Angular ------- 1. Pass data between components 2. Pass data if there is no relation between components 3. how to get the query string in component 4. RxJs in Angular 5. how you implement unsubscribe method in observable Java --- 1. Feature used in Java 8? 2. Completable Future? Spring Boot ------------ 1. Connect two dbs & use one instance at runtime 2. if there is 3 service with 3 DB & if one goes down, how to rollback the operation