// Then: Remove should throw UnsupportedOperationException
        UnsupportedOperationException exception = assertThrows(UnsupportedOperationException.class, iterator::remove);
        assertEquals("remove", exception.getMessage());
    }

    @Test
    @DisplayName("Close should be idempotent")
    void testClose_Idempotent() throws Exception {
        // Given: A valid iterator setup

        itr.next();
        assertThat(itr.hasNext(), is(not(true)));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testRemove() throws Exception {
        exception.expect(ClUnsupportedOperationException.class);
        exception.expectMessage(is("remove"));
        final ArrayIterator<String> itr = new ArrayIterator<String>("1", "2");
        itr.remove();
    }

 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.fess.exception;

/**
 * System exception class for the Fess search engine.
 * This exception is thrown when system-level errors occur in the Fess application,
 * such as configuration errors, initialization failures, or critical runtime issues.
 */

        try {
            dataIndexHelper.crawl("test-session");
            assertTrue("Should complete quickly with empty config list", true);
        } catch (Exception e) {
            assertTrue("Exception handling should be fast", true);
        }
    }

    public void test_crawl_withConfigIdList_emptyList() {
        try {
            List<String> configIds = Arrays.asList("id1", "id2");

        assertNotNull(exception);
        assertNull(exception.getMessage());
        assertNull(exception.getCause());
    }

    public void test_constructor_withNullCause() {
        // Test with null cause
        DataStoreException exception = new DataStoreException((Throwable) null);

        assertNotNull(exception);
        assertNull(exception.getCause());
        assertNull(exception.getMessage());
    }

 *       will be thrown.
 *   <li>If no exceptions or errors were thrown in the try block, the <i>first</i> exception thrown
 *       by an attempt to close a resource will be thrown.
 *   <li>Any exception caught when attempting to close a resource that is <i>not</i> thrown (because
 *       another exception is already being thrown) is <i>suppressed</i>.
 * </ul>
 *

 * includes both natural exceptions such as unreachable servers, as well as synthetic exceptions
 * when responses are of an unexpected type or cannot be decoded.
 *
 * Other exception types cancel the current call:
 *
 *  * For synchronous calls made with [Call.execute], the exception is propagated to the caller.
 *

  final Collection<? extends Throwable> exceptions;

  private ClusterException(Collection<? extends Throwable> exceptions) {
    super(
        exceptions.size() + " exceptions were thrown. The first exception is listed as a cause.",
        exceptions.iterator().next());
    ArrayList<? extends Throwable> temp = new ArrayList<>(exceptions);
    this.exceptions = Collections.unmodifiableCollection(temp);
  }

                throw new RuntimeException("Test exception in listener");
            }
        });

        try {
            factory.destroyObject(pooledObject);
            fail("Should propagate exception from listener");
        } catch (Exception e) {
            assertTrue(e.getMessage().contains("Test exception"));
        }
    }

    /**

{* ../../docs_src/handling_errors/tutorial002.py hl[14] *}

## Install custom exception handlers { #install-custom-exception-handlers }

You can add custom exception handlers with <a href="https://www.starlette.io/exceptions/" class="external-link" target="_blank">the same exception utilities from Starlette</a>.

Let's say you have a custom exception `UnicornException` that you (or a library you use) might `raise`.