how to read file from plugins to java class

how to read file from plugins to java class

Sir I used this plgins :
https://www.jqueryscript.net/form/Drag-Drop-File-Upload-Dialog-with-jQuery-Bootstrap.html

i have no idea to how to read file from plugins to ujava class
<!DOCTYPE html>
<html>
<head>
<script src=" https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link href="//netdna.bootstrapcdn.com/bootstrap/3.3.1/css/bootstrap.min.css" rel="stylesheet">
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
<script src="//netdna.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js"></script>

<link href="dist/bootstrap.fd.css" rel="stylesheet">
<script src="dist/bootstrap.fd.js"></script>
<script>
$(document).ready(function(){
$("#file_browse").click(function() {

     
     $.FileDialog({
  
          accept: "*",
          cancelButton: "Close",
          dragMessage: "Drop files here",
          dropheight: 150,
          errorMessage: "An error occured while loading file",
          multiple: true,
          okButton: "OK",
          readAs: "DataURL",
          removeMessage: "Remove&nbsp;file",
          title: "Load file(s)",
          url:" http://localhost:8080/sutisignweb/dashboard_display",

      });
    // uploadRequestDocFile();
    });

    });
</script>
<script type="text/javascript">
('#file_browse').on('files.bs.filedialog', function(ev) {
      var files_list = ev.files;
      // DO SOMETHING
    });
</script>

</head>
<body>

<button id="file_browse" title="Main Document" name="uploadFile" onchange="uploadRequestDocFile();">Open Dialog</button>

</body>
</html>