Java Basics: Beyond the Fundamentals

Describe the end-to-end lifecycle of a Java program: source compilation by javac, .class file generation, class loading, and JVM execution.

Explain the structure of a .class file, including the magic number, constant pool, and field/method tables.

Identify and describe the core JVM subsystems: class loader subsystem, runtime data areas, and execution engine.

Explain the class loading phases: loading, linking (verification, preparation, resolution), and initialization.

Implement a simple custom class loader to dynamically load a class from a specified path.

Compare common GC algorithms (e.g., Serial, Parallel, G1, ZGC) and the trade-offs each makes.

Identify common GC tuning flags (-Xmx, -Xms, -XX:+UseG1GC) and explain their purpose.

Explain how primitive types and their wrapper classes differ in memory storage and behavior.

Compare StringBuilder and StringBuffer in terms of internal array management, resizing strategy, and thread safety.

Explain Java's pass-by-value semantics for both primitive types and object references with precise examples.

Describe the Java thread lifecycle and all thread states (NEW, RUNNABLE, BLOCKED, WAITING, TIMED_WAITING, TERMINATED).

Identify and explain race conditions with code examples and demonstrate prevention strategies.

Describe explicit locks (ReentrantLock) and their advantages over intrinsic locks (e.g., fairness, tryLock, interruptibility).

Explain the purpose of the Executor framework and differentiate between common thread pool types (Fixed, Cached, Scheduled).

Demonstrate with a code example how compiler, JIT, or CPU instruction reordering can lead to incorrect behavior in a multithreaded context.

Use the Reflection API to inspect the structure of classes, methods, and fields at runtime.

Use the Reflection API to dynamically create object instances and invoke methods.

Implement a basic dependency injection container using reflection to manage object creation and wiring.