✅ Network collection of interconnected devices that communicate with each other ☑️ Components of network Nodes: any device connected to network Links: connection between nodes ...

✅ What is Spring? open source application framework for JAVA Java platform that provides comprehensive infrastructure support for developing Java applications can build applcations from POJ...

✅ OSI 7 Layer Application: 사용자가 네트워크에 접속할 수 있도록 서비스 제공 Presentation: 세션 계층 간 주고받는 인터페이스를 일관성있게 제공 Session: 통신 시스템 사용자간의 연결 위한 유지 Transport: 두 호스트 사이 데이터 흐름 제공 Network: 패킷을 네트워크 간의 IP를 통...

Process 🆚 Thread Process: program running on memory has own address, resource Thread: work unit in process does not have independent address, resour...

✅ Mutable can be modified after initialization encapsulate: getter, setter, private, final field need to synchronize access for multi thread String Builder Stirng Buffer java.util.D...

✅ Garbage Collection? Garbage collection When Java is run on JVM, manage heap Stop the world, major GC 💡 https://soheeparklee.github.io/posts/JAVA_JVM/#%EF%B8%8F-garbage-collect...

✅ MVC Model / View / Controller 소프트웨어 설계 패턴 중 하나 앱을 모델, 사용자 인터페이스, 비즈니스 로직으로 구분하여 개발 ✅ MVC Design Pattern ✔️ Model business logic database respond to request for information fro...

✅ UI User Interface web design, layout font, color, space reactive, animation ✅ UX User Experience analyse experience with the page, make the web more comfortable and effici...

✅ Logging use log4j use different levels to express urgency of error ✅ ERROR Immediate solution required for program running ✅ WARN Need to be warned, but program is running unabl...

✅ API key User issues API key To use certain API, send key with request When requested, Application authenticated user information with key Respond to user with information from key ...