StAX's NamespaceContext.getNamespaceURI(String) is allowed to throw an
IllegalArgumentException in case the argument is null. We simply
re-use getNamespace(String) which will substitute the default
namespace if the argument is null to avoid this.
Connection closed due to an exception
java.lang.IllegalArgumentException: Illegal to pass null as argument
at com.ctc.wstx.sr.NsInputElementStack.getNamespaceURI(NsInputElementStack.java:486)
at org.jivesoftware.smack.xml.stax.StaxXmlPullParser.getNamespace(StaxXmlPullParser.java:113)
at org.jivesoftware.smack.AbstractXMPPConnection.parseFeatures(AbstractXMPPConnection.java:1852)
at org.jivesoftware.smack.AbstractXMPPConnection.parseFeaturesAndNotify(AbstractXMPPConnection.java:1887)
at org.jivesoftware.smack.tcp.XMPPTCPConnection.access$1300(XMPPTCPConnection.java:130)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.parsePackets(XMPPTCPConnection.java:983)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.access$700(XMPPTCPConnection.java:913)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader$1.run(XMPPTCPConnection.java:936)
at java.lang.Thread.run(Thread.java:748)
Fixes SMACK-903
Introducing Smack's own XmlPullParser interface which tries to stay as
compatible as possible to XPP3. The interface is used to either wrap
StAX's XMLStreamReader if Smack is used on Java SE, and XPP3's
XmlPullParser if Smack is used on on Android.
Fixes SMACK-591.
Also introduce JUnit 5 and non-strict javadoc projects.