In UserOfMerge.java, the test will always give false.

This is because in the alphabet, "K" is before "Q". However, with cards, "Q" is before "K". Since Java follows the hierarchy of the alphabet, NOT cards, the test will always give false.

The lists are stored contiguously in a piece of an ArrayList, specified by the indexes at their boundaries.

For example, here is a picture of the two sorted lists of card values that we merged in class on Wednesday 2019-05-08, preceded by 2 positions whose values are to be ignored, and followed by 3 positions whose values are to be ignored. The values to be ignored are represented here by _.

values:  _ _ "4" "5" "6" "9" "2" "3" "4" "6" "7" "J" "Q" "K" _  _  _
indexes: 0 1  2   3   4   5   6   7   8   9   10  11  12  13 14 15 16 

The boundaries (check my counting!) are represented with half-open intervals:

• list0 starts at index 2 with the String value "4"
• list1 starts at index 6 with the String value "2". Since the lists are "stored contiguously", that 6 also marks the position just past the end of list0. The last value in list0 is therefore "9".
• list1 ends just before index 14, with a last value of "K".

The resulting, merged list is to occupy the original range. In the example above that means the interval [2,14).

We need not merge in place. (Doing so is apparently complicated.) So start your merge procedure by allocating storage to hold a copy of the data. Copy the data, then merge from the copy into the range whence it arrived.

You are of course welcome to look into in-place merges. But get this merge working first.