JEP 479: Remove the Windows 32-bit x86 Port

Summary

Remove the source code and build support for the Windows 32-bit x86 port. This port was deprecated for removal in JDK 21 with the express intent to remove it in a future release.

Goals

• Remove all code paths that apply only to Windows 32-bit x86.

• Cease all testing and development efforts targeting the Windows 32-bit x86 platform.

• Simplify the JDK's build and test infrastructure.

Non-Goals

• It is not a goal to remove or change 32-bit support for any platforms other than Windows.

• It is not a goal to remove either code or support for Windows 32-bit in previous releases.

Motivation

• Allow contributors in the OpenJDK Community to accelerate the development of new features and enhancements that will move the platform forward.

• The implementation of JEP 436 (Virtual Threads) for Windows x86-32 falls back to the use of kernel threads and therefore does not bring the expected benefits of Project Loom.

• Windows 10, the last Windows operating system to support 32-bit operation, will reach End of Life in October 2025.

Description

• Find and remove all code paths in the code base that apply only to Windows 32-bit.

• Modify the JDK build system to remove support for compiling on Windows 32-bit platforms, and halt testing activities for this architecture.

• Update the JDK documentation to reflect the removal of Windows 32-bit support, and publicize this change so as to ensure a smooth transition for users and developers.

Risks and Assumptions

Some users may still rely on 32-bit Java applications on Windows. This change requires Java applications running on 32-bit Windows to migrate to a 64-bit JDK and Windows environment, or else remain on legacy versions of the JDK, prior to JDK 23, which still include 32-bit support. Transition guidance and support by distributions and vendors of JDK binaries will be critical.