Incompatible Changes in IntelliJ Platform and Plugins API 2026.*

IntelliJ Platform 2026.1

AWT input event handlers no longer run under write-intent lock

Custom input handlers (KeyListener, MouseAdapter, etc.) no longer execute under the write-intent lock. If PSI or other write-intent-protected data needs to be accessed in these handlers, explicitly acquire a read action using ReadAction.nonBlocking().submit() or coroutine-based equivalents such as readAction {}.

Java Plugin 2026.1

The Java plugin has been split into several modules with their own classloaders. This shouldn't affect plugins that use standard <depends>com.intellij.java</depends> dependency. If a plugin depends on specific Java plugin modules directly, the dependencies should be updated to reference the new module names.