import org.bson.types.ObjectId;

public class ObjectIDTest {

  public static void main(String[] args) {
    String testString = "ffe764b2a43d0fd1416f86ed4a81b7407a508093";
    ObjectId oid = null;
    
    if (ObjectId.isValid(testString)) {
      oid = new ObjectId(testString);
    }
    
    if (oid != null) {
      System.out.println(oid.toString() + (oid.toString().equals(testString) ? " == " : " != " ) + testString );
    } else {
      System.err.println("oid was null");
    }
    
  }

}