tasks.register("show") {
    def property = objects.property(String)

    // Set a convention
    property.convention("convention 1")

    println("value = " + property.get())

    // Can replace the convention
    property.convention("convention 2")
    println("value = " + property.get())

    property.set("explicit value")

    // Once a value is set, the convention is ignored
    property.convention("ignored convention")

tasks.register("show") {
    val property = objects.property(String::class)

    // Set a convention
    property.convention("convention 1")

    println("value = " + property.get())

    // Can replace the convention
    property.convention("convention 2")
    println("value = " + property.get())

    property.set("explicit value")

    // Once a value is set, the convention is ignored
    property.convention("ignored convention")

    get() = extensions.extraProperties


/**
 * Provides property delegate for typed access to extra properties.
 */
operator fun ExtraPropertiesExtension.provideDelegate(receiver: Any?, property: KProperty<*>): MutablePropertyDelegate =
    if (property.returnType.isMarkedNullable) NullableExtraPropertyDelegate(this, property.name)
    else NonNullExtraPropertyDelegate(this, property.name)


private
class NonNullExtraPropertyDelegate(

        property.set("12")
        return property
    }

    Property<String> propertyWithCompletedProducer() {
        def task = Mock(Task)
        def state = Mock(TaskState)
        _ * task.toString() >> "<task>"
        _ * task.state >> state
        _ * state.executed >> true
        def owner = Stub(ModelObject)
        _ * owner.taskThatOwnsThisObject >> task

        "System.properties['some.property']"                   | _
        "System.getProperties().get('some.property')"          | _
        "getProperties().get('some.property')"                 | _
        "System.getProperty('some.property')"                  | _
        "getProperty('some.property')"                         | _
        "System.getProperty('some.property', 'default.value')" | _
        "getProperty('some.property', 'default.value')"        | _

import org.gradle.api.provider.MapProperty;
import org.gradle.api.provider.Property;

public interface CheckstyleActionParameters extends AntWorkParameters {
    RegularFileProperty getConfig();

    ConfigurableFileCollection getSource();

    Property<Integer> getMaxErrors();

    Property<Integer> getMaxWarnings();

    Property<Boolean> getIgnoreFailures();

    DirectoryProperty getConfigDirectory();

        "System.getProperties().get(\"some.property\")"            | _
        "System.getProperty(\"some.property\")"                    | _
        "System.getProperty(\"some.property\", \"default.value\")" | _
        "System.setProperty(\"some.property\", \"new.value\")"     | _
        "System.clearProperty(\"some.property\")"                  | _
    }

    def "setProperties is instrumented in Java"() {

    /**
     * Adds an element to the property value.
     *
     * <p>The given provider will be queried when the value of this property is queried.
     *
     * <p>
     * When invoked on a property with no value, this method first sets the value
     * of the property to its current convention value, if set, or an empty collection.
     * </p>
     * <p>Even if the given provider has no value, after this method is invoked,

        groupId = objectFactory.property(String.class);
        artifactId = objectFactory.property(String.class);
        version = objectFactory.property(String.class);
        message = objectFactory.property(String.class);
    }

    @Override
    public Property<String> getGroupId() {
        return groupId;
    }

    @Override
    public Property<String> getArtifactId() {
        return artifactId;

        connection = objectFactory.property(String.class);
        developerConnection = objectFactory.property(String.class);
        url = objectFactory.property(String.class);
        tag = objectFactory.property(String.class);
    }

    @Override
    public Property<String> getConnection() {
        return connection;
    }

    @Override
    public Property<String> getDeveloperConnection() {