### Java Toolchain

The Gradle build uses [Java Toolchain](https://docs.gradle.org/current/userguide/toolchains.html) support to compile and execute tests across multiple versions of Java.

Available JDKs on your machine are automatically detected and wired for the various compile and test tasks.
Some tests require multiple JDKs to be installed on your computer, be aware of this if you make changes related to anything toolchains related.

    private Dependency injectDependency(Dependency d) {
        // we cannot set this directly in the MDO due to the interactions with dependency management
        return (d.getScope() == null || d.getScope().isEmpty()) ? d.withScope("compile") : d;
    }

    /**
     * Returns a list suited for the builders, i.e. null if not modified
     */
    private <T> List<T> injectList(List<T> list, Function<T, T> modifer) {
        List<T> newList = null;

   */
  private static MatchResult createMatchResult() {
    Matcher matcher = Pattern.compile(".").matcher("X");
    matcher.find();
    return matcher.toMatchResult();
  }

  private static final ClassToInstanceMap<Object> DEFAULTS =
      ImmutableClassToInstanceMap.builder()
          // primitives

   */
  private static MatchResult createMatchResult() {
    Matcher matcher = Pattern.compile(".").matcher("X");
    matcher.find();
    return matcher.toMatchResult();
  }

  private static final ClassToInstanceMap<Object> DEFAULTS =
      ImmutableClassToInstanceMap.builder()
          // primitives

        }
        stringBuilder
                .append(":")
                .append(dependency.getVersion())
                .append("@")
                .append(dependency.getScope() == null ? "compile" : dependency.getScope());
        if (dependency.isOptional()) {
            stringBuilder.append("[optional]");
        }
        if (!dependency.getExclusions().isEmpty()) {

            Collections.unmodifiableList(Arrays.asList("4.0.0", "4.1.0"));

    private static final Pattern EXPRESSION_NAME_PATTERN = Pattern.compile("\\$\\{(.+?)}");
    private static final Pattern EXPRESSION_PROJECT_NAME_PATTERN = Pattern.compile("\\$\\{(project.+?)}");

    private static final String ILLEGAL_FS_CHARS = "\\/:\"<>|?*";

    private static final String ILLEGAL_VERSION_CHARS = ILLEGAL_FS_CHARS;

		return err
	}

	cmd = exec.Command(goTool, "list", "-f", "{{.Target}}", "cmd/compile")
	cmd.Stderr = os.Stderr
	out, err = cmd.Output()
	if err != nil {
		return fmt.Errorf("%v: %w", cmd, err)
	}
	platformToolDir := filepath.Dir(string(bytes.TrimSpace(out)))
	if platformToolDir == "." {
		return errors.New("failed to locate cmd/compile for target platform")
	}

    return FluentIterable.from(ImmutableList.<Number>of());
  }

  /*
   * The following tests demonstrate the shortcomings of or() and test that the casting workaround
   * mentioned in the method Javadoc does in fact compile.
   */

  @SuppressWarnings("unused") // compilation test
  public void testSampleCodeError1() {
    Optional<Integer> optionalInt = getSomeOptionalInt();
    // Number value = optionalInt.or(0.5); // error
  }

            throw new IORuntimeException(e);
        }
    }

    protected String getTokenValue(final String tokenPattern, final String content) {
        final Matcher matcher = Pattern.compile(tokenPattern).matcher(content);
        if (matcher.find()) {
            if (logger.isDebugEnabled()) {
                logger.debug("Matched: {}", matcher.group());
            }

        }
        final Matcher matcher = getTagPattern().matcher(input);
        final StringBuffer sb = new StringBuffer();
        final Pattern attrPattern = Pattern.compile("\\s[^ ]+=\"([^\"]*)\"");
        while (matcher.find()) {
            final String tagStr = matcher.group();
            final Matcher attrMatcher = attrPattern.matcher(tagStr);