for (Plugin element : tgt) {
                    Object key = getPluginKey().apply(element);
                    Plugin existing = master.get(key);
                    if (existing != null) {
                        element = mergePlugin(element, existing, sourceDominant, context);

                        master.put(key, element);

                        if (!pending.isEmpty()) {

 * because of the possibility of splitting a surrogate pair. The only case in which it is safe to
 * escape strings and concatenate the results is if you can rule out this possibility, either by
 * splitting an existing long string into short strings adaptively around {@linkplain
 * Character#isHighSurrogate surrogate} {@linkplain Character#isLowSurrogate pairs}, or by starting
 * with short strings already known to be free of unpaired surrogates.

 *
 */
public interface MavenExecutionRequestPopulator {
    /**
     * Copies the values from the given toolchains into the specified execution request. This method will replace any
     * existing values in the execution request that are controlled by the toolchains. Hence, it is expected that this
     * method is called on a new/empty execution request before the caller mutates it to fit its needs.
     *

            for (PluginExecution element : tgt) {
                Object key = getPluginExecutionKey().apply(element);
                PluginExecution existing = merged.get(key);
                if (existing != null) {
                    element = mergePluginExecution(element, existing, sourceDominant, context);
                }
                merged.put(key, element);
            }

            builder.executions(merged.values());

            Files.deleteIfExists(target);
            result = "";
        } else {
            String current = sha1(src);
            String existing = sourceState.get();
            if (!Objects.equals(current, existing)) {
                defaultConsumerPomArtifactTransformer.transform(project, session, src, target);
                Files.setLastModifiedTime(target, Files.getLastModifiedTime(src));

                    e.printStackTrace();
                }
                throw new DIException("No binding to construct an instance for key "
                        + key.getDisplayString() + ".  Existing bindings:\n"
                        + getBoundKeys().stream()
                                .map(Key::toString)
                                .map(String::trim)
                                .sorted()

 *     constructed based on an existing {@code Network} using {@link #from(Network)}.
 * @param <E> The most general edge type this builder will support. This is normally {@code Object}
 *     unless it is constrained by using a method like {@link #edgeOrder}, or the builder is
 *     constructed based on an existing {@code Network} using {@link #from(Network)}.
 * @since 20.0
 */
@Beta

    // next map.get()
    when(backingMap.get(KEY)).thenReturn(existingZero);
    // since get returned zero, try a replace; that fails due to a simulated race
    when(backingMap.replace(eq(KEY), eq(existingZero), isA(AtomicInteger.class))).thenReturn(false);
    when(backingMap.putIfAbsent(eq(KEY), isA(AtomicInteger.class))).thenReturn(existing);

    // another map.get()

/**
 * Implementation of {@link Multimap} using hash tables.
 *
 * <p>The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an
 * existing key-value pair has no effect.
 *
 * <p>Keys and values may be null. All optional multimap methods are supported, and all returned
 * views are modifiable.
 *

      } // else no check necessary, all index values are valid
      L existing = locks.get(index);
      if (existing != null) {
        return existing;
      }
      L created = supplier.get();
      existing = locks.putIfAbsent(index, created);
      return MoreObjects.firstNonNull(existing, created);
    }

    @Override
    public int size() {
      return size;
    }
  }