In java-nio.cpp, we can't use GetPrimitiveArrayCritical when reading
from or writing to blocking sockets since it may block the rest of the
VM indefinitely.
In SelectableChannel.java, we can't use a null test on
SelectableChannel.key to determine whether the channel is open since
it might never be registered with a Selector. According to the Sun
documentation, a SelectableChannel is open as soon as it's created, so
that's what we now implement.
and server socket channels are implemented. This version works but only when
libnative is linked with g++ (because of C++ object creation code that fails
without this linking)