code: public static int lastIndexOf(final CharSequence seq, final int searchChar) {
          if (isEmpty(seq)) {
              return INDEX_NOT_FOUND;
          }
          return CharSequenceUtils.lastIndexOf(seq, searchChar, seq.length());
      }
docs: Returns the index within <code>seq</code> of the last occurrence of
  the specified character. For values of <code>searchChar</code> in the
  range from 0 to 0xFFFF (inclusive), the index (in Unicode code
  units) returned is the largest value <i>k</i> such that:
  <blockquote><pre>
  this.charAt(<i>k</i>) == searchChar
  </pre></blockquote>
  is true. For other values of <code>searchChar</code>, it is the
  largest value <i>k</i> such that:
  <blockquote><pre>
  this.codePointAt(<i>k</i>) == searchChar
  </pre></blockquote>
  is true.  In either case, if no such character occurs in this
  string, then <code>-1</code> is returned. Furthermore, a {@code null} or empty ("")
  <code>CharSequence</code> will return {@code -1}. The
  <code>seq</code> <code>CharSequence</code> object is searched backwards
  starting at the last character.
  
  <pre>
  StringUtils.lastIndexOf(null, *)         = -1
  StringUtils.lastIndexOf("", *)           = -1
  StringUtils.lastIndexOf("aabaabaa", 'a') = 7
  StringUtils.lastIndexOf("aabaabaa", 'b') = 5
  </pre>
  
  @param seq  the <code>CharSequence</code> to check, may be null
  @param searchChar  the character to find
  @return the last index of the search character,
  -1 if no match or {@code null} string input
  @since 2.0
  @since 3.0 Changed signature from lastIndexOf(String, int) to lastIndexOf(CharSequence, int)
  @since 3.6 Updated {@link CharSequenceUtils} call to behave more like <code>String</code>