since we're not sharing folders with the vm, copy built .so files and jars back to host system.

java/RELEASE.md

@@ -1,12 +1,12 @@
 ## Cross-building
 
-To build RocksDB as a single self contained cross-platform JAR. The cross-platform jar can be usd on any 64-bit OSX system, 32-bit Linux system, or 64-bit Linux system.
+RocksDB can be built as a single self contained cross-platform JAR. The cross-platform jar can be usd on any 64-bit OSX system, 32-bit Linux system, or 64-bit Linux system.
 
 Building a cross-platform JAR requires:
 
  * [Vagrant](https://www.vagrantup.com/)
  * [Virtualbox](https://www.virtualbox.org/)
- * A Mac OSX machine
+ * A Mac OSX machine that can compile RocksDB.
 
 Once you have these items, run this make command from RocksDB's root source directory:
 

java/crossbuild/Vagrantfile

@@ -21,5 +21,6 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
     v.cpus = 4
   end
 
+  config.vm.synced_folder "../", "/rocksdb-build"
   config.vm.synced_folder "../..", "/rocksdb", type: "rsync"
 end

java/crossbuild/build-linux.sh

@@ -8,5 +8,7 @@ export JAVA_HOME=$(echo /usr/lib/jvm/java-7-openjdk*)
 cd /rocksdb
 make jclean clean
 make -j 4 rocksdbjavastatic
+cp /rocksdb/java/librocksdbjni-* /rocksdb-build
+cp /rocksdb/java/rocksdbjni-* /rocksdb-build
 sudo shutdown -h now