Modernization track · Advanced · self-paced ~35h with labs (6 days as a cohort) · prerequisite: CS510 (or Spring Boot experience), CS530 Sessions 1–3 (or equivalent testing literacy) and CS100
The rewrite done honestly: read CardDemo’s COBOL as a specification, extract its business rules into a register, design bounded contexts and a domain model with invariants, build Spring services and a rethought batch and event spine, prove behaviour parity through a scenario-driven contract suite run against SteelFrame with every difference declared by design and owned, and strangle one function with the mainframe still the system of record — using an assistant where it helps and the oracle to judge. 44 short videos (about 5h30m). Every lesson refers back to the AWS CardDemo application running live on SteelFrame — its COBOL source, batch jobs, CICS screens and VSAM/DB2 data — and every lab starts on the mainframe side: you run the legacy program under your own user to produce the golden, then make the Java match it.
Self-paced available Cohort
Open for enrollment now. The lesson videos for this course are in production — release order across the track: CS510 → CS520 → CS530 → CS521 → CS535 → CS500 → CS550 → CS525 → CS540 → CS545 — and every session below is published as its lessons and lab now and marked Coming soon until its videos are released.
Plans: Free individual at no cost, or Paid individual at $349 per course, one-time — code review, extra exercises, grading and priority support.
Every session ends in a lab on your own environment. Labs are machine-checked against expected outputs — you and your L&D team always know exactly where you stand.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. When rewrite wins and when it kills — Commonwealth Bank against TSB, Co-op/Finacle and Queensland Health — opening on CardDemo live on 3270; behaviour parity vs byte parity, the same transaction judged by equiv and by contract, and who owns a difference; the method — extract, model, build, prove, strangle — mapped onto the real chain in SDSF; the tooling market (ADDI, CAST, SMART TS XL, Google MAT, AWS reimagine) and what analysis_graph finds and cannot.
LAB Checkpoint 0: run CT02 through twenty inputs on 3270 and list every observable behaviour of COTRN02C — messages, outcomes, side effects, cursor — as the register’s raw material.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. Reading COBOL as a specification — conditions, computations, edits, side effects, ordering — with COTRN02C’s validations becoming rules R01–R11 in EDIT; the analyst’s tools — analysis_impact and search_source following ACCT-CURR-BAL across five programs; the rule register as data the grader reads, every entry’s source lines opened in BROWSE; the rule hidden in a copybook VALUE clause and in a JCL PARM.
LAB Checkpoint 1: 25 rules of the posting programs, copybooks and JCL registered with SteelFrame-run examples; coverage against the harness’s rule list at least 90%.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. Scenario files from captured transactions — cics_run_script, run_capture, export_state — one scenario end to end; contract tests with per-field tolerance and an owner, a passing and a failing case read; property tests from rules with the credit-limit rule exercised on SteelFrame first; the declared-difference register — wording, layout, ordering, timing — with one declaration refused.
LAB Checkpoint 2: forty scenario tests across the account and transaction rules, wired into mvn verify, all red against the empty domain.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. Bounded contexts — accounts, cards, transactions, users — drawn from the call graph and corrected by the register; entities, value objects and invariants with Money’s scale read off the packed field in hex; aggregates, transactions and idempotency keys against a double submit observed on 3270; ArchUnit rules that encode the model, mirroring the program boundary in the COBOL.
LAB Checkpoint 3: the domain model green on unit tests seeded with the captured scenarios’ values; ArchUnit green.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. Application services, REST contracts and OpenAPI designed from the rules with the COMMAREA and screen fields as the inventory; validation ladders rewritten — same outcomes, new wording, declared; the security model that replaces USRSEC beside RACF; persistence from the model with the migrated data reconciled against decode_records.
LAB Checkpoint 4: account and card services pass the online scenario suite under contract; every declaration owned.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. Which batch survives (interest, statements, backups) and which becomes event-driven (posting), classified on the real chain in SDSF; Spring Batch for the survivors and the CA-7/Control-M definitions as an Airflow-class DAG; events and the outbox with the MQ trigger as precedent; the nightly total that no longer matched because posting moved to real time — declared difference or defect, decided by the reconciliation.
LAB Checkpoint 5: real-time posting plus the interest job produce category and account totals equal to the COBOL cycle’s for the same day.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. Routing by function with SteelFrame as system of record; reading through the cics_link façade while writes stay on CICS; the flip per function and the overlap reconciliation against read_records; the rollback drill under 3270 traffic.
LAB Checkpoint 6: card list served by Java, writes still on CICS, hourly reconciliation green for the simulated day, rollback proven.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Four videos. Assistants for rule extraction and test generation with the review checklist, an extraction run over MCP beside the source; the generated requirement that was wrong — "rounded half-up" against a COBOL that truncates — caught by the contract test seeded from a SteelFrame run; the evidence trail an auditor wants from an AI-assisted rewrite.
LAB Checkpoint 7: the COBIL00C bill-pay rules extracted with your assistant, reviewed, registered and proven by contract scenarios captured on SteelFrame, with the evidence trail.
Coming soon The videos for this session are being produced; its lessons and lab are published here now.
Five videos. Reading an unseen domain service beside the CardDemo program it came from; the hidden variant with three seeded behaviour changes found by the contract suite and reproduced; the parity report — rules covered, contracts green, differences declared and owned; portfolio and interview with live frames; the certificate.
LAB Checkpoint 8 and capstone: three behaviour changes found by the suite before any COBOL is read, reproduced, suite green; the parity report; the 30-question reading check (80%).
CobolStack Certificate — Rewrite & Re-architecture (CS525) is issued from the lab harness’s own record of your runs — not from attendance. To earn it you must clear every gate below:
The certificate attests that you can rewrite a mainframe application from extracted business rules into a Spring domain and prove behaviour parity against the legacy running beside it — the honest version of what "reimagine" programmes promise — with every difference by design, owned and evidenced.
Your seat is a private, full z/OS-compatible environment with the AWS CardDemo estate (COBOL, JCL, CICS/BMS, VSAM, DB2) and the SteelFrame oracle tools (run_capture, export_state, cics_run_script), beside your own Java 21 + Maven + PostgreSQL toolchain; Spring Boot 3, Flyway, ArchUnit, the course contract grader in the browser — nothing to install, snapshot and reset per exercise. By the end of the course the lab harness will have verified: eight checkpoints — every observable behaviour of COTRN02C listed, 25 posting rules registered with run examples, forty contract scenarios captured, a domain model with invariants and ArchUnit rules, account and card services passing the scenario suite, posting and interest matching the COBOL cycle’s totals, card list strangled with rollback, a rule set extracted with an assistant and verified — and the capstone on a hidden CardDemo variant whose three seeded behaviour changes your contract suite must find.