Add Java tasks to relevant compilation APIs

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/jvm/KotlinJvmAndroidCompilation.kt

@@ -9,8 +9,11 @@ package org.jetbrains.kotlin.gradle.plugin.mpp
 import com.android.build.gradle.api.BaseVariant
 import org.gradle.api.file.FileCollection
 import org.gradle.api.provider.Property
+import org.gradle.api.tasks.TaskProvider
+import org.gradle.api.tasks.compile.JavaCompile
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
+import org.jetbrains.kotlin.gradle.plugin.getJavaTaskProvider
 import org.jetbrains.kotlin.gradle.plugin.getTestedVariantData
 
  class KotlinJvmAndroidCompilation(
@@ -46,4 +49,7 @@ import org.jetbrains.kotlin.gradle.plugin.getTestedVariantData
              androidVariant.compileConfiguration.name,
              androidVariant.runtimeConfiguration.name
          )
+
+     val compileJavaTaskProvider: TaskProvider<out JavaCompile>?
+         get() = androidVariant.getJavaTaskProvider()
  }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/jvm/KotlinJvmCompilation.kt

@@ -6,9 +6,12 @@
 @file:Suppress("PackageDirectoryMismatch") // Old package for compatibility
 package org.jetbrains.kotlin.gradle.plugin.mpp
 
+import org.gradle.api.plugins.JavaPluginConvention
+import org.gradle.api.tasks.compile.JavaCompile
 import org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions
+import org.gradle.api.tasks.TaskProvider
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationWithResources
-import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
+import org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget
 
 open class KotlinJvmCompilation(
     override val target: KotlinJvmTarget,
@@ -23,4 +26,12 @@ open class KotlinJvmCompilation(
 
     override val compileKotlinTask: org.jetbrains.kotlin.gradle.tasks.KotlinCompile
         get() = super.compileKotlinTask as org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
+    val compileJavaTaskProvider: TaskProvider<out JavaCompile>?
+        get() = if (target.withJavaEnabled) {
+            val project = target.project
+            val javaSourceSets = project.convention.getPlugin(JavaPluginConvention::class.java).sourceSets
+            val javaSourceSet = javaSourceSets.getByName(compilationName)
+            project.tasks.withType(JavaCompile::class.java).named(javaSourceSet.compileJavaTaskName)
+        } else null
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/jvm/KotlinWithJavaCompilation.kt

@@ -8,6 +8,8 @@ package org.jetbrains.kotlin.gradle.plugin.mpp
 
 import org.gradle.api.file.FileCollection
 import org.gradle.api.tasks.SourceSet
+import org.gradle.api.tasks.TaskProvider
+import org.gradle.api.tasks.compile.JavaCompile
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationOutput
@@ -71,4 +73,7 @@ import org.jetbrains.kotlin.gradle.tasks.AbstractKotlinCompile
             }
         }
     }
+
+    val compileJavaTaskProvider: TaskProvider<out JavaCompile>
+        get() = target.project.tasks.withType(JavaCompile::class.java).named(javaSourceSet.compileJavaTaskName)
 }