Gradle tracks the state of each piece and transitions each piece through its lifecycle as the build runs.

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.

     * For example, resolves "1.0-SNAPSHOT" to "1.0-20090208.132618-23".
     *
     * @param session The repository session, must not be {@code null}.
     * @param artifactCoordinates The artifact coordinates for which the version needs to be resolved, must not be {@code null}
     * @return The version result, never {@code null}.
     * @throws VersionResolverException If the metaversion could not be resolved.
     */
    @Nonnull

    }

    /**
     * Gets the identifier of the POM whose effective model could not be built. The general format of the identifier is
     * {@code <groupId>:<artifactId>:<version>} but some of these coordinates may still be unknown at the point the
     * exception is thrown so this information is merely meant to assist the user.
     *
     * @return The identifier of the POM or an empty string if not known, never {@code null}.

        return result;
    }

    /**
     * Gets the identifier of the POM whose effective model could not be built. The general format of the identifier is
     * {@code <groupId>:<artifactId>:<version>} but some of these coordinates may still be unknown at the point the
     * exception is thrown so this information is merely meant to assist the user.
     *
     * @return The identifier of the POM or an empty string if not known, never {@code null}.

     * @return {@code true} if the artifact is a snapshot, {@code false} otherwise
     * @see org.apache.maven.api.Session#isVersionSnapshot(String)
     */
    boolean isSnapshot();

    /**
     * {@return coordinates with the same identifiers as this artifact}
     * This is a shortcut for {@code session.createArtifactCoordinates(artifact)}.
     *
     * @see org.apache.maven.api.Session#createArtifactCoordinates(Artifact)
     */

            version = "[unknown-version]";
        }

        return toId(groupId, artifactId, version);
    }

    /**
     * Creates a user-friendly artifact id from the specified coordinates.
     *
     * @param groupId The group id, may be {@code null}.
     * @param artifactId The artifact id, may be {@code null}.
     * @param version The version, may be {@code null}.

  @Test fun onlyOneCoordinatorWaitingToStartFutureTasks() {
    // Enqueueing the red task starts a coordinator thread.
    redQueue.execute("red task", 100.µs) {
      log += "red:run@${taskFaker.nanoTime}"
    }
    assertThat(taskFaker.executeCallCount).isEqualTo(1)

    // Enqueueing the blue task doesn't need a 2nd coordinator yet.
    blueQueue.execute("blue task", 200.µs) {
      log += "blue:run@${taskFaker.nanoTime}"
    }

/**
 * Artifact Metadata that is resolved independent of Artifact itself.
 *
 */
@Deprecated
public class ArtifactMetadata {
    /**
     * standard glorified artifact coordinates
     */
    protected String groupId;

    protected String artifactId;
    protected String version;
    protected String type;
    protected ArtifactScopeEnum artifactScope;
    protected String classifier;

                                                + " JAR (about to be installed/deployed) contains Maven Plugin metadata for"
                                                + " conflicting coordinates: {}:{}."
                                                + " Your JAR contains rogue Maven Plugin metadata."

          return readyTask
        }

        // Notify the coordinator of a task that's coming up soon.
        coordinatorWaiting -> {
          if (minDelayNanos < coordinatorWakeUpAt - now) {
            backend.coordinatorNotify(this@TaskRunner)
          }
          return null
        }

        // No other thread is coordinating. Become the coordinator!
        else -> {
          coordinatorWaiting = true