Added separate Kotlin package trees

CHANGELOG.md

@@ -1,3 +1,4 @@
+- Added separate Java and Kotlin package trees in Project Explorer: conventional `src/main/java` and `src/test/java` remain under **Source Packages** and **Test Packages**, while `src/main/kotlin` and `src/test/kotlin` appear under **Kotlin Source Packages** and **Kotlin Test Packages** in Maven, Gradle, and Ant/J2SE projects.
 - Added Inline Type Alias refactoring: place the caret on a Kotlin `typealias` declaration or one of its type uses, press **Ctrl+Alt+N** or choose **Refactor → Inline...**, then expand every supported Kotlin occurrence or only the selected use and optionally retain the alias declaration; generic arguments, imports, and parenthesisation use the IntelliJ IDEA K2 engine, while **Undo Last Refactoring** restores all changed Kotlin files.
 - Added Change Kotlin Package refactoring: use **Refactor → Change Kotlin Package...** for the active Kotlin file or a folder's recursive Kotlin descendants to update package directives in place; nested files retain their relative package hierarchy, supported Kotlin code references and direct imports update, and **Undo Last Refactoring** restores the original contents.
 - Added Move Kotlin File and Directory refactoring: move the active `.kt` file from **Refactor → Move Kotlin File...**, or right-click a folder and choose **Move Kotlin Directory...** to recursively move its Kotlin files while retaining the selected directory and nested structure below a selected source root/package; matching package directives and supported Kotlin code references are updated, and **Undo Last Refactoring** restores the original locations and contents.

CoreImpl/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-core-impl</artifactId>

KotlinCompilerCliBase/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-compiler-cli-base</artifactId>

KotlinFixesImpl/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-fixes-impl</artifactId>

KotlinFormatter/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-formatter</artifactId>

KotlinHighlighting/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-highlighting</artifactId>

KotlinIcons/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-icons</artifactId>

KotlinIntentionUtils/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-intention-utils</artifactId>

KotlinRefactoring/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-refactoring</artifactId>

Nbm/pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-kotlin</artifactId>
-    <version>0.11.250-SNAPSHOT</version>
+    <version>0.11.252-SNAPSHOT</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
   <artifactId>netbeans-plugin-kotlin-nbm</artifactId>

Nbm/src/main/java/org/jetbrains/kotlin/projectsextensions/gradle/lookup/GradleProjectLookupProviderExtension.java

@@ -34,7 +34,8 @@ public Lookup createAdditionalLookup(Lookup lkp) {
         Project project = lkp.lookup(Project.class);
 
         return Lookups.fixed(new KotlinPrivilegedTemplates(),
-                new GradleProjectOpenedHook(project));
+                new GradleProjectOpenedHook(project),
+                new io.github.nbplugins.kotlin.nbm.projectsextensions.KotlinProjectSources(project));
     }
 
 }

Nbm/src/main/java/org/jetbrains/kotlin/projectsextensions/j2se/lookup/J2SEProjectLookupProviderExtension.java

@@ -39,8 +39,9 @@ public Lookup createAdditionalLookup(Lookup lkp) {
 
         return Lookups.fixed(
                 new KotlinPrivilegedTemplates(),
-                new J2SEExtendedClassPathProvider(j2seProject), 
-                new J2SEProjectOpenedHook(j2seProject)
+                new J2SEExtendedClassPathProvider(j2seProject),
+                new J2SEProjectOpenedHook(j2seProject),
+                new io.github.nbplugins.kotlin.nbm.projectsextensions.KotlinProjectSources(j2seProject)
         );
     }
 

Nbm/src/main/java/org/jetbrains/kotlin/projectsextensions/maven/lookup/MavenProjectLookupProviderExtension.java

@@ -35,7 +35,8 @@ public Lookup createAdditionalLookup(Lookup lkp) {
         Project project = lkp.lookup(Project.class);
 
         return Lookups.fixed(new KotlinPrivilegedTemplates(),
-                new MavenProjectOpenedHook(project)
+                new MavenProjectOpenedHook(project),
+                new io.github.nbplugins.kotlin.nbm.projectsextensions.KotlinProjectSources(project)
         );
     }
 

Nbm/src/main/kotlin/io/github/nbplugins/kotlin/nbm/projectsextensions/FilteredSourceGroup.kt

