assertTrue(endLatch.await(30, TimeUnit.SECONDS), "All threads should complete within timeout");
        executor.shutdown();

        // Then - Verify no exceptions occurred
        if (!exceptions.isEmpty()) {
            fail("Concurrent operations caused exceptions: " + exceptions.get(0));
        }

        assertEquals(threadCount * opsPerThread, successCount.get(), "All operations should succeed");
    }

    /**

        System.out.printf("  Avg tree operation time: %.2f ns%n", avgOpTimeNs);

        // Verify thread safety and performance
        assertTrue(exceptions.isEmpty(), "No exceptions should occur with thread-safe collections: " + exceptions);
        assertEquals(threadCount * operationsPerThread, treeOperations.get());
        assertTrue(avgOpTimeNs < 100000, "Tree operations should be reasonable with CopyOnWriteArrayList");

                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"));
        }
    }

    /**

                        BufferCache.releaseBuffer(buffer);
                        successCount.incrementAndGet();
                    }
                } catch (Exception e) {
                    synchronized (exceptions) {
                        exceptions.add(e);
                    }
                } finally {
                    endLatch.countDown();
                }
            });
        }

     * exception, and wrongly believes that its exception is new (leading it to logging it when it
     * shouldn't)
     *
     * Our solution is for threads to CAS seenExceptionsField from null to a Set populated with _the
     * initial exception_, no matter which thread does the work. This ensures that
     * seenExceptionsField always contains not just the current thread's exception but also the
     * initial thread's.
     */

```

### Exception Handling
```java
import org.codelibs.core.exception.*;

// Runtime exception wrappers eliminate try-catch boilerplate
try {
    // Code that might throw checked exceptions
    return ClassUtil.newInstance(className); // Wraps checked exceptions automatically
} catch (ClassNotFoundRuntimeException e) {
    // Handle the wrapped 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`.

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

    /**
     * Test constructor with various cause types
     */
    public void test_constructor_withVariousCauseTypes() {
        // With Exception cause
        Exception exceptionCause = new Exception("Exception cause");

Before FastAPI 0.110.0, if you used a dependency with `yield`, and then you captured an exception with `except` in that dependency, and you didn't raise the exception again, the exception would be automatically raised/forwarded to any exception handlers or the internal server error handler.

    PLATFORM {
      @GwtIncompatible
      @J2ktIncompatible
      @Override
      // returns the types available in "normal" environments
      ImmutableMap<Class<? extends Throwable>, Predicate<Throwable>> exceptions() {
        return ImmutableMap.of(
            InvocationTargetException.class,
            e -> e instanceof InvocationTargetException,
            StackOverflowError.class,