diff --git a/generators/src/org/jetbrains/kotlin/generators/arguments/GenerateGradleOptions.kt b/generators/src/org/jetbrains/kotlin/generators/arguments/GenerateGradleOptions.kt
index 7c42241e386..ed0712ceca5 100644
--- a/generators/src/org/jetbrains/kotlin/generators/arguments/GenerateGradleOptions.kt
+++ b/generators/src/org/jetbrains/kotlin/generators/arguments/GenerateGradleOptions.kt
@@ -34,14 +34,13 @@ interface AdditionalGradleProperties {
 }
 
 fun main(args: Array<String>) {
-    val dslSrcDir = File("libraries/tools/kotlin-gradle-plugin-dsl/src/main/kotlin")
-    val dslImplDir = File("libraries/tools/kotlin-gradle-plugin-core/src/main/kotlin")
+    val srcDir = File("libraries/tools/kotlin-gradle-plugin/src/main/kotlin")
     val additionalGradleOptions = gradleOptions<AdditionalGradleProperties>()
 
     // generate jvm interface
     val jvmInterfaceFqName = FqName("org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions")
     val optionsFromK2JVMCompilerArguments = gradleOptions<K2JVMCompilerArguments>()
-    File(dslSrcDir, jvmInterfaceFqName).usePrinter {
+    File(srcDir, jvmInterfaceFqName).usePrinter {
         generateInterface(jvmInterfaceFqName,
                           optionsFromK2JVMCompilerArguments + additionalGradleOptions)
     }
@@ -49,7 +48,7 @@ fun main(args: Array<String>) {
     // generate jvm impl
     val k2JvmCompilerArgumentsFqName = FqName(K2JVMCompilerArguments::class.qualifiedName!!)
     val jvmImplFqName = FqName("org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptionsBase")
-    File(dslImplDir, jvmImplFqName).usePrinter {
+    File(srcDir, jvmImplFqName).usePrinter {
         generateImpl(jvmImplFqName,
                      jvmInterfaceFqName,
                      k2JvmCompilerArgumentsFqName,
@@ -59,7 +58,7 @@ fun main(args: Array<String>) {
     // generate js interface
     val jsInterfaceFqName = FqName("org.jetbrains.kotlin.gradle.dsl.KotlinJsOptions")
     val optionsFromK2JSCompilerArguments = gradleOptions<K2JSCompilerArguments>()
-    File(dslSrcDir, jsInterfaceFqName).usePrinter {
+    File(srcDir, jsInterfaceFqName).usePrinter {
         generateInterface(jsInterfaceFqName,
                           optionsFromK2JSCompilerArguments +
                           additionalGradleOptions)
@@ -67,7 +66,7 @@ fun main(args: Array<String>) {
 
     val k2JsCompilerArgumentsFqName = FqName(K2JSCompilerArguments::class.qualifiedName!!)
     val jsImplFqName = FqName("org.jetbrains.kotlin.gradle.dsl.KotlinJsOptionsBase")
-    File(dslImplDir, jsImplFqName).usePrinter {
+    File(srcDir, jsImplFqName).usePrinter {
         generateImpl(jsImplFqName,
                      jsInterfaceFqName,
                      k2JsCompilerArgumentsFqName,
@@ -110,7 +109,7 @@ private fun Printer.generateImpl(
         argsType: FqName,
         properties: List<KProperty1<*, *>>
 ) {
-    generateDeclaration("abstract class", type, afterType = ": $parentType") {
+    generateDeclaration("internal abstract class", type, afterType = ": $parentType") {
         fun KProperty1<*, *>.backingField(): String = "${this.name}Field"
 
         for (property in properties) {
@@ -137,7 +136,7 @@ private fun Printer.generateImpl(
     }
 
     println()
-    println("fun $argsType.fillDefaultValues() {")
+    println("internal fun $argsType.fillDefaultValues() {")
     withIndent {
         for (property in properties) {
             println("${property.name} = ${property.gradleDefaultValue}")
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/AnnotationFileUpdater.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/AnnotationFileUpdater.kt
index 0f0dd2834c3..eabe285ffb4 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/AnnotationFileUpdater.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/AnnotationFileUpdater.kt
@@ -18,7 +18,7 @@ import java.util.*
  *  2.1 remove classes corresponding to dirty source files
  *  2.2 add annotations from newly generated annotations file
  */
-class AnnotationFileUpdater(private val generatedAnnotationFile: File) {
+internal class AnnotationFileUpdater(private val generatedAnnotationFile: File) {
     private val logger = Logging.getLogger(this.javaClass)
     private val lastSuccessfullyUpdatedFile = File.createTempFile("kapt-annotations-copy", "tmp")
 
