code: public static boolean equalsIgnoreCase(String str1, String str2) {
          return str1 == null ? str2 == null : str1.equalsIgnoreCase(str2);
      }
docs: <p>Compares two Strings, returning <code>true</code> if they are equal ignoring
  the case.</p>
  <p><code>null</code>s are handled without exceptions. Two <code>null</code>
  references are considered equal. Comparison is case insensitive.</p>
  
  <pre>
  StringUtils.equalsIgnoreCase(null, null)   = true
  StringUtils.equalsIgnoreCase(null, "abc")  = false
  StringUtils.equalsIgnoreCase("abc", null)  = false
  StringUtils.equalsIgnoreCase("abc", "abc") = true
  StringUtils.equalsIgnoreCase("abc", "ABC") = true
  </pre>
  
  @param str1 the first String, may be null
  @param str2 the second String, may be null
  @return <code>true</code> if the Strings are equal, case insensitive, or
  both <code>null</code>