Task 1: DNA class

DNA consists of a sequence of nucleotides. Each nucleotide contains one of the four representative basis: guanine (G), adenine (A), thymine (T), or cytosine (C). The DNA strand can be simply represented as a sequence of the four letters, for example, AACTGCGAT.

You need to complete the implementation of the provided shell DNA class and make sure that it works with the attached simple program (see below for the code files).

DNA class description (for more details see the code):

• DNA(String sequence) constructor should create a DNA object. The sequence should be validated using the private validate() method
• validate() method is a private method used by the constructor to validate the DNA strand;
• toRNA() method converts the DNA object to RNA string; it should return null if the DNA sequence is invalid or of zero length;
• reverseComplement() computes and returns the complement DNA object for the DNA double helix; it should return null if the DNA sequence is invalid or of zero length

Once you finish with your implementation of the DNA class, test it using TestDNA class.

Source Code: DNA.java, TestDNA.java