/**
 * The annotated element can be {@code null}.
 *
 * @see Nonnull
 * @since 4.0.0
 */
@Experimental
@Documented
@Retention(RetentionPolicy.CLASS)

     */
    @Nonnull
    Optional<Source> getUserToolchainsSource();

    @Nonnull
    static ToolchainsBuilderRequest build(
            @Nonnull Session session, @Nullable Source globalToolchainsSource, @Nullable Source userToolchainsSource) {
        return builder()
                .session(nonNull(session, "session cannot be null"))
                .globalToolchainsSource(globalToolchainsSource)

         * found at the given file or in the given directory.
         *
         * @since 4.0.0
         */
        @Nullable
        Path locateExistingPom(@Nonnull Path project);
    }

    @Nullable
    ModelSource resolve(@Nonnull ModelLocator modelLocator, @Nonnull String relative);

    @Nonnull
    static ModelSource fromPath(@Nonnull Path path) {

     */
    <T> boolean replace(@Nonnull Key<T> key, @Nullable T oldValue, @Nullable T newValue);

    /**
     * Gets the session data associated with the specified key.
     *
     * @param key the key for which to retrieve the session data, must not be {@code null}
     * @return the session data associated with the key or {@code null} if none
     */
    @Nullable
    <T> T get(@Nonnull Key<T> key);

    /**

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

/**
 * An XML writer request.
 *
 * @since 4.0.0
 * @param <T> the object type to read
 */
@Experimental
public interface XmlWriterRequest<T> {

    @Nullable
    Path getPath();

    @Nullable
    OutputStream getOutputStream();

    @Nullable
    Writer getWriter();

    @Nonnull
    T getContent();

                return new Exclusion() {
                    @Nullable
                    @Override
                    public String getGroupId() {
                        return exclusion.getGroupId();
                    }

                    @Nullable
                    @Override
                    public String getArtifactId() {

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

/**
 * Describes a problem that was encountered during project building. A problem can either be an exception that was
 * thrown or a simple string message. In addition, a problem carries a hint about its source.
 *

 * <p>
 * Annotated fields must not be null after construction has completed.
 * <p>
 * When this annotation is applied to a method it applies to the method return value.
 *
 * @see Nullable
 * @since 4.0.0
 */
@Experimental
@Documented
@Retention(RetentionPolicy.CLASS)
@Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD})

"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

  patches should only highlight the actual difference, not being disturbed by any formatting issues:
  + Only use spaces for indentation.
  + Create minimal diffs - disable on save actions like reformat source code or organize imports.
    If you feel the source code should be reformatted, create a separate PR for this change.
  + Check for unnecessary whitespace with `git diff --check` before committing.