collector.setSource("SOURCE_PROBLEM2");
        collector.add(null, "PROBLEM2", -1, -1, null);

        collector.setSource("SOURCE_PROBLEM3");
        collector.add(null, "PROBLEM3", -1, -1, null);

        assertEquals("", collector.getProblems().get(0).getSource());
        assertEquals("SOURCE_PROBLEM2", collector.getProblems().get(1).getSource());

     *
     * @return The hint about the source of the problem or an empty string if unknown, never {@code null}.
     */
    String getSource();

    /**
     * Gets the one-based index of the line containing the problem. The line number should refer to some text file that
     * is given by {@link #getSource()}.
     *
     * @return The one-based index of the line containing the problem or a non-positive value if unknown.
     */

            if (req.getLocation().getSource() != null) {
                modelId = req.getLocation().getSource().getModelId();
                source = req.getLocation().getSource().getLocation();
            }
        }

        if (modelId == null) {
            modelId = getModelId();
            source = getSource();
        }

     *
     * @return The hint about the source of the problem or an empty string if unknown, never {@code null}.
     */
    String getSource();

    /**
     * Gets the one-based index of the line containing the problem. The line number should refer to some text file that
     * is given by {@link #getSource()}.
     *
     * @return The one-based index of the line containing the problem or a non-positive value if unknown.
     */

    @Override
    public String getLocation() {
        StringBuilder buffer = new StringBuilder(256);

        if (!getSource().isEmpty()) {
            if (!buffer.isEmpty()) {
                buffer.append(", ");
            }
            buffer.append(getSource());
        }

        if (getLineNumber() > 0) {
            if (!buffer.isEmpty()) {
                buffer.append(", ");
            }

// Tests getSource().
func TestGetSource(t *testing.T) {
	currentSource := func() string { return getSource(2) }
	gotSource := currentSource()
	// Hard coded line number, 34, in the "expectedSource" value
	expectedSource := "[namespace-lock_test.go:34:TestGetSource()]"
	if gotSource != expectedSource {
		t.Errorf("expected : %s, got : %s", expectedSource, gotSource)
	}
}

// Test lock race

    @Override
    public String getLocation() {
        StringBuilder buffer = new StringBuilder(256);

        if (!getSource().isEmpty()) {
            if (!buffer.isEmpty()) {
                buffer.append(", ");
            }
            buffer.append(getSource());
        }

        if (getLineNumber() > 0) {
            if (!buffer.isEmpty()) {
                buffer.append(", ");
            }

                            md.getClassifier(),
                            edge.getArtifactUri(),
                            edge.getSource() == null
                                    ? ""
                                    : edge.getSource().getMd().toString(),
                            edge.isResolved(),
                            edge.getTarget() == null
                                    ? null

            if (request.getPath().isPresent()) {
                Path path = request.getPath().get();
                res = builder.build(path.toFile(), req);
            } else if (request.getSource().isPresent()) {
                Source source = request.getSource().get();
                ModelSource2 modelSource = new SourceWrapper(source);
                res = builder.build(modelSource, req);
            } else {

     * @return the hint about the source of the problem or an empty string if unknown, never {@code null}
     */
    @Nonnull
    String getSource();

    /**
     * Gets the one-based index of the line containing the problem. The line number should refer to some text file that
     * is given by {@link #getSource()}.
     *
     * @return the one-based index of the line containing the problem or a non-positive value if unknown
     */