NFC Empty Tag causes Error

Running sample "Annotated URL". When using an empty NFC tag:

W System.err: java.lang.IllegalStateException: Close other technology first!
W System.err: at android.nfc.Tag.setConnectedTechnology(Tag.java:458)
W System.err: at android.nfc.tech.BasicTagTechnology.connect(BasicTagTechnology.java:78)
W System.err: at android.nfc.tech.Ndef.connect(Ndef.java)

This prevents to implement functionality only based on UID instead of data sets.