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/SourceAnnotationsRegistry.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/SourceAnnotationsRegistry.kt
index 7b26c683d2d..cc0d84f4e2f 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/SourceAnnotationsRegistry.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/annotation/SourceAnnotationsRegistry.kt
@@ -4,7 +4,7 @@ import org.jetbrains.kotlin.incremental.components.SourceRetentionAnnotationHand
 import java.io.*
 import java.util.*
 
-class SourceAnnotationsRegistry(private val file: File) : SourceRetentionAnnotationHandler {
+internal class SourceAnnotationsRegistry(private val file: File) : SourceRetentionAnnotationHandler {
     private val mutableAnnotations: MutableSet<String> by lazy { readAnnotations() }
     val annotations: Set<String>
             get() = mutableAnnotations
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/bytecode/AnnotationsRemover.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/bytecode/AnnotationsRemover.kt
index 1eec613a507..b702e04c48e 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/bytecode/AnnotationsRemover.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/bytecode/AnnotationsRemover.kt
@@ -4,7 +4,7 @@ import org.jetbrains.org.objectweb.asm.*
 import java.io.File
 import java.util.*
 
-class AnnotationsRemover(annotations: Iterable<String>) {
+internal class AnnotationsRemover(annotations: Iterable<String>) {
     private val annotations = annotations.mapTo(HashSet()) { "L$it;" }
 
     fun transformClassFile(inputFile: File, outputFile: File) {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsBase.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsBase.kt
index 8c42f55ea0d..15ccbbb989a 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsBase.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsBase.kt
@@ -2,7 +2,7 @@
 // Generated by org/jetbrains/kotlin/generators/arguments/GenerateGradleOptions.kt
 package org.jetbrains.kotlin.gradle.dsl
 
-abstract class KotlinJsOptionsBase : org.jetbrains.kotlin.gradle.dsl.KotlinJsOptions {
+internal abstract class KotlinJsOptionsBase : org.jetbrains.kotlin.gradle.dsl.KotlinJsOptions {
 
     private var kjsmField: kotlin.Boolean? = null
     override var kjsm: kotlin.Boolean
@@ -74,7 +74,7 @@ abstract class KotlinJsOptionsBase : org.jetbrains.kotlin.gradle.dsl.KotlinJsOpt
     }
 }
 
-fun org.jetbrains.kotlin.cli.common.arguments.K2JSCompilerArguments.fillDefaultValues() {
+internal fun org.jetbrains.kotlin.cli.common.arguments.K2JSCompilerArguments.fillDefaultValues() {
     kjsm = true
     languageVersion = "1.0"
     main = "noCall"
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsImpl.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsImpl.kt
index de3ef5380f5..d0484908a21 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsImpl.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJsOptionsImpl.kt
@@ -3,7 +3,7 @@ package org.jetbrains.kotlin.gradle.dsl
 import org.jetbrains.kotlin.cli.common.arguments.K2JSCompilerArguments
 import org.jetbrains.kotlin.cli.js.K2JSCompiler
 
-class KotlinJsOptionsImpl() : KotlinJsOptionsBase() {
+internal class KotlinJsOptionsImpl() : KotlinJsOptionsBase() {
     override var freeCompilerArgs: List<String> = listOf()
 
     override fun updateArguments(args: K2JSCompilerArguments) {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsBase.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsBase.kt
index a23f9bfbe97..9928fb76877 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsBase.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsBase.kt
@@ -2,7 +2,7 @@
 // Generated by org/jetbrains/kotlin/generators/arguments/GenerateGradleOptions.kt
 package org.jetbrains.kotlin.gradle.dsl
 
