# Handling Errors { #handling-errors }

There are many situations in which you need to notify an error to a client that is using your API.

This client could be a browser with a frontend, a code from someone else, an IoT device, etc.

You could need to tell the client that:

* The client doesn't have enough privileges for that operation.
* The client doesn't have access to that resource.
* The item the client was trying to access doesn't exist.
* etc.

    public void test_execute_noMaxProcessLimit() {
        // Setup test
        crawlJob = new CrawlJob() {
            @Override
            protected int getRunningJobCount() {
                return 100; // Many processes
            }

            @Override
            protected void executeCrawler() {
                // Mock execution
            }
        };

                + expected
                + ", actual = "
                + actual);
      }
    }

    if (expectedIter.hasNext() || actualIter.hasNext()) {
      // actual either had too few or too many elements
      fail(
          "contents were not equal and in the same order: "
              + "expected = "
              + expected
              + ", actual = "
              + actual);
    }
  }

import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**
 * A {@link Table} whose contents will never change, with many other important properties detailed
 * at {@link ImmutableCollection}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *

        fileNameField.setAccessible(true);
        assertEquals("", fileNameField.get(emptyNameRequest));

        // Test with long fileName
        String longFileName = "very-long-file-name-with-many-characters-that-could-potentially-cause-issues.txt";
        Smb2CloseRequest longNameRequest = new Smb2CloseRequest(mockConfig, testFileId, longFileName);
        assertEquals(longFileName, fileNameField.get(longNameRequest));

/**
 * Dispatches events to listeners, and provides ways for listeners to register themselves.
 *
 * <h2>Avoid EventBus</h2>
 *
 * <p><b>We recommend against using EventBus.</b> It was designed many years ago, and newer
 * libraries offer better ways to decouple components and react to events.
 *
 * <p>To decouple components, we recommend a dependency-injection framework. For Android code, most

 *
 * A URL has several components.
 *
 * ### Scheme
 *
 * Sometimes referred to as *protocol*, A URL's scheme describes what mechanism should be used to
 * retrieve the resource. Although URLs have many schemes (`mailto`, `file`, `ftp`), this class only
 * supports `http` and `https`. Use [java.net.URI][URI] for URLs with arbitrary schemes.
 *
 * ### Username and Password
 *

import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**
 * A {@link RangeMap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * @author Louis Wasserman
 * @since 14.0
 */
@GwtIncompatible // NavigableMap

            assertTrue(rateLimiter.checkAttempt("user2", "192.168.1." + i));
        }
    }

    @Test
    public void testGlobalRateLimit() throws Exception {
        // Make many attempts to trigger global rate limit
        for (int i = 1; i <= 20; i++) {
            assertTrue(rateLimiter.checkAttempt("user" + i, "192.168.1." + i), "Attempt " + i + " should be allowed");
        }

    } catch (IndexOutOfBoundsException expected) {
    } catch (IllegalArgumentException expected) {
      /*
       * The subList() docs claim that this should be an
       * IndexOutOfBoundsException, but many JDK implementations throw
       * IllegalArgumentException:
       * https://bugs.openjdk.org/browse/JDK-4506427
       */
    }
  }