public static int lastIndexOf(CharSequence seq, int searchChar) {
        if (isEmpty(seq)) {
            return INDEX_NOT_FOUND;
        }
        return CharSequenceUtils.lastIndexOf(seq, searchChar, seq.length());
    }
<p>Finds the last index within a CharSequence, handling {@code null}.
This method uses {@link String#lastIndexOf(int)} if possible.</p>

<p>A {@code null} or empty ("") CharSequence will return {@code -1}.</p>

<pre>
StringUtils.lastIndexOf(null, *)         = -1
StringUtils.lastIndexOf("", *)           = -1
StringUtils.lastIndexOf("aabaabaa", 'a') = 7
StringUtils.lastIndexOf("aabaabaa", 'b') = 5
</pre>

@param seq  the CharSequence 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)
android/android_framework/base/src/main/java/lang3/StringUtils.java