How to filter matched string row using filter function in java

Question

I am working java project. I am trying to filter a specific csv file if the the given string matches. Currently ,I am able to filter the rows from csv file but I want filter function to return the matched string rows rather than giving me rows which are not a match. how to achieve this ?

Here is the code i have so far:

File file = new File(original_file_format);

        //data to be searched
        final String    finString = "Humans";

        List<String> lines = FileUtils.readLines(file);
        List<String> updatedLines = lines.stream()
                .map(s-> s.trim())
        //currently i am getting output rows without "Humans" in it, but i want the rows which has "Humans" in it as output
                .filter(s ->  !s.matches(finString.trim())  ).collect(Collectors.toList());
        FileUtils.writeLines(file, updatedLines, false);