Using direct ByteBuffer is much nicer option to store or send
pointers between C(++) code and Java via JNI as it handles endiness
and pointer size for us. Using "long" type can have unexpected
results in 32-bit architectures (mostly Android). This was causing
grief especially when Android introduced support for 64-bit
architectures starting with SDK 19.

Change-Id: Ie92d0f913b668e1724e846d70d1820445d9cb086