默认禁用Build Cache时Gradle Daemon的优势？兼解文档冲突疑问

First, let's clear up a key distinction that's easy to overlook: the Gradle Daemon's in-memory caching is completely separate from the persistent Build Cache feature. The docs you referenced aren't contradictory—they're describing two distinct caching layers, each serving different purposes.

1. What are the Gradle Daemon's advantages when Build Cache is disabled by default? #

Even without the disk-based Build Cache, the Daemon delivers significant performance gains that don't rely on persistent caching:

• Eliminates repeated JVM startup overhead: Unlike Maven, which spins up a brand-new JVM instance for every build, the Daemon is a long-lived process. This cuts out the time spent initializing the JVM, loading core Gradle classes, and warming up the runtime—this alone makes frequent, small builds feel much snappier.
• In-memory caching of build state: As noted in section 7.1, the Daemon stores your project's structure, resolved dependencies, task execution status, and even compiled classes in memory for its entire lifecycle. This means:
  • If you run gradle build twice back-to-back, the Daemon immediately knows which tasks are already up-to-date (no changes since the last run) and skips them entirely—no need to reparse the project or re-run unchanged tasks.
  • Resolved dependencies stay in memory, so you don't have to re-fetch or re-validate them on every build (unless you modify your build.gradle files).
• Stable runtime environment: The Daemon maintains a consistent JVM state, reducing variability in build times and avoiding issues from reinitializing classloaders over and over.

Note that the Windows-specific resource issue mentioned in section 7.5.5 is a potential risk (from poorly written build scripts that fail to release file handles), not a flaw in the Daemon itself—it's just that Windows is less forgiving of unclosed resources than Unix-like systems.

2. Is Gradle's performance comparable to mvn clean install -DskipTests when Build Cache is disabled? #

It depends on the scenario, but Gradle still holds an edge in most cases—even without the Build Cache:

• For incremental builds (no clean): Gradle's native incremental build logic (powered by the Daemon's in-memory state) is way faster than Maven's default behavior. Maven doesn't natively track task up-to-date status, so running mvn install -DskipTests twice will re-execute most tasks unless you use third-party plugins. Gradle, by contrast, skips all unchanged tasks automatically.
• For clean builds: Here the gap narrows, but Gradle still has advantages:
  • The Daemon's pre-warmed JVM avoids the JVM startup cost that Maven incurs every single time you run mvn clean install.
  • Gradle supports parallel task execution (enabled by default for multi-project builds), which speeds up execution by running independent tasks at the same time—something Maven doesn't do natively.
  • Gradle's dependency resolution engine is optimized to resolve dependencies more efficiently than Maven in many scenarios.

That said, if you're comparing a first-time clean build where all dependencies need to be fetched and all tasks executed, performance might be similar—but the Daemon will make subsequent builds drastically faster, whereas Maven will still take roughly the same time each run.

内容的提问来源于stack exchange，提问作者Mike3355