-abstract class KotlinJvmOptionsBase : org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions {
+internal abstract class KotlinJvmOptionsBase : org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions {
 
     private var includeRuntimeField: kotlin.Boolean? = null
     override var includeRuntime: kotlin.Boolean
@@ -62,7 +62,7 @@ abstract class KotlinJvmOptionsBase : org.jetbrains.kotlin.gradle.dsl.KotlinJvmO
     }
 }
 
-fun org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments.fillDefaultValues() {
+internal fun org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments.fillDefaultValues() {
     includeRuntime = false
     jdkHome = null
     jvmTarget = "1.6"
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsImpl.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsImpl.kt
index d20627d5865..ac39002d427 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsImpl.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinJvmOptionsImpl.kt
@@ -3,7 +3,7 @@ package org.jetbrains.kotlin.gradle.dsl
 import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments
 import org.jetbrains.kotlin.cli.jvm.K2JVMCompiler
 
-open class KotlinJvmOptionsImpl : KotlinJvmOptionsBase() {
+internal class KotlinJvmOptionsImpl : KotlinJvmOptionsBase() {
     override var freeCompilerArgs: List<String> = listOf()
 
     override fun updateArguments(args: K2JVMCompilerArguments) {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/AnnotationProcessingManager.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/AnnotationProcessingManager.kt
index 458eafa0306..459fa7c315c 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/AnnotationProcessingManager.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/AnnotationProcessingManager.kt
@@ -40,7 +40,7 @@ import java.io.IOException
 import java.util.*
 import java.util.zip.ZipFile
 
-fun Project.initKapt(
+internal fun Project.initKapt(
         kotlinTask: KotlinCompile,
         javaTask: AbstractCompile,
         kaptManager: AnnotationProcessingManager,
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinGradleBuildServices.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinGradleBuildServices.kt
index a8db4a7cb6f..f11bbaca343 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinGradleBuildServices.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinGradleBuildServices.kt
@@ -40,7 +40,7 @@ private fun comparableVersionStr(version: String) =
                 ?.let { if (it.all { (it?.value?.length ?: 0).let { it > 0 && it < 4 }}) it else null }
                 ?.joinToString(".", transform = { it!!.value.padStart(3, '0') })
 
-class KotlinGradleBuildServices private constructor(gradle: Gradle): BuildAdapter() {
+internal class KotlinGradleBuildServices private constructor(gradle: Gradle): BuildAdapter() {
     companion object {
         private val CLASS_NAME = KotlinGradleBuildServices::class.java.simpleName
         const val FORCE_SYSTEM_GC_MESSAGE = "Forcing System.gc()"
@@ -133,7 +133,7 @@ class KotlinGradleBuildServices private constructor(gradle: Gradle): BuildAdapte
 }
 
 
-class CompilerServicesCleanup() {
+internal class CompilerServicesCleanup() {
     private val log = Logging.getLogger(this.javaClass)
 
     operator fun invoke(gradleVersion: String) {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPlugin.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPlugin.kt
index 7aef5af8f85..0606124817a 100755
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPlugin.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPlugin.kt
@@ -38,7 +38,7 @@ val KOTLIN_DSL_NAME = "kotlin"
 val KOTLIN_JS_DSL_NAME = "kotlin2js"
 val KOTLIN_OPTIONS_DSL_NAME = "kotlinOptions"
 
-abstract class KotlinSourceSetProcessor<T : AbstractKotlinCompile<*>>(
+internal abstract class KotlinSourceSetProcessor<T : AbstractKotlinCompile<*>>(
         val project: Project,
         val javaBasePlugin: JavaBasePlugin,
         val sourceSet: SourceSet,
@@ -91,7 +91,7 @@ abstract class KotlinSourceSetProcessor<T : AbstractKotlinCompile<*>>(
     protected abstract fun doCreateTask(project: Project, taskName: String): T
 }
 
-class Kotlin2JvmSourceSetProcessor(
+internal class Kotlin2JvmSourceSetProcessor(
         project: Project,
         javaBasePlugin: JavaBasePlugin,
         sourceSet: SourceSet,
@@ -166,7 +166,7 @@ class Kotlin2JvmSourceSetProcessor(
     }
 }
 
