GitHub repositories

Comparing hello-algo, java-design-patterns, Stirling-PDF, and mall

Four Java-centric GitHub projects observed on 2026-09-19 serve distinct purposes: algorithm education, design pattern reference, PDF manipulation, and e-commerce platform. This comparison outlines their reported scopes, concrete differences, and practical evaluation considerations.

AltAPIs Editorial · AI-assisted · automatically published after software checks; not human-reviewed

Programming illustration; not a screenshot of the products discussed. File:Programming code.jpg by Martin Vorel · CC BY-SA 4.0. Wikimedia thumbnail resize only; image remains under its original license.

Reported Purposes and Domains

The four projects target fundamentally different problem spaces. hello-algo presents itself as an animated, multi-language tutorial for data structures and algorithms ("动画图解、一键运行的数据结构与算法教程"), supporting 13+ programming languages including Python, Java, C++, and Rust. java-design-patterns focuses narrowly on implementing classic design patterns in Java. Stirling-PDF describes itself as a web-based PDF editing application usable "on any device anywhere." mall is a full-stack e-commerce system comprising a customer-facing storefront and an admin backend, built on Spring Boot and MyBatis with Docker deployment. These descriptions come directly from each repository's self-reported metadata observed on 2026-09-19.

Scope and Intended Audience

hello-algo and java-design-patterns are educational resources: the former teaches algorithmic thinking across languages, the latter catalogs pattern implementations for Java developers. Stirling-PDF targets end-users needing PDF operations (merge, split, convert, edit) via a self-hosted web interface. mall addresses developers and businesses building or studying production-grade e-commerce architectures, with modules for catalog, cart, orders, membership, promotions, CMS, analytics, finance, and RBAC. The fork-to-star ratios differ notably: java-design-patterns (27,374 forks / 94,706 stars) and mall (29,829 / 84,800) show higher forking activity relative to stars than hello-algo (15,519 / 130,268) or Stirling-PDF (8,914 / 92,529), suggesting the former two are more frequently used as starting points for derivative work or learning forks.

Implementation Stack and Deployment Model

All four list Java as their primary language, but their runtime models diverge. hello-algo provides algorithm implementations in 13+ languages; its Java component is one of many. java-design-patterns is Java-only by definition. Stirling-PDF runs as a containerized web application (implied by "on any device"), likely bundling a Java backend with a web frontend. mall explicitly states Spring Boot + MyBatis with Docker containerization for both frontend and backend services. Only mall and Stirling-PDF describe deployment artifacts (Docker); the two educational repos appear to be source-code libraries without packaged deployments. This distinction matters for evaluators: hello-algo and java-design-patterns are reference codebases, while Stirling-PDF and mall are runnable systems requiring infrastructure.

License Metadata and Maintenance Signals

License fields from the GitHub API show hello-algo, java-design-patterns, and Stirling-PDF all report "Other" (non-standard or custom), while mall uses Apache-2.0. The "Other" value requires direct inspection of each repo's LICENSE file to determine actual terms—this metadata alone does not convey permissions. All four were observed on the same date (2026-09-19) with firstSeenAt dates ranging from 2026-09-15, indicating they were already established in the dataset. No commit frequency, issue activity, or release cadence data is available from the supplied records, so maintenance health cannot be assessed from this snapshot alone.

Next Evaluation Steps

For each project, concrete next steps depend on the evaluator's goal. For hello-algo: verify language coverage matches your curriculum needs and check whether "一键运行" (one-click run) tooling exists for your target languages. For java-design-patterns: confirm pattern coverage (GoF, enterprise, etc.) and whether examples use modern Java idioms. For Stirling-PDF: test the self-hosted deployment, enumerate supported PDF operations, and assess resource requirements. For mall: review the module list against your e-commerce requirements, examine the Docker Compose/Kubernetes manifests, and evaluate the codebase's compatibility with your Spring Boot version. In all cases, consult the actual repository contents—README, LICENSE, issue tracker, and recent commits—since the supplied metadata captures only high-level descriptions and star/fork counts as of 2026-09-19.