GWT Uploader
GWT library that encapsulates the browser's file upload capabilities.
...Using GWT Uploader allows for enhanced file upload dialogs (multiple uploads, drag and drop, queues, parallel streams, etc.) and interactive interfaces (upload progress indicators, real-time throughput display, etc.) within GWT applications using pure Java code that provides a consistent experience across all browsers.
If the browser is capable of handling file uploads using a modern HTML5 approach, the upload is handled using pure DOM elements and Javascript events. In the case that the browser does not support the modern approach (most notably IE 9 and earlier), the GWT Uploader component instead transparently handles the uploads via the Flash-based SWFUpload library.