JAVA-SE21: Java SE 21 Programming

Ecosystem overview: Understanding the JVM, JDK, and JRE architecture.Environment configurations: Setting up the environment variables and compilation tools.Basic syntax: Working with primitives, data types, and local variable type inference (var).Operators: Evaluating arithmetic, relational, and boolean precedence rules

Decision making: Writing standard if/else and advanced switch statements.Loop constructs: Utilizing while, do-while, and standard/enhanced for loops.String processing: Manipulating text blocks, StringBuilder, and the unified repeat() method

Objects: Instantiating fields, constructors, and managing object lifecycles.Memory mechanics: Analyzing parameter passing, stack vs. heap allocation, and garbage collection.Encapsulation: Enforcing access modifiers, overloading methods, and designing immutable objects

Polymorphism: Extending classes, method overriding, and dynamic type casting.Type variants: Implementing interfaces, functional interfaces, and custom enum types.Modern typing: Structuring immutable data with record classes and configuring restrictive sealed hierarchies

Arrays: Initializing and managing single- and multi-dimensional matrices.Collections framework: Leveraging lists, sets, maps, and new Sequenced Collections.Lambda expressions: Writing concise functional code and using built-in predicates.Stream API: Processing pipeline data using operations like filters, mapping, reductions, and parallel sorting

Error mechanics: Managing checked vs. unchecked exceptions.Resource safety: Implementing try-catch-finally structures and automated try-with-resources.Injection defense: Writing clean code to block SQL and scripting vulnerabilities

Platform threads: Deploying classic multi-threaded synchronization and the ExecutorService framework.Virtual threads: Implementing massive concurrency for scalable, I/O-bound workloads.File I/O: Interfacing with files, directories, and file systems using JDK NIO.2 specifications.Database connectivity: Executing basic CRUD transactions via JDBC drivers.Modular programming: Building, packaging, and deploying applications through the Java Platform Module System (JPMS)