-class Kotlin2JsSourceSetProcessor(
+internal class Kotlin2JsSourceSetProcessor(
         project: Project,
         javaBasePlugin: JavaBasePlugin,
         sourceSet: SourceSet,
@@ -207,8 +207,12 @@ class Kotlin2JsSourceSetProcessor(
 }
 
 
-abstract class AbstractKotlinPlugin(val tasksProvider: KotlinTasksProvider, val kotlinSourceSetProvider: KotlinSourceSetProvider, val kotlinPluginVersion: String) : Plugin<Project> {
-    abstract fun buildSourceSetProcessor(project: Project, javaBasePlugin: JavaBasePlugin, sourceSet: SourceSet, kotlinPluginVersion: String): KotlinSourceSetProcessor<*>
+internal abstract class AbstractKotlinPlugin(
+        val tasksProvider: KotlinTasksProvider,
+        val kotlinSourceSetProvider: KotlinSourceSetProvider,
+        protected val kotlinPluginVersion: String
+) : Plugin<Project> {
+    internal abstract fun buildSourceSetProcessor(project: Project, javaBasePlugin: JavaBasePlugin, sourceSet: SourceSet, kotlinPluginVersion: String): KotlinSourceSetProcessor<*>
 
     override fun apply(project: Project) {
         val javaBasePlugin = project.plugins.apply(JavaBasePlugin::class.java)
@@ -230,8 +234,7 @@ abstract class AbstractKotlinPlugin(val tasksProvider: KotlinTasksProvider, val
     }
 }
 
-
-open class KotlinPlugin(
+internal open class KotlinPlugin(
         tasksProvider: KotlinTasksProvider,
         kotlinSourceSetProvider: KotlinSourceSetProvider,
         kotlinPluginVersion: String,
@@ -247,7 +250,7 @@ open class KotlinPlugin(
 }
 
 
-open class Kotlin2JsPlugin(
+internal open class Kotlin2JsPlugin(
         tasksProvider: KotlinTasksProvider,
         kotlinSourceSetProvider: KotlinSourceSetProvider,
         kotlinPluginVersion: String
@@ -256,7 +259,7 @@ open class Kotlin2JsPlugin(
             Kotlin2JsSourceSetProcessor(project, javaBasePlugin, sourceSet, tasksProvider, kotlinSourceSetProvider)
 }
 
-open class KotlinAndroidPlugin(
+internal open class KotlinAndroidPlugin(
         val tasksProvider: KotlinTasksProvider,
         private val kotlinSourceSetProvider: KotlinSourceSetProvider,
         private val kotlinPluginVersion: String,
@@ -509,7 +512,7 @@ private fun loadSubplugins(project: Project): SubpluginEnvironment {
     }
 }
 
-class SubpluginEnvironment(
+internal class SubpluginEnvironment(
         val subpluginClasspaths: Map<KotlinGradleSubplugin<KotlinCompile>, List<File>>,
         val subplugins: List<KotlinGradleSubplugin<KotlinCompile>>
 ) {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPluginWrapper.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPluginWrapper.kt
index 2ea4a437e76..02754e77047 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPluginWrapper.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinPluginWrapper.kt
@@ -25,7 +25,7 @@ abstract class KotlinBasePluginWrapper(protected val fileResolver: FileResolver)
         plugin.apply(project)
     }
 
-    protected abstract fun getPlugin(kotlinGradleBuildServices: KotlinGradleBuildServices): Plugin<Project>
+    internal abstract fun getPlugin(kotlinGradleBuildServices: KotlinGradleBuildServices): Plugin<Project>
 }
 
 open class KotlinPluginWrapper @Inject constructor(fileResolver: FileResolver): KotlinBasePluginWrapper(fileResolver) {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinSourceSetProvider.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinSourceSetProvider.kt
index f557fd59c3e..d96c6feeabf 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinSourceSetProvider.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KotlinSourceSetProvider.kt
@@ -1,5 +1,5 @@
 package org.jetbrains.kotlin.gradle.plugin
 
