@Test
        @DisplayName("Should append referral data")
        void testAppend() {
            DfsReferralDataInternal toAppend = mock(DfsReferralDataInternal.class);

            // Test with mock
            doNothing().when(mockReferralData).append(toAppend);
            mockReferralData.append(toAppend);
            verify(mockReferralData, times(1)).append(toAppend);

				break
			}
			for _, index := range fieldIndexes {
				idx := indexesByName[index.Name]
				if idx == nil {
					idx = &Index{Name: index.Name}
					indexesByName[index.Name] = idx
					indexes = append(indexes, idx)
				}
				idx.Name = index.Name
				if idx.Class == "" {
					idx.Class = index.Class
				}
				if idx.Type == "" {
					idx.Type = index.Type
				}
				if idx.Where == "" {

    // Double.toString(Math.PI).length() == 17
    StringBuilder b = new StringBuilder((17 + 2) * (iMax + 1));
    b.append('[');
    for (int i = 0; ; i++) {
      b.append(longBitsToDouble(longs.get(i)));
      if (i == iMax) {
        return b.append(']').toString();
      }
      b.append(',').append(' ');
    }
  }

  /**
   * Saves the state to a stream (that is, serializes it).
   *

            if (event.getArtifact() != null) {
                trackingData.add(indent.toString() + event.getArtifact());
                indent.append("  ");
            }
            trackingData.add(indent + plugin.getGroupId() + ":" + plugin.getArtifactId() + ":" + plugin.getVersion());
            indent.append("  ");

            InputLocation location = plugin.getLocation("");
            if (location != null && location.getSource() != null) {

			for k := range mg.ExtraLabels {
				commonLabels = append(commonLabels, k)
			}
			for _, d := range mg.Descriptors {
				labels := slices.Clone(d.VariableLabels)
				labels = append(labels, commonLabels...)
				metric := metricDisplay{
					Name:   mg.MetricFQN(d.Name),
					Help:   d.Help,
					Type:   d.Type.String(),
					Labels: labels,
				}
				metrics = append(metrics, metric)
			}
		}
	}

            plugin.setArtifactId(tok[1]);
            plugin.setVersion(tok[2]);
            goal.append(tok[3]);

            // This won't be valid, but it constructs something easy to read in the error message
            for (int idx = 4; idx < tok.length; idx++) {
                goal.append(":").append(tok[idx]);
            }
        } else if (numTokens == 3) {

        out.append(format.normalizeFirstWord(s.substring(i, j)));
      } else {
        requireNonNull(out).append(format.normalizeWord(s.substring(i, j)));
      }
      out.append(format.wordSeparator);
      i = j + wordSeparator.length();
    }
    return (i == 0)
        ? format.normalizeFirstWord(s)
        : requireNonNull(out).append(format.normalizeWord(s.substring(i))).toString();
  }

    /* The following fails to compile:
     *
     * The method append(Iterable<? extends FluentIterableTest.A>) in the type
     * FluentIterable<FluentIterableTest.A> is not applicable for the arguments
     * (Iterable<FluentIterableTest.B>)
     */
    // FluentIterable.from(aIterable).append(bIterable);

    /* The following fails to compile:
     *

func (s *scratch) grow() {
	ndata := make([]byte, cap(s.data)*2)
	copy(ndata, s.data)
	s.data = ndata
}

// append single byte to scratch buffer
func (s *scratch) add(c byte) {
	if s.fill+1 >= cap(s.data) {
		s.grow()
	}

	s.data[s.fill] = c
	s.fill++
}

// append encoded rune to scratch buffer
func (s *scratch) addRune(r rune) int {
	if s.fill+utf8.UTFMax >= cap(s.data) {
		s.grow()
	}

        StringBuilder msg = new StringBuilder(message);
        problems.problems().forEach(problem -> msg.append("\n * ")
                .append(problem.getSeverity().name())
                .append(": ")
                .append(problem.getMessage()));
        return msg.toString();
    }

    /**
     * Returns the problem collector associated with this exception.
     *