* Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)

     *
     * @return The list of exceptions that occurred during resolution, never {@code null}
     */
    @Nonnull
    List<Exception> getExceptions();

    /**
     * Gets the versions (in ascending order) that matched the requested range.
     *
     * @return The list of matching versions, never {@code null}. An empty list indicates
     *         no versions matched the requested range.
     */

     *
     * @return The identifier of the model from which the problem originated or an empty string if unknown, never
     *         {@code null}.
     */
    @Nonnull
    String getModelId();

    /**
     * Gets the applicable maven version/validation level of this problem
     * @return The version, never {@code null}.
     */
    @Nonnull
    Version getVersion();

    /**
     * Gets the identifier of this repository.
     *
     * @return the (case-sensitive) identifier, never {@code null}
     */
    @Nonnull
    String getId();

    /**
     * Gets the type of the repository, for example "default".
     *
     * @return the (case-sensitive) type of the repository, never {@code null}
     */
    @Nonnull
    String getType();

    /**
     * Creates artifact coordinates.
     *
     * @param request the request holding coordinates creation parameters
     * @return an {@code ArtifactCoordinates}, never {@code null}
     * @throws IllegalArgumentException if {@code request} is null or {@code request.session} is null or invalid
     */
    @Nonnull
    ArtifactCoordinates create(@Nonnull ArtifactCoordinatesFactoryRequest request);

  }

  /**
   * Inserts the specified element into this priority queue. As the queue is unbounded this method
   * will never block.
   *
   * @param e the element to add
   * @param timeout This parameter is ignored as the method never blocks
   * @param unit This parameter is ignored as the method never blocks
   * @return {@code true}
   * @throws ClassCastException if the specified element cannot be compared with elements currently

 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)

     * @param type The type of toolchain (e.g., "jdk", "compiler")
     * @param requirements Key-value pairs specifying toolchain requirements (e.g., "version": "11")
     * @return List of matching toolchains, never null
     * @throws ToolchainManagerException if toolchain retrieval fails
     */
    @Nonnull
    List<Toolchain> getToolchains(@Nonnull Session session, String type, Map<String, String> requirements);

    /**

 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)

 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)