[未解決] GradleのJavaプラグインタスクをbuild.gradle内でexecuteできない

解決してないので、どなたか原因や解決策を知っていたら教えてください。

とあるJavaプロジェクトで、defaultTasksを定義しているんだけど、Eclipseからだとタスク実行の方がやりやすいと。
で、タスクを作ってその中からタスクを呼ぼうとしているんだけど、タイトル通りJavaプラグイン関連のタスクが呼べない。

例えば、

```bash
% gradle init --type java-library
```

で作ったプロジェクトのbuild.gradleを最低限の記述にして、タスクを追加してみる。

```groovy
apply plugin: 'java'

repositories {
    jcenter()
}

dependencies {
    compile 'org.slf4j:slf4j-api:1.7.12'
    testCompile 'junit:junit:4.12'
}

task('noJava') << {
  println "no java task run"
}

task('run') << {
  project.tasks.getByName('noJava').execute()
}

task('runJava') << {
  project.tasks.getByName('build').execute()
}
```

この時、runタスクでnoJavaタスクは呼べるんだけど、runJavaタスクでbuildは呼べない。
--debugしてみると、buildタスクにはActionがないみたいなログが出ている。

なんか、Gradleの初歩的なことを見落としているような気がしているんだけど、割りと簡単なことができなくて困ってる…。

↓実行ログ

```
17:26:37.493 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Starting to execute task ':runJava'
17:26:37.493 [DEBUG] [org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter] Determining if task ':runJava' is up-to-date
17:26:37.493 [INFO] [org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter] Executing task ':runJava' (up-to-date check took 0.0 secs) due to:
  Task has not declared any outputs.
17:26:37.493 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter] Executing actions for task ':runJava'.
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Transitioning model element 'tasks.build' from state Discovered to Initialized
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Running model element 'tasks.build' rule action tasks.addPlaceholderAction(build)
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Mutating tasks.build using tasks.addPlaceholderAction(build)
17:26:37.509 [DEBUG] [org.gradle.model.collection.internal.BridgedCollections] Ignoring element 'tasks' added to 'build' after it is closed.
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Transitioning model element 'tasks.build' to state Created.
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Transitioning model element 'tasks.build' to state DefaultsApplied.
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Running model element 'tasks.build' rule action copyToTaskContainer
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Mutating tasks.build using copyToTaskContainer
17:26:37.509 [DEBUG] [org.gradle.model.internal.registry.DefaultModelRegistry] Transitioning model element 'tasks.build' to state Initialized.
17:26:37.509 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Starting to execute task ':build'
17:26:37.509 [INFO] [org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter] Skipping task ':build' as it has no actions.
17:26:37.509 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Finished executing task ':build'
17:26:37.509 [DEBUG] [org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter] Finished executing task ':runJava'
17:26:37.509 [INFO] [org.gradle.execution.taskgraph.AbstractTaskPlanExecutor] :runJava (Thread[main,5,main]) completed. Took 0.016 secs.
```