public static int lastIndexOfIgnoreCase(CharSequence str, CharSequence searchStr) {
        if (str == null || searchStr == null) {
            return INDEX_NOT_FOUND;
        }
        return lastIndexOfIgnoreCase(str, searchStr, str.length());
    }
<p>Case in-sensitive find of the last index within a CharSequence.</p>

<p>A {@code null} CharSequence will return {@code -1}.
A negative start position returns {@code -1}.
An empty ("") search CharSequence always matches unless the start position is negative.
A start position greater than the string length searches the whole string.</p>

<pre>
StringUtils.lastIndexOfIgnoreCase(null, *)          = -1
StringUtils.lastIndexOfIgnoreCase(*, null)          = -1
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A")  = 7
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B")  = 5
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB") = 4
</pre>

@param str  the CharSequence to check, may be null
@param searchStr  the CharSequence to find, may be null
@return the first index of the search CharSequence,
 -1 if no match or {@code null} string input
@since 2.5
@since 3.0 Changed signature from lastIndexOfIgnoreCase(String, String) to lastIndexOfIgnoreCase(CharSequence, CharSequence)
android/android_framework/base/src/main/java/lang3/StringUtils.java