Stage 1 · Lesson 8 of 8
Modern Java: records, sealed types and interfaces
Java has changed a lot since the textbooks many courses still use. give you a compact, data class with equals, hashCode and toString written for you. Sealed and classes list every allowed subtype, so a switch over them can be checked by the compiler for missing cases.
Interfaces can have default methods, and lambdas turn one-method interfaces into short expressions. Together these make many classic patterns shorter: a is often a lambda, and a visitor is often a switch over a . Learn them on a current long-term support release, and read the Dev.java tutorials for your version.
Common trapfollowing old Java tutorials that write fifty lines of getters, setters and equals for what is now a one-line record.
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Resources for this stage
Start with· follow one of these
- CoursePaidGrokking the Object Oriented Design Interview
Design Gurus · Intermediate · Subscription
Its opening chapters teach the four OOP ideas applied inside real designs, with UML and running code
- CourseFreeMIT 6.102: Software Construction
MIT · Intermediate
Free MIT readings: Abstract Data Types, Rep Invariants and Interfaces and Subtyping are this stage at university depth