You need to use

Collections.sort(a, String.CASE_INSENSITIVE_ORDER);

in order to sort ignoring case, you can use the equalsIgnoreCase method on String to compare to values

You can of course create your own CaseInsensitiveList class, we have a CaseInsensitiveSet & CaseInsensitiveMap in our codebase

I'm guessing you mean ignoring case when searching in a string?

I don't know any, but you could try to convert the string to search into either to lower or to upper case, then search.

// s is the String to search into, and seq the sequence you are searching for.
bool doesContain = s.toLowerCase().contains(seq);

Edit: As Ryan Schipper suggested, you can also (and probably would be better off) do seq.toLowerCase(), depending on your situation.

In Java8, using anyMatch

List<String> list = Arrays.asList("XYZ", "ABC");
String matchingText = "xYz";

boolean isMatched = list.stream().anyMatch(matchingText::equalsIgnoreCase);

If you are using Java7, simply override the contains() method,

public class CastInsensitiveList extends ArrayList<String> {
    @Override
    public boolean contains(Object obj) {
        String object = (String)obj;
        for (String string : this) {
            if (object.equalsIgnoreCase(string)) {
              return true;
            }
        }
        return false;
    }
}

If you are using Java 8.0, using streaming API,

List<String> arrayList = new ArrayList<>();
arrayList.stream().anyMatch(string::equalsIgnoreCase);

It is very unclear what you are trying to do, but you can sort a list like this:

List<String> fruits = new ArrayList<String>(7);

fruits.add("Pineapple");
fruits.add("apple");
fruits.add("apricot");
fruits.add("Banana");
fruits.add("mango");
fruits.add("melon");        
fruits.add("peach");

System.out.println("Unsorted: " + fruits);

Collections.sort(fruits, new Comparator<String>() {
    @Override
    public int compare(String o1, String o2) {              
        return o1.compareToIgnoreCase(o2);
    }
});

System.out.println("Sorted: " + fruits);

just include, speciality =spec.toLowerCase(); and convert the first character to uppercase

public void setSpeciality(String spec) {
    if(specialities.stream().anyMatch(s-> s.equalsIgnoreCase(spec))) {
        speciality =spec.toLowerCase();
        speciality = String.valueOf((speciality.charAt(0)).toUpperCase())  + speciality.substring(1) ;
    }
    else {
          speciality = "General Practitioner";
    }
}