Is this language Regular or non regular $(0^n 1)^* \ \ , n\geq 0 $
According to wiki

If V is a set of strings, then V* is defined as the smallest superset of V that contains the empty string ε and is closed under the string concatenation operation
If V is a set of symbols or characters, then V* is the set of all strings over symbols in V, including the empty string ε.

So this language accepts all strings over $\Sigma^*$ which must be regular.
Also regular languages are closed under kleene star.
But again on wiki

$V^* = \bigcup\limits_{i\geq 0}^{} V_i = {\epsilon} \ \cup \ V_1 \ \cup V_2 \ \cup \ V_3 \ \cup .....$

Now according to this definition strings such as $01001$ cannot be a part of given language so $0$'s prior of every 1 are compared within a string, so this can't be regular.
But according to the former definition $01001$ is a part of language because it can be formed with symbols $01$ and $001$ both are part of $0^n 1$.
Can someone help me in identifying the class of these types of languages

My reading of this question (which I think is the natural reading, notwithstanding other possibilities) is that the language being defined is:
$$L = \bigcup\limits_{n\geq 0}^{} (0^n1)^*$$
which is, roughly speaking, the language of all strings in $\{0,1\}^*$ ending in $1$ in which the $1$s are evenly-spaced. (In other words, there is an implicit "union over all $n$".) That language is not regular, which is easy to prove with the pumping lemma. (Take the string $(0^{p+1}1)^5$.)
I don't see any natural interpretation of $(0^n1)^*$ in which the $n$ is not fixed. It seems unlikely that the intent was $\left(\bigcup\limits_{n\geq 0}0^n1\right)^*$, since that would naturally be written $(0^*1)^*$, not $(0^n1)^*$. That language is regular, as you know, but I don't think it is relevant to this question. 
