return (Class<? extends T>) implementations.get(type);
  }

  private static final Logger logger = Logger.getLogger(ArbitraryInstances.class.getName());

  /**
   * Returns an arbitrary instance for {@code type}, or {@code null} if no arbitrary instance can be
   * determined.
   */
  public static <T> @Nullable T get(Class<T> type) {
    T defaultValue = DEFAULTS.getInstance(type);
    if (defaultValue != null) {

    if (defaultValue != null) {
      return defaultValue;
    }
    @SuppressWarnings("unchecked") // All arbitrary instances are generics-safe
    T arbitrary = (T) ArbitraryInstances.get(type.getRawType());
    if (arbitrary != null) {
      return arbitrary;
    }
    if (type.getRawType() == Class.class) {
      // If parameter is Class<? extends Foo>, we return Foo.class

  /**
   * Returns a {@code Collector} that returns the {@code k} smallest (relative to the specified
   * {@code Comparator}) input elements, in ascending order, as an unmodifiable {@code List}. Ties
   * are broken arbitrarily.
   *
   * <p>For example:
   *
   * {@snippet :
   * Stream.of("foo", "quux", "banana", "elephant")
   *     .collect(least(2, comparingInt(String::length)))
   * // returns {"foo", "quux"}
   * }

        return ImmutableSet.of(getOnlyElement(set));
      default:
        return new ImmutableEnumSet<>(set);
    }
  }

  /*
   * Notes on EnumSet and <E extends Enum<E>>:
   *
   * This class isn't an arbitrary ForwardingImmutableSet because we need to
   * know that calling {@code clone()} during deserialization will return an
   * object that no one else has a reference to, allowing us to guarantee

    }

    /**
     * Test constructor DcerpcException(int error) with an unknown error code.
     */
    @Test
    void testConstructorWithError_unknownCode() {
        int errorCode = 0x12345678; // An arbitrary unknown error code
        DcerpcException exception = new DcerpcException(errorCode);

        assertEquals(errorCode, exception.getErrorCode(), "Error code should match the input.");

Apart from all the fancy words used here, the **Dependency Injection** system is quite simple.

Just functions that look the same as the *path operation functions*.

But still, it is very powerful, and allows you to declare arbitrarily deeply nested dependency "graphs" (trees).

/// tip

All this might not seem as useful with these simple examples.

But you will see how useful it is in the chapters about **security**.

        return Stream.of(Arguments.of(0, 0L, 0L, 0L, 0L), // all zeros
                Arguments.of(1, 1L, 1L, 1L, 1L), // ones
                Arguments.of(123, 456L, 789L, 101112L, 131415L), // arbitrary positives
                Arguments.of(Integer.MAX_VALUE, Long.MAX_VALUE, Long.MIN_VALUE, 999_999_999_999L, -1L), // extremes
                Arguments.of(-1, -2L, -3L, -4L, -5L) // negative values
        );
    }

    }

    @ParameterizedTest
    @CsvSource({ "0, 0", // all zeros
            "-1, 2147483647", // negative fid, max positive security
            "12345, 999" // arbitrary numbers
    })
    void toString_includesCorrectHexValues(int fid, int securityInformation) {
        NtTransQuerySecurityDesc cmd = new NtTransQuerySecurityDesc(fid, securityInformation);
        String result = cmd.toString();

import org.codehaus.plexus.interpolation.AbstractDelegatingValueSource;
import org.codehaus.plexus.interpolation.PrefixedValueSourceWrapper;
import org.codehaus.plexus.interpolation.QueryEnabledValueSource;

/**
 * Wraps an arbitrary object with an {@link ObjectBasedValueSource} instance, then
 * wraps that source with a {@link PrefixedValueSourceWrapper} instance, to which
 * this class delegates all of its calls.
 *

        // Prepare data
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        int defaultType = 99;
        writeLittleEndianInt(baos, defaultType);
        byte[] checksum = new byte[10]; // Arbitrary length
        for (int i = 0; i < checksum.length; i++) {
            checksum[i] = (byte) i;
        }
        baos.write(checksum);
        byte[] data = baos.toByteArray();

        // Create PacSignature