jetbrick-commons/src/main/java/jetbrick/lang/StringUtils.java
public static String substringBetween(final String s, final String tag) {
        return substringBetween(s, tag, tag);
    }
public static String substringBetween(final String s, final String tag) {
        return substringBetween(s, tag, tag);
    }
<p>
Gets the String that is nested in between two instances of the same
String.
</p>

<p>
A {@code null} input String returns {@code null}. A {@code null} tag
returns {@code null}.
</p>

<pre>
StringUtils.substringBetween(null, *)            = null
StringUtils.substringBetween("", "")             = ""
StringUtils.substringBetween("", "tag")          = null
StringUtils.substringBetween("tagabctag", null)  = null
StringUtils.substringBetween("tagabctag", "")    = ""
StringUtils.substringBetween("tagabctag", "tag") = "abc"
</pre>