Java Web Interview Experience and Essential Knowledge Checklist

The author, a software designer at a state‑owned enterprise working mainly on operating systems, drivers, and tool software in C/C++, decided to seek a new opportunity and secured an interview with Alibaba for a Java Web position.

During the phone interview, basic topics such as the differences between HashMap and Hashtable, servlet fundamentals, and Java multithreading were discussed, but the author was stumped by AOP concepts.

Despite some unanswered questions, the author was invited to an on‑site interview in Wuhan, where two simple algorithm problems (string conversion) were solved, revealing rusty knowledge in UML class diagrams, database schema design, and HTTP status codes; this prompted a rapid review of Spring, Struts, Hibernate, and Java Web analysis literature.

The second interview focused more on the résumé and personal experience, covering project details, B2B business views, and a question about willingness to work on Alibaba Cloud; interviewers were generally satisfied, noting only limited work experience.

The final interview concluded with a positive phone call indicating a likely offer, leaving the author awaiting the official confirmation.

Reflecting on the experience, the author decided to organize essential Java Web knowledge, presenting the following checklist:

1. Underlying

JVM architecture and operation principles, including the Java Memory Model, various GC algorithms, and ClassLoader loading mechanisms.

JVM monitoring and tuning to gain deep insight into program runtime behavior.

Java multithreading concepts, thread safety, and strategies to avoid concurrency issues.

I/O models (BIO/NIO), their relation to Linux synchronous/asynchronous I/O, and why mechanisms like epoll are used.

2. Servlet

Servlets are server‑side Java programs that typically extend HttpServlet and implement init, doGet, doPost, or service methods. Their lifecycle includes initialization, request handling, and destruction.

Beyond theory, practical ability requires understanding servlet containers (e.g., Tomcat), including manual deployment via command line to grasp compilation, packaging, and deployment processes.

Reference: "Servlet and JSP Core Programming".

3. Frameworks

Spring

Spring is a powerful, "lightweight" Java framework that simplifies development by replacing hard‑coded configurations with declarative setups, achieving module decoupling. Its core components include data access, remote communication, AOP, and the core container.

Figure 1 Spring Architecture

The three main pillars of Spring are:

IoC : Inversion of Control, where the container manages object creation and configuration.

Dependency Injection : Automatic injection of required dependencies, promoting loose coupling.

Aspect‑Oriented Programming (AOP) : Separation of cross‑cutting concerns from business logic.

Reference: "Spring in Action".

Hibernate

Hibernate is a widely used ORM framework for data persistence, though many developers now prefer MyBatis for its flexibility.

Typical Hibernate workflow: load configuration → create StandardSessionFactory → open Session → begin Transaction → perform persistence operations → commit and close.

Figure 2 Hibernate Workflow

Understanding ORM: it bridges the gap between object‑oriented models and relational databases.

Hibernate defines four object states: transient, persistent, detached, and removed, with state transitions illustrated below.

Figure 3 Hibernate Object State Diagram

Struts 2

Struts, one of the earliest Java web frameworks, aims to simplify development by providing a unified action‑based architecture.

Key concepts include Action execution, interceptor mechanisms, the ValueStack, and OGNL expression language.

Reference: "Struts in Action".

4. HTTP

Mastering HTTP is essential for web developers. Important topics include header formats, status code meanings, HTTPS implementation, B/S architecture, cookie and session principles, and RESTful API design.

5. Design Patterns

While the classic "Gang of Four" patterns are numerous, true understanding comes from applying them in real projects and questioning their usage.

6. Summary

Web development extends beyond coding to deployment concerns such as CDN, load balancing, and other infrastructure topics. Good habits—like proficiently drawing UML class and interaction diagrams—help avoid common mistakes. The author acknowledges remaining gaps and commits to continued learning to make the most of the interview opportunity.

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