title: @SuppressWarnings("unchecked") not working with drag and drop
body: <p>I am using the following code that I found (<a href="https://stackoverflow.com/questions/811248/how-can-i-use-drag-and-drop-in-swing-to-get-file-path">How can I use Drag-and-Drop in Swing to get file path?</a> from ABika) to do drag and drop:</p>
  
  <pre><code>final class FileDropHandler extends TransferHandler {
      @Override
      public boolean canImport(TransferHandler.TransferSupport support) {
          for (DataFlavor flavor : support.getDataFlavors()) {
              if (flavor.isFlavorJavaFileListType()) {
                  return true;
              }
          }
          return false;
      }
  
      @Override
      @SuppressWarnings("unchecked")
      public boolean importData(TransferHandler.TransferSupport support) {
          if (!this.canImport(support))
              return false;
  
          List&lt;File&gt; files;
          try {
              files = (List&lt;File&gt;) support.getTransferable()
                      .getTransferData(DataFlavor.javaFileListFlavor);
          } catch (UnsupportedFlavorException | IOException ex) {
              // should never happen (or JDK is buggy)
              return false;
          }
  
          for (File file: files) {
              // do something...
          }
          return true;
      }
  }
  </code></pre>
  
  <p>The handler is then added to a component.</p>
  
  <p>But the problem is that despite the "@SuppressWarnings("unchecked")", I am getting an error:</p>
  
  <blockquote>
    <p>The type List is not generic; it cannot be parameterized with arguments &lt; File></p>
  </blockquote>
  
  <p>Can anyone tell me what is wrong here? It seems so straight-forward.
  Thanks</p>