title: ToolProvider.getSystemJavaCompiler() returning null in JDK 9
body: <p>My project in Eclipse is running <strong>WITH SYSTEM JRE 9</strong>. When I try to set Java home to JDK 9 to get the system compiler I got null.</p>
  
  <pre><code>System.setProperty("java.home", "C:\\Program Files\\Java\\jdk-9.0.1");
  System.out.println(System.getProperty("java.home")); // print C:\Program Files\Java\jdk-9.0.1
  JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); // returns null
  </code></pre>
  
  <p>This code previously works fine with JDK 8 (running from JRE 8)</p>
  
  <pre><code>System.setProperty("java.home", "C:\\Program Files\\Java\\jdk1.8.0_152");
  System.out.println(System.getProperty("java.home")); // print C:\Program Files\Java\jdk1.8.0_152
  JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); // returns compiler
  </code></pre>
  
  <p>Has there been any change to how ToolProvider.getSystemJavaCompiler requirement works?</p>
  
  <p>Update: not sure if it matters but getSystemJavaCompiler() works fine if I run my project from JDK 9 (change to java.home is no longer required) as opposed to JRE 9.</p>