# Dependencies { #dependencies }

**FastAPI** has a very powerful but intuitive **<dfn title="also known as components, resources, providers, services, injectables">Dependency Injection</dfn>** system.

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection" { #what-is-dependency-injection }

                    + "INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES \\(INCLUDING, BUT\n"
                    + "NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,\n"
                    + "DATA, OR PROFITS; OR BUSINESS INTERRUPTION\\) HOWEVER CAUSED AND ON ANY\n"
                    + "THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT\n"

  - type: input
    id: OS
    attributes:
      label: OS platform and distribution
      placeholder: e.g., Linux Ubuntu 16.04
  - type: input
    id: Mobile
    attributes:
      label: Mobile device
      placeholder: e.g., Linux Ubuntu 16.04
  - type: input
    id: Python
    attributes:
      label: Python version
      placeholder: e.g., 3.9
  - type: input
    id: Bazel
    attributes:

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services;

import java.util.List;

import org.apache.maven.api.Service;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;

import java.util.Map;

import org.apache.maven.settings.Settings;

/**
 * Handles deserialization of settings from some kind of textual format like XML.
 *
 * @deprecated since 4.0.0, use {@link org.apache.maven.api.services.xml.SettingsXmlFactory} instead
 */
@Deprecated(since = "4.0.0")
public interface SettingsReader {

    /**

/**
 * Handles deserialization of toolchains from some kind of textual format like XML.
 *
 * @since 3.3.0
 * @deprecated since 4.0.0, use {@code org.apache.maven.api.services.xml.ToolchainsXmlFactory} instead
 */
@Deprecated(since = "4.0.0")
public interface ToolchainsReader {

    /**

[Andere Sponsoren](https://fastapi.tiangolo.com/de/fastapi-people/#sponsors)

## Meinungen { #opinions }

„_[...] Ich verwende **FastAPI** heutzutage sehr oft. [...] Ich habe tatsächlich vor, es für alle **ML-Services meines Teams bei Microsoft** zu verwenden. Einige davon werden in das Kernprodukt **Windows** und einige **Office**-Produkte integriert._“

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.api.services;

import org.apache.maven.api.Service;
import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**

 * thrown or a simple string message. In addition, a problem carries a hint about its source, e.g. the settings file
 * that exhibits the problem.
 *
 * @deprecated since 4.0.0, use {@link org.apache.maven.api.services.SettingsBuilder} instead
 */
@Deprecated(since = "4.0.0")
public class DefaultSettingsProblem implements SettingsProblem {

    private final String source;

    private final int lineNumber;

import org.apache.maven.model.merge.MavenModelMerger;
import org.codehaus.plexus.util.StringUtils;

/**
 * Handles normalization of a model.
 *
 * @deprecated use {@code org.apache.maven.api.services.ModelBuilder} instead
 */
@Named
@Singleton
@Deprecated(since = "4.0.0")
public class DefaultModelNormalizer implements ModelNormalizer {

    private DuplicateMerger merger = new DuplicateMerger();