Use default compileJava9Java task to build java9 source set

libraries/stdlib/build.gradle

@@ -61,8 +61,6 @@ configurations {
     builtins
 }
 
-createCompileJava9Task(project, "compileJava9", "kotlin.stdlib", [sourceSets.builtins.output/* TODO: sourceSets.annotations.output?*/])
-
 task originalStdlibJar(type: Jar) {
     baseName = 'original-kotlin-stdlib'
     from sourceSets.main.output
@@ -73,7 +71,7 @@ jar {
     from("${rootDir}/dist/builtins")
     from sourceSets.builtins.output
     from sourceSets.experimental.output
-    from compileJava9.outputs
+    from sourceSets.java9.output
 }
 
 task distJar(type: Jar) {
@@ -85,7 +83,7 @@ task distJar(type: Jar) {
     from sourceSets.builtins.output
     from sourceSets.main.output
     from sourceSets.experimental.output
-    from compileJava9.outputs
+    from sourceSets.java9.output
 }
 
 task builtinsJar(type: Jar) {
@@ -168,4 +166,6 @@ compileExperimentalKotlin {
     }
 }
 
+compileJava9Sources(project, 'kotlin.stdlib', [sourceSets.builtins.output, sourceSets.main.output])
+
 kotlin.experimental.coroutines 'enable'

libraries/stdlib/jdk7/build.gradle

@@ -28,16 +28,14 @@ sourceSets {
     }
     java9 {
         java {
-            srcDirs = ['java9']
+            srcDir 'java9'
         }
     }
 }
 
-createCompileJava9Task(project, "compileJava9", "kotlin.stdlib.jdk7")
-
 jar {
     manifestAttributes(manifest, project, 'Main', true)
-    from compileJava9.outputs
+    from sourceSets.java9.output
 }
 
 artifacts {
@@ -68,6 +66,8 @@ compileTestKotlin {
     kotlinOptions.freeCompilerArgs = ["-Xallow-kotlin-package"]
 }
 
+compileJava9Sources(project, 'kotlin.stdlib.jdk7')
+
 kotlin.experimental.coroutines 'enable'
 
 test {

libraries/stdlib/jdk8/build.gradle

@@ -31,16 +31,14 @@ sourceSets {
     }
     java9 {
         java {
-            srcDirs = ['java9']
+            srcDir 'java9'
         }
     }
 }
 
-createCompileJava9Task(project, "compileJava9", "kotlin.stdlib.jdk8")
-
 jar {
     manifestAttributes(manifest, project, 'Main', true)
-    from compileJava9.outputs
+    from sourceSets.java9.output
 }
 
 artifacts {
@@ -71,6 +69,8 @@ compileTestKotlin {
     kotlinOptions.freeCompilerArgs = ["-Xallow-kotlin-package"]
 }
 
+compileJava9Sources(project, 'kotlin.stdlib.jdk8')
+
 kotlin.experimental.coroutines 'enable'
 
 test {