can you please write the code of freqency

The same of final answer (4D,2c,2B)

3) void double () adds to the bag a copy of each entry that appears in the bag. For example, calling double () on the resulting bag in part 1 should change the bag contents to {4'D, 2B, 2C). be the big comes Create a test class called LinkedBagTest. In its main method, create and initialize the contents