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Hand-written tutorials, ordered as a recommended learning path.

1. 21 Classes Design Java classes that hold state and behavior cleanly. Constructors, encapsulation, static vs instance, records, and the equals plus hashCode contract. 5 min read →
2. 22 Collections Pick the right Java collection by performance and semantics. ArrayList vs LinkedList, HashMap vs TreeMap, immutability, and iteration without surprises. 5 min read →
3. 23 Control Flow Every branching and looping construct in modern Java, including switch expressions and pattern matching, with examples that mirror real code. 5 min read →
4. 24 Exceptions Throw, catch, and chain exceptions without leaking abstractions. Checked vs unchecked, try with resources, custom exceptions, and rules that scale. 5 min read →
5. 25 Generics Write Java generics that compile and read well. Type parameters, bounded wildcards, PECS, type erasure, and how to avoid raw types in your own code. 5 min read →
6. 26 Inheritance Use extends, super, and method overriding without painting yourself into a corner. When to inherit, when to compose, and how sealed types help. 5 min read →
7. 27 Install Java Install a modern JDK, verify the toolchain, and ship your first Java program from the command line without an IDE doing the magic for you. 4 min read →
8. 28 Interfaces Choose between interfaces and abstract classes with confidence. Default methods, sealed interfaces, functional interfaces, and concrete decision rules. 5 min read →
9. 29 Streams Transform collections with lambdas and the Stream API. Map, filter, reduce, collectors, parallel streams, and the pitfalls of lazy pipelines. 5 min read →
10. 30 Variables Master Java primitives, reference types, literals, and casting. Know exactly what each type costs and where overflow and precision will bite you. 5 min read →