Great question! Let’s dive into why IDEA still requires a restart when installing plugins, even though tools like Chrome or Java’s dynamic class loading seem to handle this seamlessly. It all comes down to how deeply plugins integrate with the IDE’s core architecture and the tradeoffs JetBrains has made for stability and performance:

• Deep Core System Hooks
  Unlike Chrome extensions that mostly interact with the browser’s UI or limited web APIs, IntelliJ plugins often tap into the IDE’s most foundational systems—things like code indexing, syntax parsing, debugger integration, or project configuration managers. These components are initialized early during startup and aren’t built to be reloaded on the fly. For example, a plugin adding support for a new programming language needs to register itself with the IDE’s syntax analysis engine, which is already tied to your open projects and running in memory.

• In-Memory State Consistency
  IDEA maintains tons of live state for your projects: open files, cached code analysis results, active debug sessions, and more. Loading a plugin dynamically mid-session could introduce conflicts if the plugin starts modifying or hooking into this state while it’s in use. A restart ensures the plugin loads alongside all core components from the start, eliminating any risk of inconsistent state.

• Complex Classloader Hierarchy
  While Java supports dynamic class loading, IDEA’s classloader setup is far more intricate. It uses a layered system to separate core IDE classes, plugin-specific classes, and your project’s classes. Plugins often depend on specific versions of IDE core libraries, and dynamically loading a plugin could lead to classpath conflicts or version mismatches that are nearly impossible to resolve without a clean start. Unlike simple Java applications, the IDE’s classloader environment is tightly coupled to its runtime state, making dynamic reloading risky.

• Legacy Architecture & Backward Compatibility
  IntelliJ has been around for over 20 years, and much of its core was designed before dynamic plugin loading was a standard expectation. JetBrains has added partial support for "hot" plugin installation (you might notice some newer plugins don’t require a restart!), but many older plugins and core systems still rely on startup-time loading to maintain compatibility with decades of existing code.

• Performance Prioritization
  Building a fully dynamic plugin system would require adding constant runtime checks, state synchronization, and reloading logic—all of which would introduce noticeable performance overhead. JetBrains has always prioritized keeping IDEA fast and responsive for daily development, so requiring restarts for most plugins helps avoid that ongoing performance hit.

It’s worth mentioning that JetBrains is gradually improving this—more plugins now support installation without a restart. But for deeply integrated tools, a restart remains the most reliable way to ensure everything works as intended.

内容的提问来源于stack exchange，提问作者AdamSkywalker