// Even though the contract in System.getProperties() specifies that a value will exist for
      // all of the listed keys, for some reason the "java.compiler" key returns null in some JVMs.
      if (property == JAVA_COMPILER) {
        continue;
      }
      // Removed in Java 9:
      // https://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG-GUID-2C896CA8-927C-4381-A737-B1D81D964B7B

Each process, or "runtime", applies different constraints to the code that runs in that process.
For example, each process has different supported JVMs and a different set of services available for dependency injection.
While a lot of Gradle source code runs only in the Gradle daemon, not all of it does so.