String currentJavaVersion = System.getProperty("java.version");
            if (!matchesVersion(requiredJavaVersion, currentJavaVersion)) {
                throw new IllegalStateException("Required Java version " + requiredJavaVersion
                        + " is not met by current version: " + currentJavaVersion);
            }
        }
    }

     */
    public static JavaVersion current() {
        if (currentJavaVersion == null) {
            currentJavaVersion = toVersion(System.getProperty("java.version"));
        }
        return currentJavaVersion;
    }

    static void resetCurrent() {
        currentJavaVersion = null;
    }

    public static JavaVersion forClassVersion(int classVersion) {

        // Verify it contains expected attributes
        def currentJavaVersion = JavaVersion.current().majorVersionNumber
        assertAttributes(apiElements, ["org.gradle.category": "library",
                                       "org.gradle.dependency.bundling": "external",
                                       "org.gradle.jvm.version": currentJavaVersion,
                                       "org.gradle.libraryelements": "jar",

        if (requiredJdkRange.startsWith("!")) {
            return !currentJavaVersion.startsWith(requiredJdkRange.substring(1));
        } else if (isRange(requiredJdkRange)) {
            return isInRange(currentJavaVersion, getRange(requiredJdkRange));
        } else {
            return currentJavaVersion.startsWith(requiredJdkRange);
        }
    }

        if (requiredJdkRange.startsWith("!")) {
            return !currentJavaVersion.startsWith(requiredJdkRange.substring(1));
        } else if (isRange(requiredJdkRange)) {
            return isInRange(currentJavaVersion, getRange(requiredJdkRange));
        } else {
            return currentJavaVersion.startsWith(requiredJdkRange);
        }
    }

        null       | null        | null            | null       | null          | currentJavaVersion() | currentJavaVersion() | currentJavaVersion()
    }

    @Issue("https://github.com/gradle/gradle/issues/22397")
    def "uses source and target compatibility from toolchain defined by forkOptions #forkOption"() {