public static boolean parseBoolean(String s) {
        if (s==null)
            throw new NullPointerException("Expected 'true' or 'false', got NULL");
        if (s.equalsIgnoreCase("false"))
            return false;
        if (s.equalsIgnoreCase("true"))
            return true;
        throw new IllegalArgumentException("Expected 'true' or 'false', got '" + s + "'");
    }
Returns true if the input string is case insensitive equal to "true" and
false if it is case insensitive equal to "false".
In any other case an exception is thrown.

@param  s the string to parse
@return true if s is "true", false if it is "false"
@throws IllegalArgumentException if s is not null but neither "true" or "false"
@throws NullPointerException if s is null
vespajlib/src/main/java/com/yahoo/text/BooleanParser.java