Method fromString

server/src/main/java/org/elasticsearch/Version.java:384–393

Returns the version given its string representation, current version if the argument is null or empty

(String version)

     * Returns the version given its string representation, current version if the argument is null or empty
     */
    public static Version fromString(String version) {
        if (!Strings.hasLength(version)) {
            return Version.CURRENT;
        }
        final Version cached = STRING_TO_VERSION.get(version);
        if (cached != null) {
            return cached;
        }
        return fromStringSlow(version);
    }

    private static Version fromStringSlow(String version) {
        final boolean snapshot; // this is some BWC for 2.x and before indices