return pb.start().waitFor();
        } catch (IOException e) {
            invokerRequest.logger().error("IO problem while executing command: " + cmdAndArguments, e);
            return 127;
        } catch (InterruptedException e) {
            invokerRequest.logger().error("Interrupted while executing command: " + cmdAndArguments, e);
            return 127;
        }
    }

      }
    },
    NO_SPLIT_TRY_ADVANCE {
      @Override
      <E extends @Nullable Object> void forEach(
          GeneralSpliterator<E> spliterator, Consumer<? super E> consumer) {
        while (spliterator.tryAdvance(consumer)) {
          // do nothing
        }
      }
    },
    MAXIMUM_SPLIT {
      @Override
      <E extends @Nullable Object> void forEach(

      }
    },
    NO_SPLIT_TRY_ADVANCE {
      @Override
      <E extends @Nullable Object> void forEach(
          GeneralSpliterator<E> spliterator, Consumer<? super E> consumer) {
        while (spliterator.tryAdvance(consumer)) {
          // do nothing
        }
      }
    },
    MAXIMUM_SPLIT {
      @Override
      <E extends @Nullable Object> void forEach(

 * general way.
 *
 * <p>A good example of usage of this class is for HTML escaping where the replacement array
 * contains information about the named HTML entities such as {@code &amp;} and {@code &quot;} while
 * {@link #escapeUnsafe} is overridden to handle general escaping of the form {@code &#NNNNN;}.
 *
 * <p>The size of the data structure used by {@link ArrayBasedUnicodeEscaper} is proportional to the

                        }
                        continue;
                    }
                }
                catch ( CIFSException e ) {
                    log.debug("Error while checking for reuse", e);
                    continue;
                }

                if ( log.isTraceEnabled() ) {
                    log.trace("Reusing transport connection " + conn);
                }

            new CheckedRunnable() {
              @Override
              @SuppressWarnings("ThreadPriorityCheck") // doing our best to test for races
              public void realRun() {
                while (!at.compareAndSet(2.0, 3.0)) {
                  Thread.yield();
                }
              }
            });

    assertTrue(at.compareAndSet(1.0, 2.0));
    awaitTermination(t);

            throw new PACDecodingException("Malformed kerberos ticket", e);
        }

        this.authorizations = new ArrayList<>();
        Enumeration<?> authElements = authSequence.getObjects();
        while ( authElements.hasMoreElements() ) {
            ASN1Sequence authElement = ASN1Util.as(ASN1Sequence.class, authElements);

   */
  protected final void notifyStarted() {
    monitor.enter();
    try {
      // We have to examine the internal state of the snapshot here to properly handle the stop
      // while starting case.
      if (snapshot.state != STARTING) {
        IllegalStateException failure =
            new IllegalStateException(
                "Cannot notifyStarted() when the service is " + snapshot.state);

          @Override
          @CheckForNull
          public E computeNext() {
            while (itr1.hasNext()) {
              E elem1 = itr1.next();
              if (!set2.contains(elem1)) {
                return elem1;
              }
            }
            while (itr2.hasNext()) {
              E elem2 = itr2.next();
              if (!set1.contains(elem2)) {

* Have shared logic (the same code logic again and again).
* Share database connections.
* Enforce security, authentication, role requirements, etc.
* And many other things...

All these, while minimizing code repetition.

## First Steps

Let's see a very simple example. It will be so simple that it is not very useful, for now.

But this way we can focus on how the **Dependency Injection** system works.