public int countCharOccurs(String str, int dt, String pattern) {
        try {
            Thread.sleep(dt);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
            Thread.currentThread().interrupt();
        }

        int count = 0;
        int lastIndex = 0;

        while(lastIndex != -1) {

            lastIndex = str.indexOf(pattern, lastIndex);

            if(lastIndex != -1){
                count += 1;
                lastIndex += 1;
            }
        }

        return count;
    }


// test

            Vector<Object> paramss = new Vector<Object>();
            paramss.addElement("aaaa");
            paramss.addElement(3000);
            paramss.addElement("a");
            int count = (int)srv.execute("MojSerwer.countCharOccurs", paramss);
            System.out.println("ile powtorzen:" + count);