Resultset result;
PreparedStatement prep;
String query = "INSERT INTO myRel (data) VALUES (?)";

prep = db.prepareStatement(query ,Statement.RETURN_GENERATED_KEYS);

result = prep.getGeneratedKeys();

if(result.next() && result != null){
   System.out.println("Key: " + result.getInt(1));
} else {
   System.out.println("No, Nop nada");
}