[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8},"actionData","errors","root",{"_28":-5,"_38":-5,"_39":40,"_41":42,"_43":44,"_45":46,"_47":48,"_49":50,"_51":52,"_53":54,"_55":56,"_57":58},"routes/_store+/_readers+/email_author.$slug/route",{"_9":10,"_11":-5},"book",{"_12":13,"_14":15,"_16":17,"_18":19,"_20":21,"_22":23},"currentUser","id","Z2lkOi8vbGVhbnB1Yi9TdG9yZTo6Qm9va1Byb2R1Y3QvODM4MTQ","title","JDK8 to 25 - A practical migration guide","state","published","contactAuthorMethod","email","aboutText","

Moving a Java application from JDK 8 to a modern JDK is not a simple version bump. Across the releases in between, APIs have disappeared, defaults have changed, internals have been locked down, build tools have moved on, and code that still compiles can behave differently at runtime.

This book is a practical guide to finding those problems before they find you. It explains the tools you can use to assess an existing application, maps the important changes across JDK releases, and provides a catalogue of real migration failure modes: what they look like, why they happen, how to detect them and what to do about them.

The focus is on getting from JDK 8 to JDK 25, while also showing what JDK 26 changes next. The examples are built around real JDK behaviour and are designed to be used as much as read. You can work through the guide as part of a planned migration, or jump straight to the failure, exception or behaviour you are trying to understand.

The aim is simple: replace “let’s upgrade it and see what breaks” with a migration you can investigate, test and manage.

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Kick off your book project, get started with GhostAI, get better at marketing, or spend the day doing all three! Free live workshops on Zoom. Saturday, June 27, 2026.

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