Need help in writer in java code 7.13 and 7.14

Add a method public boolean isPermutationof(Sequence other) to the Sequence class of Exercise E7.11 that checks whether two sequences have the same values in some order, with the same multiplicities. For example, 1 4 9 16 9 7 4 9 11 is a permutation of 11 1 4 9 16 9 7 4 9 but 1 4 9 16 9 7 4 9 11 is not a permutation of 11 11 7 9 16 4 1 4 9 You will probably need one or more helper methods. Add a method public Sequence sum(Sequence other) to the sequence class of Exercise E7.11 that yields the sum of this sequence and another. If the sequences don't have the same length, assume that the missing elements are zero. For example, the sum of 1 4 9 16 9 7 4 9 11 and 11 11 7 9 16 4 1 is the sequence 12 15 16 25 25 11 5 9 11