"import java.util.ArrayList;" is a java code. It should be declared in "code theme". People may miss the "import package" code part since it is not discriminated from the other parts as a code part. If they miss the whole code will complain just because of this simple mistake. This way people wouldn't miss the code to import the package.
* Adding basic Big O for ArrayList methods
I added average O(n) for basic methods in arraylist. This is important for every programmer to know.
* minor edits
* moved a few lines
SweeneyNew
msabitabrata
Karen Tobo
samsvo
Mallory Butt
Smruti Ranjan Rana
Sharon Gao
Mrugesh Mohapatra