@@ -0,0 +1,59 @@
+/**
+ * ******************************************************************************
+ * Copyright 2000-2016 JetBrains s.r.o.
+ * Copyright 2026 nbplugins contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ******************************************************************************
+ */
+package io.github.nbplugins.kotlin.nbm.projectsextensions
+
+import java.beans.PropertyChangeListener
+import javax.swing.Icon
+import org.netbeans.api.project.SourceGroup
+import org.openide.filesystems.FileObject
+
+/** Hides [excludedFolders] from a broader Java source group without changing project metadata. */
+class FilteredSourceGroup(
+    private val delegate: SourceGroup,
+    excludedFolders: Collection<FileObject>
+) : SourceGroup {
+    private val excludedPaths = excludedFolders.map(FileObject::getPath).toSet()
+
+    /** Returns the delegated root folder. */
+    override fun getRootFolder(): FileObject = delegate.rootFolder
+
+    /** Returns the delegated stable source-group identifier. */
+    override fun getName(): String = delegate.name
+
+    /** Returns the delegated Project Explorer label. */
+    override fun getDisplayName(): String = delegate.displayName
+
+    /** Returns the delegated icon. */
+    override fun getIcon(opened: Boolean): Icon? = delegate.getIcon(opened)
+
+    /** Returns whether [file] belongs to the Java group and is not a Kotlin root or its descendant. */
+    override fun contains(file: FileObject): Boolean =
+        delegate.contains(file) && excludedPaths.none { path -> file.path == path || file.path.startsWith("$path/") }
+
+    /** Registers [listener] with the delegated group. */
+    override fun addPropertyChangeListener(listener: PropertyChangeListener?) {
+        delegate.addPropertyChangeListener(listener)
+    }
+
+    /** Removes [listener] from the delegated group. */
+    override fun removePropertyChangeListener(listener: PropertyChangeListener?) {
+        delegate.removePropertyChangeListener(listener)
+    }
+}

Nbm/src/main/kotlin/io/github/nbplugins/kotlin/nbm/projectsextensions/KotlinProjectNodeFactories.kt

