Gradle项目java-demo示例mock无效（只有private有效）

Gradle项目运行java-demo示例，mock没有按照设置的期望运行，而是按照实际调用运行的。参考自助问题排查：发现在项目路径的build目录下找不到testable-agent.log（Gradle项目）文件，但是DemoPrivateAccessorTest以及DemoPrivateProcessorTest可以运行成功。

IDE:AndroidStudio4.1.3

Start with the java-demo Gradle project and compare its setup with DemoPrivateAccessorTest and DemoPrivateProcessorTest, which reportedly pass. Investigate why the expected mock behavior is not applied and why build/testable-agent.log is absent under build. Done means the demo honors configured expectations and produces the expected diagnostic log.

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