project
- nice little sample projects that could be run in the core as well as integration tests

All Possible Errors
- invalid lifecycle phase (maybe same as bad CLI param, though you were talking about embedder too)
- <module> specified is not found
- malformed settings
- malformed POM
- local repository not writable
- remote repositories not available
- artifact metadata missing

   * values are merged using the specified merging function. If the merging function returns {@code
   * null}, then the collector removes the value that has been computed for the key thus far (though
   * future occurrences of the key would reinsert it).
   *
   * <p>Entries will appear in the encounter order of the first occurrence of the key.
   *
   * @since 21.0
   */

     * The returned list of versions is only dependent on the configured repositories and their contents.
     * The supplied request may also refer to a single concrete version rather than a version range.
     * In this case though, the result contains simply the (parsed) input version, regardless of the
     * repositories and their contents.
     *
     * @param artifact the artifact for which to resolve the versions

   *     neither fast nor secure. As of January 2017, we suggest:
   *     <ul>
   *       <li>For security:
   *           {@link Hashing#sha256} or a higher-level API.
   *       <li>For speed: {@link Hashing#goodFastHash}, though see its docs for caveats.
   *     </ul>
   */
  @Deprecated
  public static HashFunction md5() {
    return Md5Holder.MD5;
  }

  private static final class Md5Holder {

            largeArray[i] = "test" + i;
        }

        long memory2 = MemoryUtil.getUsedMemory();
        assertTrue(memory2 >= 0);
        // Memory usage should have changed (though we can't guarantee direction due to GC)
    }

    @Test
    public void test_integrationScenarios() {
        // Test realistic scenarios combining multiple methods

   * assume that using setCount() to increase the count is permitted iff add()
   * is permitted and similarly for decrease/remove(). We assume that a
   * setCount() no-op is permitted if either add() or remove() is permitted,
   * though we also allow it to "succeed" if neither is permitted.
   */

  private void assertSetCount(E element, int count) {
    setCountCheckReturnValue(element, count);

    assertEquals(

  // TODO(user): predecessors and successors should be collocated (reducing cache misses).
  // Might also explore collocating all of [hash, next, predecessor, successor] fields of an
  // entry in a *single* long[], though that reduces the maximum size of the set by a factor of 2

  /**
   * Pointer to the predecessor of an entry in insertion order. ENDPOINT indicates a node is the

  // TODO(user): predecessors and successors should be collocated (reducing cache misses).
  // Might also explore collocating all of [hash, next, predecessor, successor] fields of an
  // entry in a *single* long[], though that reduces the maximum size of the set by a factor of 2

  /**
   * Pointer to the predecessor of an entry in insertion order. ENDPOINT indicates a node is the

   * LinkedHashMap because one target node may be mapped to both a predecessor and a successor. A
   * LinkedHashMap combines two such edges into a single node-value pair, even though the edges may
   * not have been inserted consecutively.
   */
  private final @Nullable List<NodeConnection<N>> orderedNodeConnections;

  private int predecessorCount;
  private int successorCount;

    ReentrantLock lockD = otherFactory.newReentrantLock("LockD");

    // lockA -> lockD
    lockA.lock();
    lockD.lock();
    lockA.unlock();
    lockD.unlock();

    // lockD -> lockA should fail even though lockD is from a different factory.
    lockD.lock();
    PotentialDeadlockException expected =
        assertThrows(PotentialDeadlockException.class, () -> lockA.lock());