@@ -0,0 +1,194 @@
+/**
+ * ******************************************************************************
+ * Copyright 2000-2016 JetBrains s.r.o.
+ * Copyright 2026 nbplugins contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * ******************************************************************************
+ */
+package io.github.nbplugins.kotlin.nbm.projectsextensions
+
+import javax.swing.event.ChangeEvent
+import javax.swing.event.ChangeListener
+import org.netbeans.api.java.project.JavaProjectConstants
+import org.netbeans.api.project.Project
+import org.netbeans.api.project.ProjectUtils
+import org.netbeans.api.project.SourceGroup
+import org.netbeans.api.project.Sources
+import org.netbeans.spi.java.project.support.ui.PackageView
+import org.netbeans.spi.project.ui.support.NodeFactory
+import org.netbeans.spi.project.ui.support.NodeList
+import org.openide.nodes.Node
+import org.openide.util.ChangeSupport
+import org.openide.util.RequestProcessor
+
+/**
+ * Adds dedicated Kotlin main and test package nodes to project types whose standard
+ * node factory already renders Java source groups.
+ */
+class KotlinProjectNodeFactory : NodeFactory {
+
+    /**
+     * Creates the Kotlin package-node list for [project].
+     *
+     * @param project project being rendered in Project Explorer
+     * @return dynamic list of Kotlin source-root nodes
+     */
+    override fun createNodes(project: Project): NodeList<SourceGroup> =
+        KotlinSourceNodeList(project, includeJavaGroups = false, includeGradleOtherGroups = false, filterJavaKotlinRoots = false)
+}
+
+/** Supplies the missing source nodes for the legacy third-party Gradle integration. */
+class KotlinLegacyGradleProjectNodeFactory : NodeFactory {
+
+    /**
+     * Creates a source list for the legacy Gradle project type.
+     *
+     * @param project legacy Gradle project being rendered in Project Explorer
+     * @return Kotlin package-tree nodes for the project
+     */
+    override fun createNodes(project: Project): NodeList<SourceGroup> =
+        KotlinSourceNodeList(project, includeJavaGroups = true, includeGradleOtherGroups = false, filterJavaKotlinRoots = true)
+}
+
+/**
+ * Replaces the built-in Gradle source node factory, which otherwise merges Java and Kotlin trees.
+ */
+class KotlinGradleProjectNodeFactory : NodeFactory {
+
+    /**
+     * Creates a source list that preserves Java, resource, and generated nodes while splitting Kotlin.
+     *
+     * @param project Gradle project being rendered in Project Explorer
+     * @return dynamic list of Gradle source-root nodes
+     */
+    override fun createNodes(project: Project): NodeList<SourceGroup> =
+        KotlinSourceNodeList(project, includeJavaGroups = true, includeGradleOtherGroups = true, filterJavaKotlinRoots = false)
+}
+
+/** Replaces the J2SE Java node factory so broad Ant roots do not duplicate Kotlin folders. */
+class KotlinJ2SEProjectNodeFactory : NodeFactory {
+
+    /**
+     * Creates a source list with Java package trees filtered to omit conventional Kotlin roots.
+     *
+     * @param project J2SE/Ant project being rendered in Project Explorer
+     * @return dynamic list of separated Java and Kotlin source-root nodes
+     */
+    override fun createNodes(project: Project): NodeList<SourceGroup> =
+        KotlinSourceNodeList(project, includeJavaGroups = true, includeGradleOtherGroups = false, filterJavaKotlinRoots = true)
+}
+
+/**
+ * Produces PackageView nodes from standard and Kotlin source groups.
+ *
+ * The Gradle implementation uses public `Sources` type names deliberately: the Gradle Java
+ * implementation owns those types but the Kotlin plugin must not take a hard module dependency on it.
+ */
+private class KotlinSourceNodeList(
+    private val project: Project,
+    private val includeJavaGroups: Boolean,
+    private val includeGradleOtherGroups: Boolean,
+    private val filterJavaKotlinRoots: Boolean
+) : NodeList<SourceGroup>, ChangeListener {
+
+    private val changes = ChangeSupport(this)
+
+    /**
+     * Returns ordered source groups for Project Explorer.
+     *
+     * @return Java roots when requested, followed by separated Kotlin roots and Gradle auxiliary roots
+     */
+    override fun keys(): List<SourceGroup> {
+        val sources = ProjectUtils.getSources(project)
+        val groups = mutableListOf<SourceGroup>()
+        if (includeJavaGroups) {
+            val kotlinRoots = KotlinProjectSourceGroups.findRoots(project.projectDirectory).map(KotlinProjectSourceRoot::folder)
+            groups += sources.getSourceGroups(JavaProjectConstants.SOURCES_TYPE_JAVA)
+                .map { group -> if (filterJavaKotlinRoots) FilteredSourceGroup(group, kotlinRoots) else group }
+        }
+
+        val projectKotlinGroups = sources.getSourceGroups(KotlinProjectSourceGroups.KOTLIN_SOURCE_TYPE) +
+            sources.getSourceGroups(KotlinProjectSourceGroups.KOTLIN_TEST_SOURCE_TYPE)
+        val kotlinGroupPaths = projectKotlinGroups.map { it.rootFolder.path }.toSet()
+        val gradleKotlinGroups = sources.getSourceGroups("kotlin")
+            .filterNot { it.rootFolder.path in kotlinGroupPaths }
+        groups += gradleKotlinGroups.map(::labelKotlinGroup)
+        groups += projectKotlinGroups
+
+        if (includeGradleOtherGroups) {
+            groups += sources.getSourceGroups(JavaProjectConstants.SOURCES_TYPE_RESOURCES)
+            groups += sources.getSourceGroups("generated")
+        }
+        return groups.distinctBy { it.rootFolder.path }
+    }
+
+    /**
+     * Creates a package-view node for [key].
+     *
+     * @param key source group to render
+     * @return package tree rooted at [key]
+     */
+    override fun node(key: SourceGroup): Node = PackageView.createPackageView(key)
+
+    /** Starts listening for source-model changes. */
+    override fun addNotify() {
+        ProjectUtils.getSources(project).addChangeListener(this)
+    }
+
+    /** Stops listening for source-model changes. */
+    override fun removeNotify() {
+        ProjectUtils.getSources(project).removeChangeListener(this)
+    }
+
+    /**
+     * Schedules an Explorer refresh outside the source-model callback stack.
+     *
+     * @param event source-model change event
+     */
+    override fun stateChanged(event: ChangeEvent) {
+        REFRESH_PROCESSOR.post { changes.fireChange() }
+    }
+
+    /**
+     * Registers a [listener] for changes in source nodes.
+     *
+     * @param listener listener to register
+     */
+    override fun addChangeListener(listener: ChangeListener) {
+        changes.addChangeListener(listener)
+    }
+
+    /**
+     * Removes a [listener] from source-node changes.
+     *
+     * @param listener listener to remove
+     */
+    override fun removeChangeListener(listener: ChangeListener) {
+        changes.removeChangeListener(listener)
+    }
+
+    /** Gives a Gradle Kotlin source group a stable language-specific package-tree label. */
+    private fun labelKotlinGroup(group: SourceGroup): SourceGroup = when {
+        group.rootFolder.path.endsWith("/src/main/kotlin") ->
+            NamedSourceGroup(group, KotlinProjectSourceGroups.KOTLIN_SOURCE_PACKAGES)
+        group.rootFolder.path.endsWith("/src/test/kotlin") ->
+            NamedSourceGroup(group, KotlinProjectSourceGroups.KOTLIN_TEST_SOURCE_PACKAGES)
+        else -> group
+    }
+
+    private companion object {
+        val REFRESH_PROCESSOR = RequestProcessor(KotlinSourceNodeList::class.java)
+    }
+}