\((.*?)\)

String x= "app1(UP) and app2(DOWN)";
    Matcher m = Pattern.compile("\((.*?)\)").matcher(x);
    String tmp="";
    StringBuilder sb = new StringBuilder();
    while(m.find()) {
        sb.append((m.group(1))+",");
    }

    System.out.println(sb.toString());

    //output :: UP,DOWN,