Show a a method that checks if a given string is a palindrome or not by using an appropriate data structure from the Java collection framework.

Restrictions

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1. Stack and Queue classes are not allowed here.

2. you are allowed only to add(store) into the collection upto half size of the passed string (ex: if the passed string has 6 characters, then we are allowed to have only 3 characters to be stored in the collection).

3. To get the best performance do not traverse the string more than once.

4. No nested loops are allowed. However, sequential loops are OK if they are needed.