Can't Get GAE + GWT + Objectify to Work - google-app-engine

Question

As the title says, I'm trying to create a GAE + GWT project using Objectify but I can't even get it off the ground. I'm sure I'm missing something simple but doesn't seem to be working.
Here is what I've done so far:
Create a new project and added guava-17.0.jar, guava-gwt-17.0.jar, objectify-5.0.3.jar, and objectify-gwt-1.1jar to my WEB-INF\lib folder. These are all the latest versions of these jars.
Run the application. Send a simple RPC command, server responds, and client successfully receives response (onSuccess() is called).
Add the line <inherits name="com.googlecode.objectify.Objectify" /> to my gwt.xml file per Objectify-GWT's website which is supposed to enable Objectify in GWT.
Run the application. The application starts, same RPC command is sent, server receives and responds, but the client says the command was a failure (onFailure() is called).
I am using the boiler-plate code that is pre-populated when first create a new web application. For reference, here is the RPC command:
private void sendNameToServer() {
// First, we validate the input.
errorLabel.setText("");
String textToServer = nameField.getText();
if (!FieldVerifier.isValidName(textToServer)) {
errorLabel.setText("Please enter at least four characters");
return;
}
// Then, we send the input to the server.
sendButton.setEnabled(false);
textToServerLabel.setText(textToServer);
serverResponseLabel.setText("");
greetingService.greetServer(textToServer,
new AsyncCallback<String>() {
public void onFailure(Throwable caught) {
// Show the RPC error message to the user
dialogBox
.setText("Remote Procedure Call - Failure");
serverResponseLabel
.addStyleName("serverResponseLabelError");
serverResponseLabel.setHTML(SERVER_ERROR);
dialogBox.center();
closeButton.setFocus(true);
}
public void onSuccess(String result) {
dialogBox.setText("Remote Procedure Call");
serverResponseLabel
.removeStyleName("serverResponseLabelError");
serverResponseLabel.setHTML(result);
dialogBox.center();
closeButton.setFocus(true);
}
});
}
This is the error I receive after I try to make the RPC call:
[DEBUG] [my_app] - Validating units:
[INFO] [my_app] - Module my_app has been loaded
[ERROR] [my_app] - Errors in 'com/google/gwt/dev/jjs/SourceOrigin.java'
[ERROR] [my_app] - Line 77: The method synchronizedMap(new LinkedHashMap<SourceOrigin,SourceOrigin>(){}) is undefined for the type Collections
[ERROR] [my_app] - Errors in 'com/google/gwt/dev/util/StringInterner.java'
[ERROR] [my_app] - Line 29: No source code is available for type com.google.gwt.thirdparty.guava.common.collect.Interner<E>; did you forget to inherit a required module?
[ERROR] [my_app] - Line 29: No source code is available for type com.google.gwt.thirdparty.guava.common.collect.Interners; did you forget to inherit a required module?
To me it looks like Objectify is interfering with GWT. I know they're supposed to work together so not sure what I'm doing wrong. Any advice would be appreciated.

Answer 1

Use objectify-gwt 1.2. It's possible that 1.1 has some issues from merging a bad PR.
You can see a sample application that uses objectify-gwt to pass a GeoPt back and forth from the client here: https://github.com/stickfigure/objectify-gwt-test

Answer 2

You should use objectify on the server side before trying to do this kind of stuff. Objectify is a server side peristence technology. Call it in your server code
add try catch in your service methods and print the stack trace of the exception on your server console, if you receive onFailure() on GWT that means there is a failure on the server side. You have to find what is that failure.
Now the second part is an advice:
<inherits name="com.googlecode.objectify.Objectify" />
Is a weired line for me. GWT doesn't have to know about your persistence layer.
Unless it's a revolutionary concept, I would recommend you d'ont use this type of technology that removes your hand from the controle of your db access...