title: Java Compiler run() method
body: <p>I found this code online about the JavaCompiler</p>
  
  <pre><code>JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
  int result = compiler.run(null, null, null,
               "src/org/kodejava/example/tools/Hello.java");
  </code></pre>
  
  <p>And it says for the <code>compiler.run(null, null, null</code> that these three nulls are the default <code>System.in</code>, <code>System.out</code> and <code>System.err</code> respectively. But what do these values actually do as I cannot find the API for these? Could someone please explain?</p>