Intro to Java Programming. Please make sure to make java code simple and clean, also add comments, so that I can understand the process.

Write a recursive method that takes as a parameter a nonnegative integer and generates the following pattern of stars. If the nonnegative integer is 4, then the pattern generated is:

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*

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If the user enters a negative number or a nondigit , throw and handle an appropriate exception and prompt the user to enter a positive number.