code: public final void setApiMessageId(String value) {
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "setApiMessageId", value);
          if (value == null) {
              getApi().setField(JsApiAccess.MESSAGEID, null);
          }
          else if (value.startsWith(ID_STRING)) {
              byte[] binValue = HexString.hexToBin(value, 3);
              getApi().setField(JsApiAccess.MESSAGEID, binValue);
          }
          else {
              if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
                  SibTr.exit(this, tc, "setApiMessageId", "IllegalArgumentException");
              throw new IllegalArgumentException();
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "setApiMessageId");
      }
docs: /*
  Set the contents of the ApiMessageId field in the message header.
  
  Javadoc description supplied by JsApiMessage interface.