<body>
<form action="<%= blobstoreService.createUploadUrl("/upload") %>"
method="post"
enctype="multipart/form-data"
>
<input type="file" name="myFile">
<input type="submit" value="Submit">
</form>
</body>
the above code throws a java.lang.NoSuchMethodError on compilation.I can't understand and what is blobstoreService in the above code ?