Computer Programming – Java Core concepts

Java concurrency and Thread safety

http://tutorials.jenkov.com/java-concurrency/thread-safety.html

Dynamic compilation and Classloading

http://www.javablogging.com/dynamic-in-memory-compilation/pliki/dynamiccompilation.zip

http://www.javablogging.com/dynamic-in-memory-compilation/

http://www.venishjoe.net/2009/10/dynamically-load-compiled-java-class-as.html

http://www.javabeat.net/the-java-6-0-compiler-api/

Serialization

http://www.javablogging.com/what-is-serialversionuid/

http://tutorials.jenkov.com/java-util-concurrent/executorservice.html

Java stack vs heap

https://www.guru99.com/java-stack-heap.html

Java Strings are Immutable Objects / String Concatenation is slow

http://tutorials.jenkov.com/java/strings.html

https://www.geeksforgeeks.org/java-string-is-immutable-what-exactly-is-the-meaning/

http://javarevisited.blogspot.com/2013/07/java-string-tutorial-and-examples-beginners-programming.html

http://www.xyzws.com/Javafaq/what-is-string-literal-pool/3

Java Character set and Encoding

https://www.baeldung.com/java-char-encoding

Base64 encodign

https://www.lifewire.com/base64-encoding-overview-1166412

Enums

http://howtodoinjava.com/2012/12/07/guide-for-understanding-enum-in-java/

Java general

http://www.programmerinterview.com/index.php/java-questions/java-whats-the-difference-between-equals-and/

Generics

http://ted-gao.blogspot.com/search/label/Java%20Generics

http://www.journaldev.com/1663/java-generics-tutorial-example-class-interface-methods-wildcards-and-much-more#generics-methods-constructors

Web application

Servlet specification

http://www.journaldev.com/1877/java-servlet-tutorial-with-examples-for-beginners