Misleading exception for unquoted String parsing

[mazkozi]

Hi,

I am using Jakcson Databind v2.9.9. I have following code that fails.

public class Test {

    public static void main(String[] args) throws IOException {
        String test = "test";
        Reader inputString = new StringReader(test);
        ObjectMapper objectMapper = new ObjectMapper();
        Object o = objectMapper.readValue(inputString, objectMapper.constructType(SimpleType.construct(String.class)));
        System.out.println("Output: " + o);
    }
}

Exception is:

> Exception in thread "main" com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'test': was expecting 'null', 'true', 'false' or NaN
 at [Source: (StringReader); line: 1, column: 9]
	at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1804)
	at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:703)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._reportInvalidToken(ReaderBasedJsonParser.java:2853)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._reportInvalidToken(ReaderBasedJsonParser.java:2831)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._matchToken2(ReaderBasedJsonParser.java:2628)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._matchToken(ReaderBasedJsonParser.java:2606)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._matchTrue(ReaderBasedJsonParser.java:2564)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser.nextToken(ReaderBasedJsonParser.java:725)
	at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:4141)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4000)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3063)
	at com.feign.orch.Test.main(Test.java:16)

Can some one please help?

[cowtowncoder]

Your input:

test

is not valid JSON: Strings must be quoted in double-quotes. This is what exception points out.

[plokhotnyuk]

@cowtowncoder it seems that an error message is misleading

[cowtowncoder]

@plokhotnyuk I'm sure there are always ways to improve error messages, but what is the problem with this one?

[plokhotnyuk]

@cowtowncoder it looks like enumeration of all ałowed tokens, but misses to mention that strings or numbers are expected here too.

[cowtowncoder]

@plokhotnyuk Ok I see, yes, that could be argued. Rationale for existing exception is simply that anything that starts with a letter must be unquoted keyword, and thereby Strings (start with double-quote) and Numbers (digit, comma, or minus) do not count. But I can see why that assumes some context from recipient should not be assumed.