-interface KotlinSourceSetProvider {
+internal interface KotlinSourceSetProvider {
     fun create(displayName: String): KotlinSourceSet
 }
\ No newline at end of file
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/TaskToFriendTaskMapper.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/TaskToFriendTaskMapper.kt
index 576a3b5a96b..63132ebb37d 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/TaskToFriendTaskMapper.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/TaskToFriendTaskMapper.kt
@@ -19,7 +19,7 @@ package org.jetbrains.kotlin.gradle.plugin
 import org.gradle.api.Task
 import org.jetbrains.annotations.TestOnly
 
-abstract class TaskToFriendTaskMapper {
+internal abstract class TaskToFriendTaskMapper {
     operator fun get(task: Task): String? =
             getFriendByName(task.name)
 
@@ -30,7 +30,7 @@ abstract class TaskToFriendTaskMapper {
     protected abstract fun getFriendByName(name: String): String?
 }
 
-sealed class RegexTaskToFriendTaskMapper(
+sealed internal class RegexTaskToFriendTaskMapper(
         private val prefix: String,
         suffix: String
 ) : TaskToFriendTaskMapper() {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/gradleUtils.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/gradleUtils.kt
index cbb7aca7f52..6f98ffaba15 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/gradleUtils.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/gradleUtils.kt
@@ -30,7 +30,7 @@ internal fun Task.finalizedByIfNotFailed(finalizer: Task) {
     this.finalizedBy(finalizer)
 }
 
-fun AbstractCompile.mapClasspath(fn: ()->FileCollection) {
+internal fun AbstractCompile.mapClasspath(fn: ()->FileCollection) {
     conventionMapping.map("classpath", fn)
 }
 
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/ArtifactDifferenceRegistry.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/ArtifactDifferenceRegistry.kt
index e027cedfe9b..02d0a14d619 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/ArtifactDifferenceRegistry.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/ArtifactDifferenceRegistry.kt
@@ -3,10 +3,10 @@ package org.jetbrains.kotlin.gradle.tasks
 import org.jetbrains.kotlin.incremental.DirtyData
 import java.io.File
 
-interface ArtifactDifferenceRegistry {
+internal interface ArtifactDifferenceRegistry {
     operator fun get(artifact: File): Iterable<ArtifactDifference>?
     fun add(artifact: File, difference: ArtifactDifference)
     fun remove(artifact: File)
 }
 
-class ArtifactDifference(val buildTS: Long, val dirtyData: DirtyData)
\ No newline at end of file
+internal class ArtifactDifference(val buildTS: Long, val dirtyData: DirtyData)
\ No newline at end of file
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/CompilerPluginOptions.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/CompilerPluginOptions.kt
index cd6c4a61aae..45bbda43272 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/CompilerPluginOptions.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/CompilerPluginOptions.kt
@@ -2,7 +2,7 @@ package org.jetbrains.kotlin.gradle.tasks
 
 import java.io.File
 
-class CompilerPluginOptions {
+internal class CompilerPluginOptions {
     private val mutableClasspath = arrayListOf<String>()
     private val mutableArguments = arrayListOf<String>()
 
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/SyncOutputTask.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/SyncOutputTask.kt
index 9db60d581c7..aea2d425a16 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/SyncOutputTask.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/SyncOutputTask.kt
@@ -51,7 +51,7 @@ import kotlin.properties.Delegates
  * if it's timestamp now is newer than when we copied it
  * (assuming it was modified by javac when class was converted to java).
  */
-open class SyncOutputTask : DefaultTask() {
+internal open class SyncOutputTask : DefaultTask() {
     @get:InputFiles
     var kotlinOutputDir: File by Delegates.notNull()
     var javaOutputDir: File by Delegates.notNull()
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt
index 54709402642..e3cf42ada8b 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt
@@ -63,12 +63,12 @@ abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractCo
             System.setProperty("kotlin.incremental.compilation.experimental", value.toString())
         }
 
