Just discard a dots and convert this binary number to decimal int32 number

https://en.wikipedia.org/wiki/IPv4

IEEE 754

10000000.00100000.00001010.00000001 is how you'd write the IP address 128.32.10.1 using the binary representation of numbers instead of decimal. 128, 32, 10, and 1 are simply the individual bytes of the number 2149583361 - explaining this further may somewhat spoil the task, so if you still don't understand how it works, you really should look up the relation between 32-bit integers and IPv4 yourself.

Can someone please explain to me why 10000000.00100000.00001010.00000001 is suddenly 2149583361? I cannot find sufficient information about this and I am lost.

error: cannot find symbol

symbol: class List

I wonder what the problem could be... Not a kata issue anyway.

WTF is one raising a kata issue while forgetting to copy imports from their IDE.

All the time I'm getting this:
"./src/main/java/CountingDuplicates.java:3: error: cannot find symbol
List charList = new ArrayList<>();
^
symbol: class List
location: class CountingDuplicates
./src/main/java/CountingDuplicates.java:3: error: cannot find symbol
List charList = new ArrayList<>();
^
symbol: class ArrayList
location: class CountingDuplicates
2 errors"

WTF?!