Capgemini Java Fullstack/Microservices Developer interview questions

Core Java- use of streams in java What happens if I try to access a variable(which is declared outside) inside a .forEach block? Is it possible? Yes/no -Why? Hashmap vs concurrent hashmap and it’s workings. How many threads can access a concurrent hashmap at a time? Is it possible to modify a array-list while iterating it? Is there a way to do it? Some coding questions on overriding and exception handling concepts