-    var compilerCalled: Boolean = false
+    internal var compilerCalled: Boolean = false
     // TODO: consider more reliable approach (see usage)
-    var anyClassesCompiled: Boolean = false
-    var friendTaskName: String? = null
-    var javaOutputDir: File? = null
-    var moduleName: String = "${project.name}-${this.name}"
+    internal var anyClassesCompiled: Boolean = false
+    internal var friendTaskName: String? = null
+    internal var javaOutputDir: File? = null
+    internal var moduleName: String = "${project.name}-${this.name}"
 
     override fun compile() {
         assert(false, { "unexpected call to compile()" })
@@ -109,7 +109,7 @@ abstract class AbstractKotlinCompile<T : CommonCompilerArguments>() : AbstractCo
 open class KotlinCompile : AbstractKotlinCompile<K2JVMCompilerArguments>(), KotlinJvmCompile {
     override val compiler = K2JVMCompiler()
 
-    var parentKotlinOptionsImpl: KotlinJvmOptionsImpl? = null
+    internal var parentKotlinOptionsImpl: KotlinJvmOptionsImpl? = null
     private val kotlinOptionsImpl = KotlinJvmOptionsImpl()
     override val kotlinOptions: KotlinJvmOptions
             get() = kotlinOptionsImpl
@@ -117,7 +117,7 @@ open class KotlinCompile : AbstractKotlinCompile<K2JVMCompilerArguments>(), Kotl
     private val sourceRoots = HashSet<File>()
 
     // lazy because name is probably not available when constructor is called
-    val taskBuildDirectory: File by lazy { File(File(project.buildDir, KOTLIN_BUILD_DIR_NAME), name).apply { mkdirs() } }
+    internal val taskBuildDirectory: File by lazy { File(File(project.buildDir, KOTLIN_BUILD_DIR_NAME), name).apply { mkdirs() } }
     private val cacheDirectory: File by lazy { File(taskBuildDirectory, CACHES_DIR_NAME) }
     private val dirtySourcesSinceLastTimeFile: File by lazy { File(taskBuildDirectory, DIRTY_SOURCES_FILE_NAME) }
     private val lastBuildInfoFile: File by lazy { File(taskBuildDirectory, LAST_BUILD_INFO_FILE_NAME) }
@@ -127,7 +127,7 @@ open class KotlinCompile : AbstractKotlinCompile<K2JVMCompilerArguments>(), Kotl
                dataContainerCacheVersion(taskBuildDirectory),
                gradleCacheVersion(taskBuildDirectory))
     }
-    val isCacheFormatUpToDate: Boolean
+    internal val isCacheFormatUpToDate: Boolean
         get() {
             if (!incremental) return true
 
@@ -143,12 +143,12 @@ open class KotlinCompile : AbstractKotlinCompile<K2JVMCompilerArguments>(), Kotl
             get() = File(project.buildDir, "generated/source/kapt2")
 
 
-    val kaptOptions = KaptOptions()
-    val pluginOptions = CompilerPluginOptions()
-    var artifactDifferenceRegistry: ArtifactDifferenceRegistry? = null
-    var artifactFile: File? = null
+    internal val kaptOptions = KaptOptions()
+    internal val pluginOptions = CompilerPluginOptions()
+    internal var artifactDifferenceRegistry: ArtifactDifferenceRegistry? = null
+    internal var artifactFile: File? = null
     // created only if kapt2 is active
-    var sourceAnnotationsRegistry: SourceAnnotationsRegistry? = null
+    internal var sourceAnnotationsRegistry: SourceAnnotationsRegistry? = null
 
     override fun populateCompilerArguments(): K2JVMCompilerArguments {
         val args = K2JVMCompilerArguments().apply { fillDefaultValues() }
@@ -578,7 +578,7 @@ open class KotlinCompile : AbstractKotlinCompile<K2JVMCompilerArguments>(), Kotl
         return super.source(*sourcesToAdd)
     }
 
-    fun findRootsForSources(sources: Iterable<File>): Set<File> {
+    internal fun findRootsForSources(sources: Iterable<File>): Set<File> {
         val resultRoots = HashSet<File>()
         val sourceDirs = sources.mapTo(HashSet()) { it.parentFile }
 
@@ -652,7 +652,7 @@ open class Kotlin2JsCompile() : AbstractKotlinCompile<K2JSCompilerArguments>(),
     }
 }
 
