RegexBuddy is telling me if you want to include it at the beginning, this is the correct syntax:

"(?i)\\b(\\w+)\\b(\\s+\\1)+\\b"

From the way your question is worded, I'm not entirely sure whether you want the match to be case insensitive or not. This regex:

(?i)[^k][^b].*

uses the flag (?i) to turn off case sensitivity, and should do want you want.

all major regex help sites say (?i) is the correct java 7 syntax but Qradar regex engine spits errors.

so no one else is having issues with case-insensitive flag?

I don't understand why you can't use String.equalsIgnoreCase(). Regex is not needed for this. If you use a List, you can use .stream().anyMatch() with this Predicate:

c -> c.equalsIgnoreCase(data)

Code Sample:

public static void main(String[] args) throws Exception {
    List<String> check = new ArrayList() {{
        add("dog");  
        add("CAT");
        add("oWl");
        add("GiraFFe");
    }};

    Scanner scanner = new Scanner(System.in);
    System.out.print("Enter data: ");
    String data = scanner.nextLine();

    if (check.stream().anyMatch(c -> c.equalsIgnoreCase(data))) {
        System.out.println("Data found");
    } else {
        System.out.println("Data not found");
    }
}

Results:

Enter data: gIRAffE
Data found

Enter data: lamb
Data not found

To make it case insensitive, you can just modify your pattern as follows

   Pattern staPattern = Pattern.compile('[Ss][Tt][Aa][0-9]{4}');

This can be long winded if you have a long pattern, so then you use the ignore case modifier

 Pattern staPattern = Pattern.compile('(?i)sta[0-9]{4}');