Integer claim fails with GSON

The following works with Jackson but fails with GSON because the claim value becomes non-integer during build.

I have

private static final int VERSION = 9; // an integer

I do

Jwts.builder()
                .claim("version", VERSION) // ends up as "version": 9 in the JSON
                .setExpiration(expires)
                .signWith(SECRET_KEY, SignatureAlgorithm.HS256)
                .compact();

and then

Jwts.parserBuilder()
                    .require("version", VERSION) // version is still 9 here
                    .setSigningKey(SECRET)
                    .build() // version seems to become 9.0
                    .parseClaimsJws(token); //fails with GSON

[oliverhausler]

I agree with you that looking at the decimal point . or the E is the right way to determine the number format. This is what I would have done as well. Also agree with what you say regarding floating point numbers and lost precision.

The problem with GSON I believe is that it doesn’t have a definition of what’s expected on the Java side, as we’re using Object here. If we would have the JWT explicitly coded as a class, this should work, because then GSON encounters a property which is Integer, Long, whatever, and it will properly convert it.

If I would write a JWT library with the things we have just found out, I would take the approach of defining an abstract JwtBase.java class with the security stuff and common properties, and then have the developer extend it with their custom JWT containing their custom claims. This I believe would work in GSON.

As for my part, I’ve been using Jackson, but thanks for discussing.

[stale[bot]]

Closed due to inactivity.