In order to truely stay Java 8 compatible, declaring a source and
target compatiblity is not sufficient. Source compatiblity means that
the input, i.e. the code written in Java is compatible with that
particular version of the Java Language Specification (JLS). And
target compatibitliy means that the produced Java bytecode is
compatible with that particular version of the Java Virtual Machine
Specificiation (JVMS).
But there is actually a third dimension: the runtime
library (rt.jar). If signatures of methods change over java releases
within the runtime library, then the produced bytecode, may contain
calls to methods that do not exist with that exact same signature in
older java versions.
For example the family of Buffer subclasses changed the return value
of certain functions, for example flip() to not return Buffer, but the
concrete type of the current instance, e.g. CharBuffer.
If we compile now with a newer JDK, where the return type is
CharBuffer and not Buffer, then executing on an older JDK, where the
return type is Buffer, then we get java.lang.NoSuchMethodError(s)
thrown at us.
Fixes SMACK-651.
The previous site where the callback was invoked was only reached if
there was also a user status on the unvailable presence. But those are
not part of unavilable presences upon room destruction.
Fixes SMACK-888.
There is no need to duplicate that code. Also ensure that
userHasLeft() is invoked *before* the listeners are invoked, so that
e.g. isJoined() returns false in the listeners.
If it is announced as feature, entities sending fastened messages
expect the recipient to react somehow on those. And this is not the
case if this is just enabled in Smack.
Hence we disable it per default and require smack users to explicitly
enable it after they have setup the according stanza listeners.
The initState() method is also called in disconnect(). And if we reset
the closingStreamReceived sync point at disconnect, it will break the
WaitForClosingStreamElementTest integration test.
