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Gradle 9.7 Parallel Configuration Nearly Doubles Android Sync Speed

By 恋猫de小郭 ·
Read original on juejin.cn ↗ Google Translate ↗ Alt translation

For teams maintaining large Android monorepos with hundreds or thousands of modules, this is a direct build-time win that requires no code changes beyond removing cross-project state access. The feature also signals that Gradle, Google, and JetBrains are jointly hardening the toolchain's concurrency model, which will eventually benefit every Android developer by default.

Summary

The configuration phase of a Gradle build has long been a bottleneck because modules could freely read and write each other's mutable state, making safe parallel execution impossible. Gradle 9.7.0's Isolated Projects feature, built in collaboration with Google and JetBrains, enforces a strict boundary: each project can only touch its own state. This constraint turns configuration into an embarrassingly parallel workload. In a 5,000-module monorepo, Gradle's own benchmarks show sync times dropping from over five minutes to under three. The feature is built on top of the Configuration Cache infrastructure and is now incubating, with plans to become the default mode. Older projects with custom scripts or plugins that rely on cross-project access will break when this is enabled.

Takeaways
Gradle 9.7.0 promotes Isolated Projects from experimental to incubating, with plans to make it the default mode.
Each Gradle Project's configuration logic is now restricted to its own mutable state, forbidding direct reads or writes to other projects.
Immutable properties like a project's name, path, and directory remain readable across boundaries.
Enabling Isolated Projects automatically turns on Configuration Cache; disabling the cache causes a build error.
Gradle's own benchmarks on a 5,000+ module monorepo show sync time dropping from 5m09s to 2m44s.
The feature is distinct from `org.gradle.parallel=true`, which parallelizes task execution, not project configuration.
Projects with custom scripts or third-party plugins that perform cross-project access will fail to configure with Isolated Projects enabled.
Conclusions

The collaboration between Gradle, Google, and JetBrains on this feature shows that the Android build toolchain's concurrency problems are finally being treated as a shared infrastructure concern, not just a plugin or IDE issue.

While the speedup is dramatic for monorepos, the author notes that for developers in China, network latency to remote repositories is often the dominant sync bottleneck, making this optimization less impactful in practice.

Upgrading to Gradle 9.7.0 is described as requiring 'courage,' hinting that the broader ecosystem of Android Gradle plugins is not yet fully compatible with the new isolation rules.

Concepts & terms
Isolated Projects
A Gradle feature that enforces a concurrency contract where each project's configuration logic can only access its own mutable state, enabling safe parallel configuration across all modules in a build.
Configuration Cache
A Gradle optimization that skips the entire configuration phase on subsequent builds if no configuration inputs have changed, storing the result for reuse.
Configuration Phase
The stage in a Gradle build where build scripts are evaluated, plugins are applied, and tasks are registered, before any compilation or packaging executes.
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