jdtContent.setSourceCompatibility(jdtModel.getSourceCompatibility());
        jdtContent.setTargetCompatibility(jdtModel.getTargetCompatibility());
        jdtModel.getFile().getWhenMerged().execute(jdtContent);
    }

    @Override
    protected PropertiesTransformer getTransformer() {
        if (jdt == null) {
            return super.getTransformer();
        }

        //we don't merge anything in the iws, yet.
        //I kept the logic for the sake of consistency
        // and compatibility with pre M4 ways of configuring IDEA information.

        iws.getWhenMerged().execute(xmlWorkspace);
    }

 */
public class FileContentMerger {

    private MutableActionSet whenMerged = new MutableActionSet();
    private MutableActionSet beforeMerged = new MutableActionSet();

    public MutableActionSet getWhenMerged() {
        return whenMerged;
    }

    public void setWhenMerged(MutableActionSet whenMerged) {
        this.whenMerged = whenMerged;
    }

    public MutableActionSet getBeforeMerged() {

    @SuppressWarnings("unchecked")
    public void mergeXmlFacet(WtpFacet xmlFacet) {
        file.getBeforeMerged().execute(xmlFacet);
        xmlFacet.configure(replaceInconsistentFacets(getFacets()));
        file.getWhenMerged().execute(xmlFacet);
    }

        xmlProject.configure(getModules(), getJdkName(), getLanguageLevel(), getTargetBytecodeVersion(), getWildcards(), getProjectLibraries(), getVcs());
        configureModulePaths(xmlProject);
        ipr.getWhenMerged().execute(xmlProject);
    }

    private void configureModulePaths(Project xmlProject) {
        ProjectComponentIdentifier thisProjectId = projectPathRegistry.stateFor(project).getComponentIdentifier();

        new WtpComponentFactory(projectInternal, ideArtifactRegistry, projectRegistry).configure(this, xmlComponent);
        file.getWhenMerged().execute(xmlComponent);
    }

        file.getBeforeMerged().execute(xmlClasspath);
        List<ClasspathEntry> entries = resolveDependencies();
        xmlClasspath.configure(entries);
        file.getWhenMerged().execute(xmlClasspath);
    }

    public FileReferenceFactory getFileReferenceFactory() {
        FileReferenceFactory referenceFactory = new FileReferenceFactory();

        Project decoratedProject = new NonRenamableProject(xmlProject);
        file.getBeforeMerged().execute(decoratedProject);
        xmlProject.configure(this);
        file.getWhenMerged().execute(decoratedProject);
    }

            generatedSourceFolders,
            excludeFolders,
            getInheritOutputDirs(), outputDir, testOutputDir,
            dependencies,
            getJdkName(), level
        );

        iml.getWhenMerged().execute(xmlModule);
    }

    private Set<File> existing(Set<File> files) {
        return Sets.filter(files, new Predicate<File>() {
            @Override
            public boolean apply(File file) {

Method <org.gradle.plugins.ide.api.FileContentMerger.getWhenMerged()> has arguments/return type org.gradle.internal.MutableActionSet that is not Gradle public API or primitive or built-in JDK classes or Kotlin classes in (FileContentMerger.java:0)