Introduction to Java
6 Topics
1
What is Java?
An in-depth exploration of Java's architecture, design philosophy, execution model, and memory management.
Heavily tested on fundamental concepts: compilation vs runtime, bytecode, Platform Independence (WORA), and memory safety.
2
History of Java
The history and evolution of Java from Sun Microsystems' Oak language to modern Oracle Java 21 LTS, detailing major feature milestones.
Useful for senior interviews to show depth of language knowledge (e.g., choosing Java 8 vs 11 vs 17 vs 21 features).
3
JDK, JRE, and JVM
A comprehensive breakdown of the Java Platform architecture, detailing the exact role of JDK, JRE, and the internals of the JVM.
Classic interview topic. Interviewers expect deep understanding of ClassLoaders, JIT compiler, Garbage Collection roots, and memory areas (Heap vs Stack).
4
Features of Java
Deep dive into the classic Java Buzzwords: Object-Oriented, Platform-Independent, Secure, Robust, Multi-Threaded, and High-Performance.
Critical for architectural interviews. Questions explore why Java is secure (sandbox, bytecode verifier) and why it is robust (no pointers, automatic GC).
5
Your First Java Program
Write, understand, and dissect every token of a standard "Hello, World!" Java application.
Tests absolute fundamentals. Expect questions asking why main is static, whether it can be private, and why it returns void.
6
Compilation and Execution Process
A comprehensive look under the hood at how a Java source file (.java) is compiled into bytecode and executed inside the JVM.
Intermediate-to-advanced interviews focus on the internals of bytecode, compiler phases, linking, classloading phases, and execution strategies.