Write it, run it, read the output

This is a scratch drill — your code runs, nothing is graded or recorded. No test cases, no expected output, no verdict.

TASK

Use Java ArrayList<Integer> to reproduce [4, 2, 7] -> [4, 6, 7] -> [4, 6, 7, 1] -> [4, 6, 7]. Print the final size on one line and the final elements separated by spaces on the next line.

3
4 6 7