A Java Native Interface to LevelDB
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Latest commit ec644ea Oct 29, 2016 @davsclaus davsclaus committed on GitHub Merge pull request #81 from ibmsoe/new_master1
Add support for Linux PowerPC64LE (ppc64le)




LevelDB JNI gives you a Java interface to the LevelDB C++ library which is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values..

Getting the JAR

Just add the following jar to your java project: leveldbjni-all-1.8.jar

Using as a Maven Dependency

You just need to add the following dependency to your Maven pom.


By using the leveldbjni-all then the Java driver of leveldb is being used. If you want to use the native drivers, then use the os specific dependency instead of leveldbjni-all. For example to use linux 64 bit, then use this dependency:


API Usage:

Recommended Package imports:

import org.iq80.leveldb.*;
import static org.fusesource.leveldbjni.JniDBFactory.*;
import java.io.*;

Opening and closing the database.

Options options = new Options();
DB db = factory.open(new File("example"), options);
try {
  // Use the db in here....
} finally {
  // Make sure you close the db to shutdown the 
  // database and avoid resource leaks.

Putting, Getting, and Deleting key/values.

db.put(bytes("Tampa"), bytes("rocks"));
String value = asString(db.get(bytes("Tampa")));

Performing Batch/Bulk/Atomic Updates.

WriteBatch batch = db.createWriteBatch();
try {
  batch.put(bytes("Tampa"), bytes("green"));
  batch.put(bytes("London"), bytes("red"));

} finally {
  // Make sure you close the batch to avoid resource leaks.

Iterating key/values.

DBIterator iterator = db.iterator();
try {
  for(iterator.seekToFirst(); iterator.hasNext(); iterator.next()) {
    String key = asString(iterator.peekNext().getKey());
    String value = asString(iterator.peekNext().getValue());
    System.out.println(key+" = "+value);
} finally {
  // Make sure you close the iterator to avoid resource leaks.

Working against a Snapshot view of the Database.

ReadOptions ro = new ReadOptions();
try {

  // All read operations will now use the same 
  // consistent view of the data.
  ... = db.iterator(ro);
  ... = db.get(bytes("Tampa"), ro);

} finally {
  // Make sure you close the snapshot to avoid resource leaks.

Using a custom Comparator.

DBComparator comparator = new DBComparator(){
    public int compare(byte[] key1, byte[] key2) {
        return new String(key1).compareTo(new String(key2));
    public String name() {
        return "simple";
    public byte[] findShortestSeparator(byte[] start, byte[] limit) {
        return start;
    public byte[] findShortSuccessor(byte[] key) {
        return key;
Options options = new Options();
DB db = factory.open(new File("example"), options);

Disabling Compression

Options options = new Options();
DB db = factory.open(new File("example"), options);

Configuring the Cache

Options options = new Options();
options.cacheSize(100 * 1048576); // 100MB cache
DB db = factory.open(new File("example"), options);

Getting approximate sizes.

long[] sizes = db.getApproximateSizes(new Range(bytes("a"), bytes("k")), new Range(bytes("k"), bytes("z")));
System.out.println("Size: "+sizes[0]+", "+sizes[1]);

Getting database status.

String stats = db.getProperty("leveldb.stats");

Getting informational log messages.

Logger logger = new Logger() {
  public void log(String message) {
Options options = new Options();
DB db = factory.open(new File("example"), options);

Destroying a database.

Options options = new Options();
factory.destroy(new File("example"), options);

Repairing a database.

Options options = new Options();
factory.repair(new File("example"), options);

Using a memory pool to make native memory allocations more efficient:

JniDBFactory.pushMemoryPool(1024 * 512);
try {
    // .. work with the DB in here, 
} finally {



Supported Platforms

The following worked for me on:

  • OS X Lion with X Code 4
  • CentOS 5.6 (32 and 64 bit)
  • Ubuntu 12.04 (32 and 64 bit)
  • apt-get install autoconf libtool

Build Procedure

Then download the snappy, leveldb, and leveldbjni project source code:

wget http://snappy.googlecode.com/files/snappy-1.0.5.tar.gz
tar -zxvf snappy-1.0.5.tar.gz
git clone git://github.com/chirino/leveldb.git
git clone git://github.com/fusesource/leveldbjni.git
export SNAPPY_HOME=`cd snappy-1.0.5; pwd`
export LEVELDB_HOME=`cd leveldb; pwd`
export LEVELDBJNI_HOME=`cd leveldbjni; pwd`

Compile the snappy project. This produces a static library.

./configure --disable-shared --with-pic

Patch and Compile the leveldb project. This produces a static library.

git apply ../leveldbjni/leveldb.patch
make libleveldb.a

Now use maven to build the leveldbjni project.

mvn clean install -P download -P ${platform}

Replace ${platform} with one of the following platform identifiers (depending on the platform your building on):

  • osx
  • linux32
  • linux64
  • win32
  • win64
  • freebsd64

If your platform does not have the right auto-tools levels available just copy the leveldbjni-${version}-SNAPSHOT-native-src.zip artifact from a platform the does have the tools available then add the following argument to your maven build:


Build Results

  • leveldbjni/target/leveldbjni-${version}.jar : The java class file to the library.
  • leveldbjni/target/leveldbjni-${version}-native-src.zip : A GNU style source project which you can use to build the native library on other systems.
  • leveldbjni-${platform}/target/leveldbjni-${platform}-${version}.jar : A jar file containing the built native library using your currently platform.