A phased OpenJDK migration is how you cut cost early and contain risk. Start with a pilot, move workloads in waves grouped by similarity, and isolate the residual, so savings begin long before the last workload moves.
Why phasing beats a single cutover
A migration that tries to move the whole estate at once concentrates risk into one event and delays every saving until the end. Phasing does the opposite. It contains any problem to a small group, lets your team learn and improve between waves, and starts shrinking your counted Oracle Java footprint from the first phase. Since the per employee Universal Subscription has been in force since January 2023, every workload you move off Oracle Java is a workload you no longer have to defend in a renewal. For the full method, see the OpenJDK migration playbook pillar.
The phases in order
- Inventory and sort: find every Oracle Java install and group workloads by risk and similarity.
- Pilot: move one low risk workload end to end and confirm the process.
- Waves: migrate groups of similar workloads, testing each before the next.
- Residual: isolate the few workloads that must stay on Oracle Java and license them narrowly.
Each phase has a clear exit test, so you never start the next wave until the current one is proven.
Phase one, the pilot
The pilot exists to prove the cutover process, not to move volume. Pick a workload that matters enough to be real but is low risk if it stalls, migrate it to a chosen OpenJDK distribution, test it functionally and under load, and run it in production while you watch. The pilot turns the abstract plan into a repeatable runbook your team can apply to every later wave. The safe mechanics of that cutover are set out in how to migrate off Oracle Java safely.
A sample phase plan
| Phase | Scope | Indicative timing |
|---|---|---|
| Pilot | One low risk workload | Weeks 1 to 3 |
| Wave one | Standard server side apps | Months 1 to 3 |
| Wave two | Apps needing vendor confirmation | Months 3 to 6 |
| Residual | Hard Oracle Java dependencies | Ongoing, licensed narrowly |
These timings are indicative and scale with the size of the estate. The shape, a small pilot followed by widening waves, holds at any size.
Capture the saving as you go
The financial point of phasing is that cost falls during the project, not only at the end. As each wave moves off Oracle Java, your defensible counted footprint shrinks, which strengthens your hand at the next renewal even if the migration is not yet complete. A documented, in progress migration is itself negotiating leverage. The way that residual becomes a smaller negotiation is part of the OpenJDK migration playbook.
Keep evidence at every phase
Each phase should leave a dated record of what moved, when, and to which distribution. That trail does two jobs at once. It keeps the project governable, and it builds the evidence base that defends you if an LMS audit arrives with its three year lookback. Treat documentation as part of the work of every wave, not an afterthought.
The buyer side takeaway
Plan the migration in phases: inventory and sort, a proving pilot, widening waves, and a narrowly licensed residual. Phasing contains risk, lets your team improve as it goes, and starts cutting cost from the first wave. Keep dated evidence throughout for both governance and audit defense. Download the field guide below to build your phase plan.
Download the OpenJDK Migration Field Guide
A buyer side playbook for CIOs, procurement, and general counsel planning a move off Oracle Java. Trade a work email, get the guide and The Java Audit Brief.
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