Why is this string.replace line needed in generic.ObjectType constructor?

Why is this line present in the ObjectType constructor:
https://github.com/apache/commons-bcel/blob/5e2febea94ae56db7fd0729e808625f7be1f6a32/src/main/java/org/apache/bcel/generic/ObjectType.java#L45
 
The javadoc states that this constructor expects a fully qualified name(which do not contain '/'s). Is it some legacy stuff which is no longer needed since all the tests pass if I replace this line with this one:
this.class_name = class_name;