Try-catch bug

[incube8r]

For this code:

background.run(new Runnable() {
            @Override
            public void run() {
                try {
                    List<String> values= repository.get();
                    // stuff
                } catch (Exception e) {
                    Window.alert(e.getMessage()); 
                }
            }
        });

The exception is expected to be capture here and the alert should popup, but it does not if the repository code looks like this:

    public List<String> get() throws IOException {
        List<String> values= null;
        String body = null;
        body = ajaxCall();
        values = parse(body);
        return values;
    }

At this point the ajaxCall() did get a HTTP error but the exception did not propagate.
However, if we put the ajaxCall in a try-catch block the exception gets propagated above.

public List<String> get() {
    List<String> values= null;
    String body = null;
    try {
        body = ajaxCall();
        values = parse(body);
    } catch (IOException e) {
    }
    return values;
}

Shouldn't it be the reverse, since we already catch the exception in this code, then it should not propagate but what's happening is the reverse, is this a bug?