/**
     * The different severity levels for a problem, in decreasing order.
     *
     * @since 4.0.0
     */
    @Experimental
    enum Severity {
        FATAL, //
        ERROR, //
        WARNING //
    }

 * should use the type safe {@link #putInstance}.
 *
 * <p>Also, if caller suppresses unchecked warnings and passes in an {@code Iterable<String>} for
 * type {@code Iterable<Integer>}, the map won't be able to detect and throw type error.
 *
 * <p>Like any other {@code Map<Class, Object>}, this map may contain entries for primitive types,
 * and a primitive type and its corresponding wrapper type may map to different values.
 *

        List<Toolchain> toolchains = toolchainManager.getToolchains(session, "unknown", null);

        assertEquals(0, toolchains.size());
        verify(logger).error("Missing toolchain factory for type: unknown. Possibly caused by misconfigured project.");
    }

    @Test
    void testModelAndFactory() {
        MavenSession session = mock(MavenSession.class);

        IOException ioEx = new IOException("Unable to establish loopback connection", connEx);
        MojoExecutionException mojoEx =
                new MojoExecutionException("Error executing Jetty: Unable to establish loopback connection", ioEx);

        ExceptionHandler exceptionHandler = new DefaultExceptionHandler();
        ExceptionSummary exceptionSummary = exceptionHandler.handleException(mojoEx);

         * the way 2.x works. When we're in strict mode, the removal of duplicates just saves other merging steps from
         * aftereffects and bogus error messages.
         */
        List<Dependency> dependencies = model.getDependencies();
        Map<String, Dependency> normalized = new LinkedHashMap<>(dependencies.size() * 2);

    class SneakyThrower<T extends Throwable> {
      @SuppressWarnings("unchecked") // intentionally unsafe for test
      void throwIt(Throwable t) throws T {
        throw (T) t;
      }
    }
    new SneakyThrower<Error>().throwIt(t);
  }

  private static class SomeCheckedException extends Exception {}

  private static class SomeUncheckedException extends RuntimeException {}

    class SneakyThrower<T extends Throwable> {
      @SuppressWarnings("unchecked") // intentionally unsafe for test
      void throwIt(Throwable t) throws T {
        throw (T) t;
      }
    }
    new SneakyThrower<Error>().throwIt(t);
  }

  private static class SomeCheckedException extends Exception {}

  private static class SomeUncheckedException extends RuntimeException {}

        }

        String version = context.getSystemProperties().get("java.version");

        if (version == null || version.isEmpty()) {
            problems.add(
                    BuilderProblem.Severity.ERROR,
                    ModelProblem.Version.BASE,
                    "Failed to determine Java version for profile " + profile.getId(),
                    activation.getLocation("jdk"));
            return false;
        }

    }
  }

  public void testNulls() {
    /*
     * Don't bother testing. All non-primitive parameters are used only to construct error messages.
     * We never want to pass null for them, so we haven't annotated them to say that null is
     * allowed. But at the same time, it seems wasteful to bother inserting the checkNotNull calls

      @SuppressWarnings("unchecked") // not really safe, but that's the point
      void throwIt(Throwable t) throws T {
        throw (T) t;
      }
    }
    new SneakyThrower<Error>().throwIt(t);
  }

  private static class SomeCheckedException extends Exception {}

  private static class SomeUncheckedException extends RuntimeException {}