code: public void setOriginatingTransactionId(byte[] t) {
          if (t != null && t.length != 4)
              throw new IllegalArgumentException("TransactionId leng must be 4 bytes, found: " + t.length);
          this.originatingTransactionId = t;
  
      }
docs: /*
  (non-Javadoc)
  
  @seeorg.restcomm.protocols.ss7.tcap.asn.comp.TCBeginMessage# setOriginatingTransactionId(java.lang.String)