javascript File to java bytes[] with resteasy

I try to upload a file from an angularJS front to a jboss backoffice, but i get this exeption when service is called:

Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of byte[] out of START_OBJECT token
 at [Source: io.undertow.servlet.spec.ServletInputStreamImpl@1cc8ac9f; line: 1, column: 39] (through reference chain: fr.test.Document["datas"

])

I guess there is something wrong when i convert the javascript File in java bytes[], but i don't really know what.

I collect the file via a regular input type="file":

<input
type="file"
style="display: none;"
onchange="angular.element(this).controller().addDocument(this)"
>

Then i catch result with an onchange method in my controller: (i read on this link Return the Array of Bytes from FileReader() that i have to use a promise, that's return a bytes array).

...
ctrl.addDocument = function(element){
    var file = element.files[0];

    var fileData = new Blob([element.files[0]]);
    var promise = new Promise(
            function(resolve){
                var reader = new FileReader();
                reader.readAsArrayBuffer(fileData);
                reader.onload = function() {
                  var arrayBuffer = reader.result
                  var bytes = new Uint8Array(arrayBuffer);
                  resolve(bytes);
                }
            }
    );
    promise.then(function(data) {
        var document = {
                name: file.name,
                type: file.type,
                datas: data
            };
        console.dir(document);
        ctrl.doc = document;
    }).catch(function(err) {
        console.log(err);
         growl.error('Unable to upload file');
    });
}
...

Finally, backoffice is called, using a rest service. Here the declaration of my backoffice's service:

@POST
@Path("/uploadFile")
@Consumes(MediaType.APPLICATION_JSON)
public void uploadFile(Document document) {
    LOGGER.info("upload document !");
}

And the document object that contains same properties:

public class Document {

    private byte[] datas;
    private String name;
    private String type;

    public byte[] getDatas() {
        return datas;
    }
    public void setDatas(byte[] datas) {
        this.datas = datas;
    }
    ...

If i comment the line "ctrl.doc = document;" in my controller (the bytes part), service work correctly.

What i missed ? Can i really send a file this way ?