Introducing microservices into Java EE applications

Zahtevnost (poslovnih) aplikacij se povečuje dnevno. Aplikacije morajo biti skalabilne, delovati na več platformah hkrati (splet, pametni telefoni …), se povezovati in integrirati z zunanjimi storitvami, obdelovati velike količine podatkov v kratkem času, biti prilagojene za delovanje v oblaku … Kljub novim izzivom pa se razvoja takih aplikacij še vedno lotevamo na monoliten način, ki postaja čedalje manj primeren za sodobno, hitro rastoče (oblačno) okolje. Kot odgovor na to so se pojavile mikrostoritve, ki obljubljajo rešitev, vendar hkrati skrivajo veliko pasti. V diplomski nalogi primerjamo oba načina razvoja aplikacij in pokažemo, kdaj je primerneje uporabiti enega in drugega. Podrobneje se usmerimo v razvoj mikrostoritev ter predstavimo koncepte in orodja, ki nam lahko pri tem pomagajo. Prikažemo različne načine za vpeljavo mikrostoritev v javanske aplikacije in na koncu enega izmed njih uporabimo za preoblikovanje obstoječe monolitne aplikacije v ekvivalentno rešitev z mikrostoritvami.Complexity of (enterprise) applications and software is increasing daily. Applications are required to be scalable, to operate simultaneously on different platforms (web, mobile …), to connect and integrate with external services, process large amounts of data in short time, to work in the cloud … Despite new challenges, the development of this kind of applications is still being resolved in a monolithic manner, which is becoming less and less suitable for modern, quickly growing (cloud) environment. Microservices try to address this challenges, but while providing certain solutions they also present new problems. In this thesis both styles are compared and it is shown when one is more appropriate for use than the other one. More specifically, focus is given on development of microservices and concepts and tools of trade, that can help along the way. Different ways of introducing microservices in Java applications are presented, according to application requirements, and one of them is used to transform existing Java monolithic application to microservices