I did a test with GWT 2.5.1 and the problem did not happen. Most likely your problem is in the class GetArticleResult.
Here is the code I used:
private String test1 = null;
private String test2 = null;
private AsyncCallback<GetArticleResult> callback = new AsyncCallback<GetArticleResult>() {
@Override
public void onFailure(Throwable throwable) {
Window.alert(throwable.getClass().getName() + " - " + throwable.getMessage());
}
@Override
public void onSuccess(GetArticleResult s) {
test1 = s.msg;
test2 = "123";
Window.alert(test1 + " - " + test2);
}
};
private class MyValueChangeHandler implements ValueChangeHandler<String> {
@Override
public void onValueChange(ValueChangeEvent<String> stringValueChangeEvent) {
Window.alert(test1 + " - " + test2);
}
}
And my GetArticleResult is very simple:
public class GetArticleResult implements IsSerializable {
public String msg;
}