RocksJava Basics

RocksJava is a project to build high performance but easy-to-use Java driver for RocksDB. In this page you will learn the basics of RocksDB Java API.

Getting Started

To build RocksJava, the first thing is to specify the environmental variable JAVA_HOME to where you install Java SDK. Once JAVA_HOME is properly set, simply run make rocksdbjava will build the Java binding for RocksDB:

rocksdb $ make rocksdbjava

This will generate rocksdbjni.jar and librocksdbjni.so (or librocksdbjni.jnilib in Mac) in java/ directory under the rocksdb's root directory. Specifically, rocksdbjni.jar contains the Java classes that defines the Java API for RocksDB, while librocksdbjni.so includes the C++ rocksdb library and the native implementation of the Java classes defined in rocksdbjni.jar.

Once make rocksdbjava is completed, make jtest will build and run the RocksJava sample code and tests. The output should look something like the followings:

rocksdb $ make jtest
javac org/rocksdb/util/*.java org/rocksdb/*.java
jar -cf rocksdbjni.jar org/rocksdb/*.class org/rocksdb/util/*.class
javah -d ./include -jni org.rocksdb.RocksDB org.rocksdb.Options org.rocksdb.WriteBatch org.rocksdb.WriteBatchInternal org.rocksdb.WriteBatchTest org.rocksdb.WriteOptions org.rocksdb.BackupableDB org.rocksdb.BackupableDBOptions org.rocksdb.Statistics org.rocksdb.Iterator org.rocksdb.VectorMemTableConfig org.rocksdb.SkipListMemTableConfig org.rocksdb.HashLinkedListMemTableConfig org.rocksdb.HashSkipListMemTableConfig org.rocksdb.PlainTableConfig org.rocksdb.ReadOptions org.rocksdb.Filter org.rocksdb.BloomFilter
javac -cp rocksdbjni.jar RocksDBSample.java
java -ea -Djava.library.path=.:../ -cp ".:./*" -Xcheck:jni RocksDBSample /tmp/rocksdbjni
RocksDBSample
caught the expceted exception -- org.rocksdb.RocksDBException: Invalid argument: /tmp/rocksdbjni_not_found: does not exist (create_if_missing is false)
Get('hello') = world
1 2 3 4 5 6 7 8 9
2 4 6 8 10 12 14 16 18
3 6 9 12 15 18 21 24 27
4 8 12 16 20 24 28 32 36
5 10 15 20 25 30 35 40 45
6 12 18 24 30 36 42 48 54
7 14 21 28 35 42 49 56 63
8 16 24 32 40 48 56 64 72
9 18 27 36 45 54 63 72 81
getTickerCount() passed.
geHistogramData() passed.
iterator seekToFirst tests passed.
iterator seekToLastPassed tests passed.
iterator seek test passed.
iterator tests passed.
javac org/rocksdb/util/*.java org/rocksdb/*.java
jar -cf rocksdbjni.jar org/rocksdb/*.class org/rocksdb/util/*.class
javah -d ./include -jni org.rocksdb.RocksDB org.rocksdb.Options org.rocksdb.WriteBatch org.rocksdb.WriteBatchInternal org.rocksdb.WriteBatchTest org.rocksdb.WriteOptions org.rocksdb.BackupableDB org.rocksdb.BackupableDBOptions org.rocksdb.Statistics org.rocksdb.Iterator org.rocksdb.VectorMemTableConfig org.rocksdb.SkipListMemTableConfig org.rocksdb.HashLinkedListMemTableConfig org.rocksdb.HashSkipListMemTableConfig org.rocksdb.PlainTableConfig org.rocksdb.ReadOptions org.rocksdb.Filter org.rocksdb.BloomFilter
javac org/rocksdb/test/*.java
java -ea -Djava.library.path=.:../ -cp "rocksdbjni.jar:.:./*" org.rocksdb.WriteBatchTest
Testing WriteBatchTest.Empty ===
Testing WriteBatchTest.Multiple ===
Testing WriteBatchTest.Append ===
Testing WriteBatchTest.Blob ===
Passed all WriteBatchTest!
java -ea -Djava.library.path=.:../ -cp "rocksdbjni.jar:.:./*" org.rocksdb.test.BackupableDBTest
java -ea -Djava.library.path=.:../ -cp "rocksdbjni.jar:.:./*" org.rocksdb.test.OptionsTest
Passed OptionsTest
java -ea -Djava.library.path=.:../ -cp "rocksdbjni.jar:.:./*" org.rocksdb.test.ReadOptionsTest
Passed ReadOptionsTest