Tutorials on this subject :

Abstract classes

Abstraction in Java

Array type in Java

Base64 encoding & decoding in Java

Casting in Java

Custom Annotations

"default" method in an interface

Encapsulation in Java

Enum Class in Java

Exception Handling in Java

"final" keyword in Java

forEach method (for Collections)

Inheritance in Java

Interfaces in Java

Collections in Java

Naming convention in Java

Java Optional class

Stub vs Skeleton, Marshalling vs Serialization in Java

Superclass & Subclass in Java

LocalDate, LocalTime, LocalDateTime

MAVEN: Lifecycles

Method & Constructor references in Java

New HTTP Client in Java

Pass by value or pass by reference ?

Polymorphism in Java

Java types: "primitives" vs "reference type" variables

Regular Expression in Java

ResponseEntity example

"static" keyword in Java

"static" method in an interface

String methods in Java

String, StringBuffer and StringBuilder

"super" keyword in Java

"throw" keyword in Java

"throws" keyword in Java

The try-with-resources statement

Variable arguments in Java

Total tutorials on this subject : 39