Github user kedar-joshi commented on the issue:
https://github.com/apache/commons-lang/pull/294
Also, length of the `source` can be cached for better performance e.g.
```java
for (int i = 0, length = source.length(); i < length; i++)
{
if (searchKey.equals(source.charAt(i)))
{
indexList.add(i);
}
}
```---
