Build GraphRAG in Java: extract entities and relations with Spring AI structured output, store them in Neo4j with a vector index, answer multi-hop questions with Cypher, and measure it against plain vector RAG on the same 35 documents. The extraction step is a rule-based stand-in, not an LLM, and the post says so.
Spring AI's audio API is its least-covered corner. Build a meeting-minutes generator on Spring AI 2.0.2: transcribe a recording, split files over the 25 MB upload limit at a silence, turn the transcript into typed action items with entity(), read them back with text-to-speech, and price an hour of meetings. Run against a local mock server and a stub chat model, with the failures captured.
30 JUnit 6 and Mockito 5 interview questions answered with tests that were actually run on JUnit 6.1.3, Mockito 5.24.0 and JDK 25: lifecycle, extensions, parameterized tests, mocks vs spies, verify, static mocking and flaky tests, each with captured output.
A beginner-first AssertJ 3.27.7 guide with real failure messages: fluent assertions, collections, exceptions, soft assertions and their traps, recursive comparison for DTOs, and custom assertions both hand-written and generated (including the javax.annotation fix the 2019 generator plugin needs on JDK 25). Every output is captured from a runnable companion module.
JDK 27 adds PEMDecoder and PEMEncoder (JEP 538, third preview; final in JDK 28 as JEP 542). Tested on JDK 27 and a JDK 28 early-access build: loading RSA, EC and Ed25519 keys for JWT signing, building a TLS server from PEM files, encrypted private keys, every failure message, and what changes when you drop BouncyCastle.
JDK 27's JEP 536 makes Java Flight Recorder redact command-line arguments, environment variables and system properties before they reach a recording. We plant seven fake secrets, record on JDK 25 and JDK 27, and find that defaults catch three and miss four. Includes custom filters, filter files, the glob and plus-prefix traps, and a CI leak scanner.
Hibernate 5.6.15 and 7.4.14 compared jar by jar and run side by side: removed APIs, annotation changes, the schema defaults that moved, and a cheat sheet of snippets verified on 7.4.14.
Spring Security 6.5.11 and 7.1.2 compared side by side: jars diffed class by class, Security 6 code compiled against both, and two probes run on both. What was removed, what moved to new artifacts, and what fails at startup.
JUnit 5.14.4 and 6.1.3 compared side by side: jars diffed class by class, the same tests run on both, and old APIs compiled against both. What was removed, what changed silently, and the order to upgrade in.
Reproduce a lost update with two threads, stop it with @Version, retry it, then compare PESSIMISTIC_WRITE, NOWAIT, SKIP LOCKED and a deadlock, with captured Hibernate 7.4.14 output.