-class GradleMessageCollector(val logger: Logger, val outputCollector: OutputItemsCollector? = null) : MessageCollector {
+internal class GradleMessageCollector(val logger: Logger, val outputCollector: OutputItemsCollector? = null) : MessageCollector {
     private var hasErrors = false
 
     override fun hasErrors() = hasErrors
@@ -712,8 +712,7 @@ internal fun Logger.kotlinDebug(message: String) {
     this.debug("[KOTLIN] $message")
 }
 
-inline
-internal fun Logger.kotlinDebug(message: ()->String) {
+internal inline fun Logger.kotlinDebug(message: ()->String) {
     if (isDebugEnabled) {
         kotlinDebug(message())
     }
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/TasksProvider.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/TasksProvider.kt
index 72ef4201a62..efd5fce84a9 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/TasksProvider.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/TasksProvider.kt
@@ -5,7 +5,7 @@ import org.jetbrains.kotlin.gradle.plugin.RegexTaskToFriendTaskMapper
 import org.jetbrains.kotlin.gradle.plugin.TaskToFriendTaskMapper
 import org.jetbrains.kotlin.gradle.plugin.mapKotlinTaskProperties
 
-open class KotlinTasksProvider {
+internal open class KotlinTasksProvider {
     fun createKotlinJVMTask(project: Project, name: String): KotlinCompile {
         return project.tasks.create(name, KotlinCompile::class.java).apply {
             friendTaskName = taskToFriendTaskMapper[this]
@@ -21,7 +21,7 @@ open class KotlinTasksProvider {
             RegexTaskToFriendTaskMapper.Default()
 }
 
-class AndroidTasksProvider : KotlinTasksProvider() {
+internal class AndroidTasksProvider : KotlinTasksProvider() {
     override val taskToFriendTaskMapper: TaskToFriendTaskMapper =
             RegexTaskToFriendTaskMapper.Android()
 }
\ No newline at end of file
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/gradleCacheVersion.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/gradleCacheVersion.kt
index d30ca099f37..44aad26cec9 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/gradleCacheVersion.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/gradleCacheVersion.kt
@@ -4,10 +4,10 @@ import org.jetbrains.kotlin.config.IncrementalCompilation
 import org.jetbrains.kotlin.incremental.CacheVersion
 import java.io.File
 
-const val GRADLE_CACHE_VERSION = 1
-const val GRADLE_CACHE_VERSION_FILE_NAME = "gradle-format-version.txt"
+internal const val GRADLE_CACHE_VERSION = 1
+internal const val GRADLE_CACHE_VERSION_FILE_NAME = "gradle-format-version.txt"
 
-fun gradleCacheVersion(dataRoot: File): CacheVersion =
+internal fun gradleCacheVersion(dataRoot: File): CacheVersion =
         CacheVersion(ownVersion = GRADLE_CACHE_VERSION,
                 versionFile = File(dataRoot, GRADLE_CACHE_VERSION_FILE_NAME),
                 whenVersionChanged = CacheVersion.Action.REBUILD_ALL_KOTLIN,
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/incremental/multiProjectIncrementalCompilationUtil.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/incremental/multiProjectIncrementalCompilationUtil.kt
index 22c6e7cf980..fd0254453e8 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/incremental/multiProjectIncrementalCompilationUtil.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/incremental/multiProjectIncrementalCompilationUtil.kt
@@ -10,7 +10,7 @@ import org.jetbrains.kotlin.gradle.tasks.ArtifactDifferenceRegistry
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 import java.io.File
 
-fun configureMultiProjectIncrementalCompilation(
+internal fun configureMultiProjectIncrementalCompilation(
         project: Project,
         kotlinTask: KotlinCompile,
         javaTask: AbstractCompile,
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/kapt/kaptStubGeneratorUtils.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/kapt/kaptStubGeneratorUtils.kt
index f2a09680106..cf98d0f81a5 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/kapt/kaptStubGeneratorUtils.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/kapt/kaptStubGeneratorUtils.kt
@@ -4,7 +4,7 @@ import org.jetbrains.org.objectweb.asm.*
 import org.jetbrains.org.objectweb.asm.Opcodes.*
 import java.io.File
 
