Frequented Asked Questions

General

I'm behind a firewall that prevent to access to Maven Central, what can I do ?

If you cannot access to Maven Central repository for whatever reason, you should use a Maven repository that is accessible from your organisation.

This section explains how you can setup the upload repository globally or for a given project.

Alternatively, you can define the JEKA_REPOS_DOWNLOAD environment variable.

See here for more details.

I'm behind a proxy, how should I configure Jeka ?

JeKa just leverages the standard Java mechanism to handle proxy. For example, You can :

• Set the JAVA_TOOL_OPTIONS environment variable as -Dhttps.proxyHost=my.proxy.host -Dhttps.proxyPort=8888
• Or specify proxy properties to the jeka command line, as : -Dhttps.proxyHost=my.proxy.host -Dhttps.proxyPort=8888

See here for more details on arguments.

How can I use Maven/Gradle in conjunction with JeKa ?

Nothing prevents to use JeKa in conjunction of Maven or Gradle in the same project, except that in IDE, synchronisation may interfere between the 2 systems.

To avoid that, JeKa proposes a simple solution. In your existing Maven/Gradle project do :

1. Execute : jeka base: scaffold. This generates the folder/file structure for JeKa
2. Execute jeka intellij: jekaSrcAsModule in root dir

This will add a property @intellij.imlFile=jeka-src/.idea/jeka-src.iml in your jeka.properties file.

Note

'jeka-src' should now live in its own Intellij module. If your IDE does not reflect this state, just close and re-open the project.

Now jeka-src live in its own IntelliJ module. Simply execute jeka intellij: imlto sync JeKa without impacting Maven/Gradle.

Warning

Do not remove the @intellij.imlFile=jeka-src/.idea/jeka-src.iml property from jeka.property file, otherwise you will still face sync issues.

How can I migrate my project from Maven ?

JeKa helps translating all dependencies declared in a Maven project into the equivalent Java code.

Assuming Maven is already installed and there is a pom.xml file at the root of the project, execute jeka maven: showPomDeps to display Java code/configuration to copy-paste in a build class or dependencies.txt file.

How to cache downloaded dependencies in Github-actions ?

JeKa caches downloaded dependencies (JDKs, JeKa distros, Maven artifacts, NodeJs exe,...) in a single directory at [USER HOME]/.jeka/cache.

When running as Github Action this directory is empty at the start of the build. We need to save/restore it in order to make it persist from one build to another.

For this, we can use cache action as follow:

    - name: Restore JeKa cache
      uses: actions/cache/restore@v4
      with:
        path: ~/.jeka/cache
        key: ${{ runner.os }}

    - name: Run some JeKa commands
      run: "./jeka project: pack ..."

    - name: Save JeKa cache
      uses: actions/cache/save@v4
      with:
        path: ~/.jeka/cache
        key: ${{ runner.os }}

Compilation

How can I use Eclipse compiler in Jeka ?

Jeka can use any JSR199 Java compiler to compile your Java code. Just set the compiler instance you need as :

import org.eclipse.jdt.internal.compiler.tool.EclipseCompiler;

@JkInjectClasspath("org.eclipse.jdt.core.compiler:ecj:4.6.1")
public class Build extends JkBean {

    ...
    project.compilerToolChain.setCompileTool(new EclipseCompiler());
}

How can I sync Eclipse/Intellij without using ProjectKBean ?

ProjectKBean KBean provides IDE sync out-of-the-box but you may prefer to not use it.

Just let your KBean implements JkJavaIdeSupport and implement the unique method that is proving info necessary to generate IDE metadata file.

Then, for sync, just execute jeka intellij: iml as usual.