UniqueId (UUID) embedded primary key in JPA 2 (Hibernate) for MySQL

UniqueId.java

import java.io.Serializable;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.UUID;

import javax.persistence.Access;
import javax.persistence.AccessType;
import javax.persistence.Column;
import javax.persistence.Embeddable;

@Embeddable
@Access(AccessType.FIELD)
public class UniqueId implements Serializable {
  private static final long serialVersionUID = 4458438725376203754L;
  @Column(columnDefinition="BINARY(16)", length=16, updatable=false, nullable=false)
  private byte[] id;
  
  public UniqueId() {}
  
  public UniqueId(byte[] id) {
    this.id = id;
  }
  
  public UniqueId(String id) {
  	this(toByteArray(UUID.fromString(id)));
  }
  
  @Override
  public String toString() {
    return toUUID(id).toString();
  }
  
  public static UniqueId fromString(String s) {
    return fromUUID(UUID.fromString(s));
  }  
  
  public static UniqueId fromUUID(UUID uuid) {
    return new UniqueId(toByteArray(uuid));
  }
  
  private static byte[] toByteArray(UUID uuid) {
    ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
    bb.putLong(uuid.getMostSignificantBits()); // order is important here!
    bb.putLong(uuid.getLeastSignificantBits());
    return bb.array();
  }
  
  private static UUID toUUID(byte[] byteArray) {
    long msb = 0;
    long lsb = 0;
    for (int i = 0; i < 8; i++)
            msb = (msb << 8) | (byteArray[i] & 0xff);
    for (int i = 8; i < 16; i++)
            lsb = (lsb << 8) | (byteArray[i] & 0xff);
    UUID result = new UUID(msb, lsb);
    return result;
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + Arrays.hashCode(id);
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    UniqueId other = (UniqueId) obj;
    if (!Arrays.equals(id, other.id))
      return false;
    return true;
  }

  public static UniqueId generate() {
    return fromUUID(UUID.randomUUID());
  }
}

Lifesaver! Used this for general byte[] primary keys with a reordered UUID component