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Java

Core Java topics now live under this parent section so language, JVM, and standard-library material stays grouped separately from Spring and platform topics.

What You'll Find Here

DomainDescription
Core JavaLanguage basics such as variables, operators, control flow, arrays, strings, and methods.
Object-Oriented ProgrammingClasses, objects, inheritance, polymorphism, abstraction, records, and sealed classes.
Java Type SystemPrimitives, references, generics, wildcards, type erasure, and inference.
Core APIsFoundational JDK classes such as Object, String, Math, wrappers, and utilities.
Collections FrameworkLists, sets, maps, iterators, ordering, and collection utilities.
ExceptionsException hierarchy, checked vs unchecked exceptions, and handling strategies.
Functional ProgrammingLambdas, functional interfaces, streams, and method references.
Multithreading & ConcurrencyThreads, synchronization, concurrency utilities, and virtual threads.
I/O & NIOFiles, streams, buffers, channels, serialization, and NIO APIs.
JVM InternalsClass loading, memory management, JIT compilation, and garbage collection.
AnnotationsBuilt-in annotations, custom annotations, meta-annotations, and processing.
Java ModulesThe Java Platform Module System, module-info.java, and encapsulation boundaries.
Java EvolutionLanguage and platform changes across Java versions.
Design PatternsCommon design patterns expressed with Java examples.
CheatsheetsQuick-reference pages for common Java APIs and concepts.

Learning Path

  1. Start with Core Java to re-establish language fundamentals.
  2. Then read Object-Oriented Programming and Java Type System to rebuild the conceptual model most other topics rely on.
  3. Continue with Core APIs, Collections Framework, and Exceptions for day-to-day Java work.
  4. Move into Functional Programming, Multithreading & Concurrency, and I/O & NIO once the basics are solid.
  5. Finish with JVM Internals, Java Modules, Java Evolution, and Design Patterns for deeper reasoning and interview depth.
  • Spring Framework — core Spring concepts build on Java object modeling, annotations, and reflection.
  • Testing — unit and integration testing depend on solid Java language and library fundamentals.
  • Build Tools — Maven and Gradle manage the Java code in these subdomains.