Java 21 Language Core Intensive
Syntax refresh, records, pattern matching, and virtual threads with weekly mentor reviews on your exercises.
JPY 98,000
ViewSignals from recent cohorts
Mixed metrics—some from satisfaction surveys, some from delivery logs—so you can see how the studio operates week to week.
12
Open catalog modules spanning JVM, Spring, and data access
38%
Learners joining from non-Tokyo prefectures in the last intake survey
9.1
Average mentor note helpfulness (10-point cohort survey scale)
140+
Recorded micro-demos across all tracks (minutes vary by topic)
6
Partner organizations co-designing at least one lab per year
Inclusions you can verify
Transparent scope: repositories, rubrics, and office hours—without promising outcomes we cannot measure.
Reviewable artifacts
Every sprint ends with something linkable: PRs, ADR drafts, or profiling notes you can attach to a portfolio.
Mentor annotations
Feedback targets your diff, not generic slides—timed so it lands before the next assignment opens.
Paths, not vibes
Sequences spell prerequisites, expected hours, and what we deliberately skip so you can plan around gaps.
1,180
Pull requests reviewed across Surge Fluxon cohorts since 2019—each tied to a rubric, not anonymous clicks.
JVM depth with mentor loops
Build Java services with structured feedback, cohort accountability, and self-paced options when midnight coding fits better than live labs.
Browse catalog Trusted by internal upskilling pods at logistics and fintech teams
The flow — four beats
Horizontal rhythm instead of numbered circles; each beat has a deliverable.
01
Orientation
Tooling, repo access, and honesty about prerequisites.
02
Build slices
Small features with rubrics referencing hiring panels.
03
Review window
Mentor passes land before the next slice unlocks.
04
Retro & story
Narrate trade-offs for interviews and internal RFCs.
Featured modules
A rotating slice of the catalog—filters on the full listing page go deeper.
Spring Boot APIs for Production
Controllers, validation, OpenAPI, and deployment hygiene for services your team can operate overnight.
JPY 148,000
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JUnit 5, Mockito, and Contract Tests
Layered testing strategy from pure units to consumer-driven contracts without brittle suites.
JPY 72,000
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Concurrency and Structured Tasks
Executors, structured concurrency, and backpressure patterns for services that behave under load.
JPY 168,000
ViewFrom our cohorts
Varied lengths and formats—experience-first, tied to specific modules on this site.
The Spring Boot APIs for Production module on OpenAPI and Problem Details changed how our squad writes consumer-facing errors—clients finally get consistent JSON shapes.
— Leo Tanaka , Backend engineer · Osaka logistics API team
Concurrency lab’s structured task scope exercise made shutdown behavior visible; I borrowed the worksheet for our on-call primer.
Gradle Enterprise Builds: scan reading—not glamorous, but it funded our cache node.
OCA study studio’s timed mode exposed that I hemorrhaged minutes on generics; the whiteboard clinic fixed that faster than rereading guides. Still wish one mock exam had even hairier wildcard questions.
Bootcamp on-call simulation felt close to our incident retro format—useful stress, not theater. Client in enterprise integration.
Data Access with JDBC and jOOQ clarified when ORM magic hurt us; batch insert benchmark embarrassed an N+1 we defended for too long.