EJB 2.0 & auto-increment

Question

How to implement EJB 2.0 Entity bean for auto increment DB filed, let's say I have table person(ID, name), ID is auto-increment PK, I have ejbCreate(ID, name), if I send null for ID that won't work (exception), if I have ejbCreate(name) that won't work because I receive exception from App. server regarding PK.
DB is mySQL, app. server is WebLogic 6.1

Answer 1

I think you just need to provide an id in ejbCreate. Usually this should never be manipulated by DBAs or application level code.
In ejbCreate(), call setId().
Of course, you'll need a way to generate guids.
The following may help in this respect...
private static final SecureRandom seeder = new SecureRandom();
public static final String generateGUID(Object obj) {
     StringBuffer buf = new StringBuffer(16);
     if (hexServerIP == null) {
          InetAddress localInetAddress = null;
          try {
               localInetAddress = InetAddress.getLocalHost();
          } catch (UnknownHostException e) {
               log.fatal("exception.guid.local.inet.address.unknown", e);
               return null;
          byte serverIP[] = localInetAddress.getAddress();
          hexServerIP = hexFormat(getInteger(serverIP), 8);
     String hashcode = hexFormat(System.identityHashCode(obj), 8);
     buf.append(hexServerIP);
     buf.append(hashcode);
     long timeNow = System.currentTimeMillis();
     int timeLow = (int)timeNow & 0xFFFFFFFF;
     int node = seeder.nextInt();
     StringBuffer guid = new StringBuffer(32);
     guid.append(hexFormat(timeLow, 8));
     guid.append(buf.toString());
     guid.append(hexFormat(node, 8));
     return guid.toString();
private static int getInteger(byte bytes[]) {
     int i = 0;
     int j = 24;
     for (int k = 0; j >= 0; k++) {
          int l = bytes[k] & 0xff;
          i += l << j;
          j -= 8;
     return i;
private static String hexFormat(int i, int j) {
     String s = Integer.toHexString(i);
     return padHex(s, j) + s;
private static String padHex(String s, int i) {
     StringBuffer buf = new StringBuffer();
     if (s.length() < i) {
          for (int j = 0; j < i - s.length(); j++) {
               buf.append('0');
     return buf.toString();
}hth
/k1