我正在尝试使用Gradle构建JFXtras（the official JFXtras library），但我一直收到此错误：
* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':jfxtras-menu:compileJava'.
.......
Caused by: java.lang.RuntimeException: Cannot find System Java Compiler. Ensure that you have installed a JDK (not just a JRE) and configured your JAVA_HOME system variable to point to the according directory.
我正在使用：
java version "1.8.0_31"
Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
Java HotSpot(TM) Client VM (build 25.31-b07, mixed mode, sharing)
我可以成功编译一个简单的HelloWorld.java程序。
我可能做错了什么？
谢谢大家。
更新：
根据@Evans Belloeil的建议，我仍然没有成功。我收到类似于前一个错误的错误：
* What went wrong:
Execution failed for task ':jfxtras-menu:compileJava'.
> Cannot find System Java Compiler. Ensure that you have installed a JDK (not just a JRE) and configured your JAVA_HOME system variable to point to the according directory.
* Try:
Run with --info or --debug option to get more log output.