static boolean isAnagram(String a, String b) {
    java.util.Map<Character, Integer> m = new java.util.HashMap();
    for(int i = 0; i< a.length(); i++)
    {
        char x = Character.toLowerCase(a.charAt(i));
        if(m.containsKey(x)) {
            m.put(x, m.get(x) + 1);
        }
        else {
            m.put(x, 1);
        }
    }

    for(int i = 0; i< b.length(); i++)
    {
        char x = Character.toLowerCase(b.charAt(i));
        if(m.containsKey(x)) {
            int y = m.get(x);
            if(y > 0)
                m.put(x, y - 1);
            else return false;
        }
        else {
            return false;
        }
    }

    int sum = 0;

    for (java.util.Map.Entry<Character, Integer> entry : m.entrySet()) {
        sum += entry.getValue();
    }
// above loop can be replaced with:
//if ( a.length() != b.length() )
//    return false;


    return sum == 0 ? true : false ;
}