title: filename.delete() function and filename.renameTo(newfilename) function not returning positive results
body: <p>In my program, the <code>filename.delete()</code> and <code>filename.renameTo(newfilename)</code> functions always return <code>false</code>. My code:</p>
  
  <pre><code>    File file = new File("test.txt");
      File file1 = new File("test1.txt");
      boolean success1 = file.delete();
      boolean success2 = file1.renameTo(file);
      System.out.println(success1);
      System.out.println(success2);
  </code></pre>
  
  <p>Am I using them in the right way?</p>