Wittybrains Software Technologies Software Developer interview questions

1-Basic aptitude(40%) and reasoning(60%) 2-Technical face to face (i)They asked from basic core java and coding like alternate prime no from 1 to 100 (II)Suppose there is an array having an duplicate and non-duplicate element we have to print sum of all the duplicate element and product of all the duplicate element . (III) merge sort algorithm. after that i was waiting outside than hr say;s to me there will be another final round which is taking by TPO of company .

how to reverse the string?