A central part of the Gradle architecture is the "build state model", which holds the state for each piece and coordinates state transitions and other mutations. 
Most source code in Gradle is arranged by which part(s) of the build state model it acts on.
This affects the lifecycle of the code and the set of services available for dependency injection.

/**
 * A generic JUnit test which tests {@code stream} operations on a collection. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

    segment = cache.segments[0];
    chain = null;
    for (int i = 0; i < length; i++) {
      Object key = new Object();
      // TODO(b/145386688): This access should be guarded by 'this.segment', which is not currently
      // held
      chain = segment.newEntry(key, cache.hash(key), chain);
      if (i == 0) {
        head = chain;
      }
    }
  }

  @SuppressWarnings("GuardedBy")
  @Benchmark

 * states it cannot ever leave them.
 *
 * <p>Implementors of this interface are strongly encouraged to extend one of the abstract classes
 * in this package which implement this interface and make the threading and state management
 * easier.
 *
 * @author Jesse Wilson
 * @author Luke Sandberg
 * @since 9.0 (in 1.0 as {@code com.google.common.base.Service})
 */

import org.junit.Ignore;

/**
 * A generic JUnit test which tests multiset-specific serialization. Can't be invoked directly;
 * please see {@link MultisetTestSuiteBuilder}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible // but no-op
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

import org.junit.Ignore;

/**
 * A generic JUnit test which tests multiset-specific serialization. Can't be invoked directly;
 * please see {@link MultisetTestSuiteBuilder}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible // but no-op
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

/**
 * A generic JUnit test which tests {@code addAll(Collection)} operations on a list. Can't be
 * invoked directly; please see {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@link List#replaceAll}. Can't be invoked directly; please see
 * {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

          <defaultValue>true</defaultValue>
        </field>
        <field>
          <name>requiredJavaVersion</name>
          <version>1.1.0+</version>
          <description>
            A version range which specifies the supported Java versions. A version range can either use the usual mathematical syntax "[2.0.10,2.1.0),[3.0,)" or use a single version "2.2.1". The latter is a short form for "[2.2.1,)", i.e. denotes the minimum version required.

        </field>
        <field>
          <name>activeProfiles</name>
          <version>1.0.0</version>
          <description><![CDATA[
            List of manually-activated build profiles, specified in the order in which
            they should be applied.
          ]]></description>
          <association>
            <type>String</type>
            <multiplicity>*</multiplicity>
          </association>
        </field>