Sophie Sperner questions

• Java thread-safe write-only hashmap
• Anything faster than iterating ArrayList from the end side?
• Series of nested loops without recursion
• Find a supplement to a subarray of ints in Java
• Fastest strategy to form and sort an array of positive integers
• First Ever Java Program Incorrect Output
• Fastest Java HashSet<Integer> library [closed]
• Fastest way to recreate the ArrayList in a for loop
• Java best structure for 2D matrix of integers?
• How to run simple java app on amazon ec2?

Sophie Sperner answers