Master the Core Principles and Architecture of Modern Java Backend Development

Core Principles of Software Development

Software development should follow several core principles: DRY (Don’t Repeat Yourself) to avoid duplicated work; KISS (Keep It Simple Stupid) to keep designs simple; YAGNI (You Aren’t Gonna Need It) to implement only necessary features; “Done is better than perfect” to iterate quickly; and choose the most suitable technologies rather than chasing hype.

Software Process

A software lifecycle includes project management (waterfall, spiral, agile, Scrum), test‑driven development (write unit tests before code), and continuous integration (automated build, test, and deployment using tools such as Jenkins or Quick Build).

Daily Development

Common tools include editors (Sublime Text, Vim, Emacs), source‑code version control (Git, Git Flow), and project management platforms (GitHub, Phabricator, ZenTao, Tower.im).

Runtime Environment

Backend services are deployed on Linux (CentOS, Ubuntu, Debian) using shell tools; application servers for Java are Tomcat and Jetty, while Nginx serves as a popular web server; load balancers such as LVS, HAProxy, and Nginx distribute traffic; virtualization and container technologies (VPS, VMware, Docker, OpenStack, Cloud Foundry) provide flexible environments.

Third‑Party Services

Typical external services include IaaS (AWS, Alibaba Cloud, UCloud), PaaS (Cloud Foundry, SAE, BAE, GAE), domain registration, CDN (Qiniu, UpYun, Alibaba Cloud), email (SMTP), SMS gateways, push notification platforms, and OAuth‑based open platforms (Weibo, WeChat, QQ).

Computer Science Fundamentals

Key knowledge areas are data structures (arrays, linked lists, hash tables, trees, graphs), algorithms (sorting, searching, complexity), design patterns (factory, singleton, observer, etc.), and computer networks (TCP/IP, HTTP/HTTPS, RESTful, OAuth2.0, SMTP).

Data

Cache: Redis with various data structures and eviction policies.

Databases: proper index usage, B‑tree indexes, differences between MongoDB, HBase, etc.

Search engines: full‑text and multi‑dimensional query handling.

Message queues: producer/consumer models, delivery semantics (at‑most‑once, at‑least‑once, exactly‑once).

Data storage and processing: offline batch processing vs. real‑time stream processing, handling data skew, windowing.

Data synchronization between operational databases and data warehouses.

Java

Core Java skills include IDEs (Eclipse, IntelliJ IDEA), language features (Java 6 syntax, Java 7 try‑with‑resources, Java 8 lambdas and streams), collections, utility libraries (Guava, Apache Commons, FastJson), bytecode tools (ASM, CGLIB), advanced topics such as concurrency, networking, serialization (Protobuf, Kryo), RPC frameworks (Thrift, Hessian, Dubbo, RMI), Java EE (Servlets, async servlet), build tools (Maven, Gradle), frameworks (Spring, MyBatis, Jersey, Vert.x, Spring Flux), and testing (JUnit, TDD).

JVM knowledge covers implementations (HotSpot, JRockit, J9, Dalvik, ART), class‑loading mechanisms (parent‑first, OSGi), runtime memory layout (program counter, heap, method area, etc.), Java memory model, garbage‑collection algorithms and tuning, and monitoring tools (jmap, jstack, jcmd, jconsole, btrace).

System Architecture

Applications evolve from monolithic to vertical (multiple independent services) and finally to distributed or micro‑service architectures. Service governance, scheduling, and maintenance become critical; Dubbo and Spring Cloud are common frameworks.

Deployment Architecture

A typical web deployment consists of LVS + Keepalived for layer‑4 load balancing, Nginx for layer‑7 reverse proxy, Tomcat as the Java container, Redis for caching, and MySQL in master‑slave mode for persistence. Alternatives include Redis Cluster, MySQL Cluster, etc.