Write a Java program that launches 1000 threads. Each thread adds 1 to a variable sum that initially is 0. You need to pass sum by reference to each thread. In order to pass it by reference, define an Integer wrapper object to hold sum. Run the program with and without synchronization to see its effect.

Write a method public static string getdigits(string phonenumber) that takes an 11-character phone number written with any combination of 11 uppercase letters, lowercase letters and/or digits, and zero or more hyphens, and which returns the digits that a person would have to press on a cell phone to dial that phone number. we will use the mapping of letters to digits given at en.wikipedia.org/wiki/telephone_keypad# /media/file: telephone-keypad2.svg you may assume that the string parameter phonenumber contains some combination of exactly 11 uppercase letters, lowercase letters and/or digits, but that any number of hyphens may be present. you can assume that a hyphen will not appear as the first or last character of the string. do not assum