import org.gradle.api.internal.project.ProjectInternal;
import org.gradle.api.internal.project.ProjectRegistry;
import org.gradle.api.model.ObjectFactory;
import org.gradle.api.plugins.ExtensionContainer;
import org.gradle.api.problems.Problems;
import org.gradle.api.provider.Property;
import org.gradle.api.provider.ProviderFactory;
import org.gradle.initialization.DefaultProjectDescriptor;

}

class ExtensibleBeanWithInject implements ExtensionAware {
    @Override
    @Inject
    ExtensionContainer getExtensions() {
        throw new UnsupportedOperationException()
    }
}

class ExtensibleBeanWithCustomInject implements ExtensionAware {
    @Override
    @CustomInject
    ExtensionContainer getExtensions() {
        throw new UnsupportedOperationException()
    }
}

A link:{groovyDslPath}/org.gradle.api.Project.html[Project] has an associated link:{javadocPath}/org/gradle/api/plugins/ExtensionContainer.html[ExtensionContainer] object that contains all the settings and properties for the plugins that have been applied to the project.
You can provide configuration for your plugin by adding an extension object to this container.

 *
 * @deprecated Use extensions instead. This is scheduled for removal in Gradle 9.
 * @see org.gradle.api.plugins.ExtensionAware
 */
@Deprecated
public interface Convention extends ExtensionContainer {

    /**
     * Returns the plugin convention objects contained in this convention.
     *
     * @return The plugins. Returns an empty map when this convention does not contain any convention objects.

import org.gradle.api.internal.project.ProjectIdentifier;
import org.gradle.api.internal.tasks.TaskContainerInternal;
import org.gradle.api.internal.tasks.TaskDependencyUtil;
import org.gradle.api.plugins.ExtensionContainer;
import org.gradle.api.tasks.TaskContainer;
import org.gradle.internal.logging.text.TreeFormatter;
import org.gradle.internal.reflect.Instantiator;
import org.gradle.internal.service.ServiceRegistry;

import org.gradle.api.internal.project.ProjectInternal
import org.gradle.api.internal.project.ProjectRegistry
import org.gradle.api.invocation.Gradle
import org.gradle.api.invocation.GradleLifecycle
import org.gradle.api.plugins.ExtensionContainer
import org.gradle.api.plugins.ObjectConfigurationAction
import org.gradle.api.plugins.PluginContainer
import org.gradle.api.services.BuildServiceRegistry
import org.gradle.configuration.ConfigurationTargetIdentifier

import org.gradle.api.internal.artifacts.query.ArtifactResolutionQueryFactory
import org.gradle.api.internal.artifacts.type.ArtifactTypeRegistry
import org.gradle.api.internal.file.TestFiles
import org.gradle.api.plugins.ExtensionContainer
import org.gradle.api.reflect.TypeOf
import org.gradle.util.AttributeTestUtil
import org.gradle.util.TestUtil
import spock.lang.Specification

import java.util.concurrent.Callable

import org.gradle.api.invocation.Gradle
import org.gradle.api.logging.Logger
import org.gradle.api.logging.LoggingManager
import org.gradle.api.model.ObjectFactory
import org.gradle.api.plugins.ExtensionContainer
import org.gradle.api.plugins.ObjectConfigurationAction
import org.gradle.api.plugins.PluginContainer
import org.gradle.api.plugins.PluginManager
import org.gradle.api.provider.Provider

 *
 */
public interface ExtraPropertiesExtension {

    /**
     * The name of this extension in all {@link ExtensionContainer ExtensionContainers}, {@value}.
     */
    String EXTENSION_NAME = "ext";

    /**
     * Returns whether or not the extension has a property registered via the given name.
     *
     * <pre class='autoTested'>

                `register`(`name`, `type`.java, `configurationAction`)
            """,
            """
            inline fun <T : Any> org.gradle.api.plugins.ExtensionContainer.`create`(`name`: String, `type`: kotlin.reflect.KClass<T>, vararg `constructionArguments`: Any): T =
                `create`(`name`, `type`.java, *`constructionArguments`)
            """,
            """