fasterxml: Unrecognized token '***': was expecting ('true', 'false' or 'null')

fasterxml: Unrecognized token ‘open’: was expecting (‘true’, ‘false’ or ‘null’)

public class Test {
    static final ObjectMapper ObjMpr = new ObjectMapper();

    public static void main(String[] args) throws Exception {
        String s = "open";
        String s1 = ObjMpr.readValue(s, String.class);
        System.out.println(s1);
    }
}

Exception in thread "main" com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'open': was expecting ('true', 'false' or 'null') at [Source: java.io.StringReader@117c323d; line: 1, column: 9]