lib" path="../../shared/data/icutzdata.jar"/>
	<classpathentry kind="lib" path="../../shared/data/testdata.jar"/>

6. To prevent your changes to .classpath from accidentally being committed, you can run:

$ git update-index --assume-unchanged main/tests/*/.classpath

7. If VSCode also tries changing your org.eclipse.jdt.core.prefs files, you can ignore those, too:

$ git update-index --assume-unchanged main/classes/*/.settings/org.eclipse.jdt.core.prefs
$ git update-index --assume-unchanged main/tests/*/.settings/org.eclipse.jdt.core.prefs
$ git update-index --assume-unchanged tools/misc/.settings/org.eclipse.jdt.core.prefs

8. To verify that everything is working, use the VSCode UI to run your choice of JUnit test. Open any *.java file, and you should see a double-right triangle, which you can click to run the test.

Other tips:

• View the project outline under “Java Projects” on the left side under the file explorer; from here, you can rebuild projects, run all tests, add new classes, etc.
• To rebuild: open the command palette (Shift + Ctrl + P on Linux) and search for “Java: Rebuild Projects”
• To debug: right-click the icon where you run your test, and click “Debug Test”