Sanghun Lee

Backend Engineer interested in event-driven architecture, backend reliability, and AI/RAG systems.
I like building systems whose behavior can be explained with tests, fault injection, and observable evidence.

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Tech Stack

Language :

Back-End :

Database :

Messaging :

Deployment / Observability :

AI / Automation :

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Experience

• All4Land Software Engineer Intern (2025.09 - 2025.12)
  • Billing system enhancement and infrastructure improvement project
  • Backend development with Java, Spring Boot, Oracle, and MyBatis

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Projects

• E-Commerce Platform (2026.02 - 2026.04)
  Java/Spring Boot MSA for order, payment, product, and member domains.

• AutoNotify with Qualcomm (2025.03 - 2025.06 / 2025.12 - 2026.02)
  On-device AI vehicle detection and notification pipeline.

• Solomon-AI (2024.06 - 2024.08)
  Legal-grounded conversational AI service with RAG and streaming responses.

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Open Source Contribution

• ✅ Merged Spring Integration #11247
  Fixed JdbcMetadataStore.putIfAbsent() looping forever under MySQL REPEATABLE READ by re-reading with the locking query only when the non-locking re-read comes back empty, so it observes the same state the insert did.

• 🟡 In Review Spring Session #3870
  Fixed SortedSetRedisSessionExpirationStore cleanup to touch the session's expires shadow key so Redis keyspace expiration events fire and SessionExpiredEvent/SessionDeletedEvent are published.

• 🟡 In Review Hibernate ORM #13104
  Fixed ScrollableResults#setRowNumber(0) in the collection-fetch implementation to position before the first row instead of throwing, matching the standard implementation.

• 🟡 In Review Redis Lettuce #3843
  Fixed Master/Replica SCAN/HSCAN/SSCAN/ZSCAN under ReadFrom by pinning cursor continuations to the issuing node so full scans stop dropping keys.

• ✅ Merged Spring Data Relational #2324
  Fixed Spring Data JDBC mapping so unordered Collection child elements can be saved and loaded without a key column.

• ✅ Merged OpenSearch Java #2033
  Added Testcontainers-backed OpenSearch startup for integration tests, removing the Docker Compose pre-run step.

• 🟡 In Review Docker CLI #7117
  Added an IP masquerading example for custom bridge networks.

• 🟡 In Review Redis Lettuce #3803
  Updated Kotlin coroutine APIs, docs, generator output, and regression tests.

• ✅ Merged Redis Lettuce #3809
  Fixed a skipped JFR event recorder test so it runs in Maven, and replaced an outdated no-JFR event fixture.

• ✅ Merged Apache Lucene #16300
  Analyzed OOM in TestTermInSetQuery.testDuel and reduced query-cache/TopDocs heap pressure.

• ✅ Merged OpenSearch Java #2017
  Added a Document Lifecycle guide and runnable sample.

• ✅ Merged Spring AI #4220
  Added manageDocumentIds support for AWS OpenSearch Serverless document ID handling.

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Activity

• Techeer member (2024.02 - Present)
• Tech talks on async queues, Docker, and backend fundamentals
• SQLD certified through 2027.12.12