If the nested type is a managed type (Gradle can generate its implementation), you can define a nested property with:
```
interface NestedType {
    Property<String> getSomeProperty()
}
class Example {
    @Nested
    NestedType getNestedProperty()
}
```
Otherwise, if the nested type requires an implementation class, you'll need to manage the lifecycle of it:
```
interface NestedType {

          .build();

  /**
   * type → implementation. Inherently mutable interfaces and abstract classes are mapped to their
   * default implementations and are "new"d upon get().
   */
  private static final ConcurrentMap<Class<?>, Class<?>> implementations = Maps.newConcurrentMap();

  private static <T> void setImplementation(Class<T> type, Class<? extends T> implementation) {

 * this case, you should override {@code add(Object)} as well, either providing your own
 * implementation, or delegating to the provided {@code standardAdd} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingMultiset}.
 *

 * override {@code putAll} as well, either providing your own implementation, or delegating to the
 * provided {@code standardPutAll} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingNavigableMap}.
 *

 * override {@code putAll} as well, either providing your own implementation, or delegating to the
 * provided {@code standardPutAll} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingNavigableMap}.
 *

 * override {@code putAll} as well, either providing your own implementation, or delegating to the
 * provided {@code standardPutAll} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingMap}.
 *

 * this case, you should override {@code add(Object)} as well, either providing your own
 * implementation, or delegating to the provided {@code standardAdd} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingMultiset}.
 *

        implementation(projects.okhttpUrlconnection)
        implementation(projects.mockwebserver3)
        implementation(projects.mockwebserver3Junit4)
        implementation(projects.mockwebserver3Junit5)
        implementation(projects.mockwebserver)
        implementation(projects.loggingInterceptor)
        implementation(projects.okhttpBrotli)
        implementation(projects.okhttpDnsoverhttps)

     *
     * @param parser The XML parser
     * @return Name of the custom implementation; otherwise {@code null}
     */
    private static String parseImplementation(final XmlPullParser parser) {
        return parser.getAttributeValue(null, "implementation");
    }

    /**
     * Attempts to load the named implementation, uses default implementation if no name is given.

 * override {@code putAll} as well, either providing your own implementation, or delegating to the
 * provided {@code standardPutAll} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingMap}.
 *