Understanding Java for beginners

Webend Ankara
https://www.youtube.com/watch?v=8qPz0X4F8R4

Transcript

1. Understanding Java for beginners Osman Üngür, webend, 2016
2. Who i am? • software developmer with system-administration background over 10 years • mostly writes Java and PHP • also working about infrastructure design, system automation, deployment and monitoring • obsessed about clean, well structured, maintainable and scalable architectures. • loves open source github.com/o
3. My career path • in 2002, i started to learn fundamentals of Linux network and security. After that, for years i sold and managed dedicated servers and shared web hosting • after the Linux administration story, in 2005 dived into PHP and learned principles of object-oriented-programming • in 2010, i'd started a company which is uses Java, Spring Framework and SOA architecture. Ported thousands of line PHP code to Java and experienced with very large traffic. Slowly i'd embraced Java, NoSQL, RESTful and micro-services architectures • Since August 2015, i'm working as a freelance consultant, trainer and developer. I'm an active contributor and author of open-source projects.
5. Topics • what is Java (Platform)? • internals • popularity • use cases • questions?
6. Java Platform • general-purpose computer programming language • multi-thread concurrent • object-oriented (class-based) • compiled • static, strong, safe, error free
7. there were five primary goals in the creation of the Java language: • it must be "simple, object-oriented, and familiar". • it must be "robust and secure". • it must be "architecture-neutral and portable". • it must execute with "high performance". • it must be "interpreted, threaded, and dynamic".
8. • it is intended to let application developers "write once, run anywhere" (WORA) • compiled Java code can run on all platforms that support Java without the need for recompilation • Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture
9. • java syntax borrows heavily from C and C++, but object-oriented features are modeled after Smalltalk and Objective-C. • several languages have been designed to run natively on the JVM, including Kotlin, Scala, Clojure and Groovy.
10. Internals
11. JVM (Java Virtual Machine) • "virtual machine" that executes Java bytecode programs • garbage collection • optimizations (compile time and run time)
13. garbage collection • cleaning unused java objects • cleaning memory • minor gc (young) • major gc (full)
14. JIT (Just in time) • compile byte code to native code • compile as rules of optimization • at execution / installation
15. Hotspot • adaptive optimization in runtime (profiling) • method inlining • dynamic deoptimization • dead code branchs elimination
16. Popularity • java is used in a wide variety of computing platforms • from embedded devices and mobile phones to enterprise servers and supercomputers
18. source: TIOBE Index
21. you can write • desktop applications • web applications • mobile applications • games
22. • microservices • restful applications • big data technologies • embedded applications • android apps • integrated development enviroments
23. • financial services • trading engines • online banking • telecommunication • e-commerce • portals
24. What we learned? • what is Java (Platform)? • internals • popularity • use cases
25. Questions? • github.com/o • osman.ungur.org • twitter.com/oungur