-fun generateKotlinAptAnnotation(outputDirectory: File): File {
+internal fun generateKotlinAptAnnotation(outputDirectory: File): File {
     val packageName = "__gen"
     val className = "KotlinAptAnnotation"
     val classFqName = "$packageName/$className"
@@ -25,7 +25,7 @@ fun generateKotlinAptAnnotation(outputDirectory: File): File {
     return outputFile
 }
 
-fun generateAnnotationProcessorWrapper(
+internal fun generateAnnotationProcessorWrapper(
         processorFqName: String,
         packageName: String,
         outputDirectory: File,
diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/incremental/snapshots/hashUtil.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/incremental/snapshots/hashUtil.kt
index d428e605c94..2e5448edf9c 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/incremental/snapshots/hashUtil.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/incremental/snapshots/hashUtil.kt
@@ -19,7 +19,7 @@ package org.jetbrains.kotlin.incremental.snapshots
 import java.io.File
 import java.security.MessageDigest
 
-val File.md5: ByteArray
+internal val File.md5: ByteArray
     get() {
         val messageDigest = MessageDigest.getInstance("MD5")
         val buffer = ByteArray(4048)
diff --git a/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/BaseGradleIT.kt b/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/BaseGradleIT.kt
index 176c6832535..eba342043d8 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/BaseGradleIT.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/BaseGradleIT.kt
@@ -2,7 +2,6 @@ package org.jetbrains.kotlin.gradle
 
 import org.gradle.api.logging.LogLevel
 import org.jetbrains.kotlin.com.intellij.openapi.util.io.FileUtil
-import org.jetbrains.kotlin.gradle.plugin.KotlinGradleBuildServices
 import org.jetbrains.kotlin.gradle.util.checkBytecodeNotContains
 import org.jetbrains.kotlin.gradle.util.createGradleCommand
 import org.jetbrains.kotlin.gradle.util.runProcess
@@ -183,8 +182,8 @@ abstract class BaseGradleIT {
     }
 
     fun CompiledProject.checkKotlinGradleBuildServices() {
-        assertSubstringCount(KotlinGradleBuildServices.INIT_MESSAGE, expectedCount = 1)
-        assertSubstringCount(KotlinGradleBuildServices.DISPOSE_MESSAGE, expectedCount = 1)
+        assertSubstringCount("Initialized KotlinGradleBuildServices", expectedCount = 1)
+        assertSubstringCount("Disposed KotlinGradleBuildServices", expectedCount = 1)
     }
 
     fun CompiledProject.assertNotContains(vararg expected: String): CompiledProject {
diff --git a/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinGradlePluginIT.kt b/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinGradlePluginIT.kt
index 764f861f4ce..710aa8c18a8 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinGradlePluginIT.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinGradlePluginIT.kt
@@ -1,7 +1,6 @@
 package org.jetbrains.kotlin.gradle
 
 import org.gradle.api.logging.LogLevel
-import org.jetbrains.kotlin.gradle.plugin.KotlinGradleBuildServices
 import org.jetbrains.kotlin.gradle.tasks.USING_EXPERIMENTAL_INCREMENTAL_MESSAGE
 import org.jetbrains.kotlin.gradle.util.getFileByName
 import org.jetbrains.kotlin.gradle.util.modify
@@ -106,12 +105,12 @@ class KotlinGradleIT: BaseGradleIT() {
     fun testLogLevelForceGC() {
         val debugProject = Project("simpleProject", GRADLE_VERSION, minLogLevel = LogLevel.DEBUG)
         debugProject.build("build") {
-            assertContains(KotlinGradleBuildServices.FORCE_SYSTEM_GC_MESSAGE)
+            assertContains("Forcing System.gc()")
         }
 
         val infoProject = Project("simpleProject", GRADLE_VERSION, minLogLevel = LogLevel.INFO)
         infoProject.build("clean", "build") {
-            assertNotContains(KotlinGradleBuildServices.FORCE_SYSTEM_GC_MESSAGE)
+            assertNotContains("Forcing System.gc()")
         }
     }