code: public static boolean equalsIgnoreCase(String str1, String str2) {
          return (str1 == null || str2 == null)
                  ? false
                  : (str1 == str2 || lowerCaseInternal(str1).equals(lowerCaseInternal(str2)));
      }
docs: Returns true if two strings are equals ignoring the letter case in {@link #LOCALE_INTERNAL} locale.
  
  @param str1 first string to compare
  @param str2 second string to compare
  @return true if the strings are equals ignoring the case