title: java.io.File(parent, child) does not work as expected
body: <p>I am trying to construct a Java File object based on a user provided file name (could be absolute or relative) and a environment dependent base directory. The java doc for java.io.File(File parent, String child) says the following:</p>
  
  <blockquote>
    <p>If the child pathname string is absolute then it <strong>is converted into a relative pathname</strong> in a system-dependent way.</p>
  </blockquote>
  
  <p>That made me think that if I have the following code:</p>
  
  <pre><code>public class TestClass {
      public static void main(String[] args) throws IOException {
          File file = new File(new File("C:/Temp"),"C:/Temp/file.txt");
          System.out.println(file.getAbsolutePath());
      }
  }
  </code></pre>
  
  <p>the output would be</p>
  
  <pre><code>C:\Temp\file.txt
  </code></pre>
  
  <p>and then I'd be in business because it would not really matter anymore if the user provided an absolute or relative path. But in fact, the output is</p>
  
  <pre><code>C:\Temp\C:\Temp\file.txt
  </code></pre>
  
  <p>Which means I have to figure out the exact relative path (or at least test different options to see if the file exists). Am I misunderstanding the JavaDoc?</p>