fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph

Adam Retter c6d464a9da Fixed various memory leaks and Java 8 JNI Compatibility ... Summary: I have manually audited the entire RocksJava code base. Sorry for the large pull-request, I have broken it down into many small atomic commits though. My initial intention was to fix the warnings that appear when running RocksJava on Java 8 with `-Xcheck:jni`, for example when running `make jtest` you would see many errors similar to: ``` WARNING in native method: JNI call made without checking exceptions when required to from CallObjectMethod WARNING in native method: JNI call made without checking exceptions when required to from CallVoidMethod WARNING in native method: JNI call made without checking exceptions when required to from CallStaticVoidMethod ... ``` A few of those warnings still remain, however they seem to come directly from the JVM and are not directly related to RocksJava; I am in contact with the OpenJDK hostpot-dev mailing list about these - http://mail.openjdk.java.net/pipermail/hotspot-dev/2017-February/025981.html. As a result of fixing these, I realised we were not r Closes https://github.com/facebook/rocksdb/pull/1890 Differential Revision: D4591758 Pulled By: siying fbshipit-source-id: 7f7fdf4		8 years ago
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RocksDBColumnFamilySample.java	Fixed various memory leaks and Java 8 JNI Compatibility	8 years ago
RocksDBSample.java	Fixed various memory leaks and Java 8 JNI Compatibility	8 years ago