xxhash hashing. This package supports both block hashing via net.jpountz.xxhash.XXHash32 and streaming hashing via net.jpountz.xxhash.StreamingXXHash32. Have a look at net.jpountz.xxhash.XXHashFactory to know how to get instances of these interfaces.

Streaming hashing is a little slower but doesn't require to load the whole stream into memory.

Sample block usage:

    XXHashFactory factory = XXHashFactory.fastestInstance();

    byte[] data = "12345345234572".getBytes("UTF-8");

    XXHash32 hash32 = factory.hash32();
    int seed = 0x9747b28c; // used to initialize the hash value, use whatever
                           // value you want, but always the same
    int hash = hash32.hash(data, 0, data.length, seed);

Sample streaming usage:

    XXHashFactory factory = XXHashFactory.fastestInstance();

    byte[] data = "12345345234572".getBytes("UTF-8");
    ByteArrayInputStream in = new ByteArrayInputStream(data);

    int seed = 0x9747b28c; // used to initialize the hash value, use whatever
                           // value you want, but always the same
    StreamingXXHash32 hash32 = factory.newStreamingHash32(seed);
    byte[] buf = new byte[8]; // for real-world usage, use a larger buffer, like 8192 bytes
    for (;;) {
      int read = in.read(buf);
      if (read == -1) {
        break;
      }
      hash32.update(buf, 0, read);
    }
    int hash = hash32.getValue();