The <<plugins#sec:subprojects_plugins_dsl,Using Gradle plugins>> chapter explains how you can declare plugins in the root project build script with a version and then apply them to the appropriate subprojects' build scripts. What follows is an example of this approach using three subprojects and three plugins. Note how the root build script only declares the community plugins as the Java Library Plugin is tied to the version of Gradle you are using:

[[ex:multi_project_ratpack]]

Build logic like the above example creates challenges in resolving declared dependencies, as reporting tools will display this dependency as if the user declared the version as "2.0", even though they never did.
Instead, the build logic can avoid iteration and mutation by declaring a `preferred` version constraint on the dependency's coordinates.
This allows the dependency management engine to use the version declared on the constraint if no other version is declared.

The Property instances need to be declared as inputs or outputs in the usual ways, such as attaching annotations such as `@OutputFile` or using the runtime API to register the property.

For example, you could previously use the following syntax and have both outputFile instances registered as declared outputs:

====
[.multi-language-sample]
=====
.build.gradle
[source,groovy]

        assertResolvedPomDependencyManagement(key, 'version-two')
        pomReader.findDependencyDefaults(key) == pomReader.dependencyMgt[key]
    }

    def "finds dependency default if declared in active profile"() {
        when:
        pomFile << """
<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>group-one</groupId>
    <artifactId>artifact-one</artifactId>

        metadata.moduleVersionId.group == 'test'
        metadata.moduleVersionId.name == 'child_2.12'
        metadata.moduleVersionId.version == '1.0.0'

    }

    def "merges dependencies declared in pom with those declared in parent"() {
        given:
        def parent = tmpDir.file("parent.xlm") << """
<project>
    <modelVersion>4.0.0</modelVersion>
    <groupId>group-one</groupId>

//   GTEST_AMBIGUOUS_ELSE_BLOCKER_ - for disabling a gcc warning.
//   GTEST_ATTRIBUTE_UNUSED_  - declares that a class' instances or a
//                              variable don't have to be used.
//   GTEST_DISALLOW_ASSIGN_   - disables operator=.
//   GTEST_DISALLOW_COPY_AND_ASSIGN_ - disables copy ctor and operator=.
//   GTEST_MUST_USE_RESULT_   - declares that a function's result must be used.
//
// Synchronization:

                conf 'org.apache.groovy:json:2.5'
                conf 'org.springframework:core:1.0'
            }
        """

        and:
        'a rule which declares that Groovy belongs to the Groovy and the Spring platforms'()

        when:
        expectAlignment {
            module('core') {
                group('org.apache.groovy') tries('2.4') alignsTo('2.5')

//   GTEST_AMBIGUOUS_ELSE_BLOCKER_ - for disabling a gcc warning.
//   GTEST_ATTRIBUTE_UNUSED_  - declares that a class' instances or a
//                              variable don't have to be used.
//   GTEST_DISALLOW_ASSIGN_   - disables operator=.
//   GTEST_DISALLOW_COPY_AND_ASSIGN_ - disables copy ctor and operator=.
//   GTEST_MUST_USE_RESULT_   - declares that a function's result must be used.
//
// Synchronization:

  private static WildcardType canonicalizeWildcardType(
      TypeVariable<?> declaration, WildcardType type) {
    Type[] declared = declaration.getBounds();
    List<Type> upperBounds = new ArrayList<>();
    for (Type bound : type.getUpperBounds()) {
      if (!any(declared).isSubtypeOf(bound)) {
        upperBounds.add(canonicalizeWildcardsInType(bound));
      }
    }

  private static WildcardType canonicalizeWildcardType(
      TypeVariable<?> declaration, WildcardType type) {
    Type[] declared = declaration.getBounds();
    List<Type> upperBounds = new ArrayList<>();
    for (Type bound : type.getUpperBounds()) {
      if (!any(declared).isSubtypeOf(bound)) {
        upperBounds.add(canonicalizeWildcardsInType(bound));
      }
    }