Creating a JWT (using the jose4j library - https://bitbucket.org/b_c/jose4j/wiki/Home)

Create_JWT_With_Subject.txt

//exception handling excluded to avoid verbosity

RsaJsonWebKey rsaJsonWebKey = RsaKeyProducer.produce();

JwtClaims claims = new JwtClaims();
claims.setSubject("user1");

JsonWebSignature jws = new JsonWebSignature();
jws.setPayload(claims.toJson());
jws.setKey(rsaJsonWebKey.getPrivateKey());
jws.setAlgorithmHeaderValue(AlgorithmIdentifiers.RSA_USING_SHA256);

String jwt = jws.getCompactSerialization();

//the encoded JWT

eyJhbGciOiJSUzI1NiJ9
.eyJzdWIiOiJ1c2VyMSJ9
.HG9GCQPuC6w6pulbYE2uurCzpEwoWvz_8Ps5ZjgtfomyY4LWacDEzlHLnyMj9H7aqgcePC7_4l2wDXQV-S0BQRsIZfJeUUmWxlTlLzvKZr_2eEx00YZPPFZNoFCfwB-ajLHLLenROy4aSjPo_Vg9o7N-p0DZ1yZQoJhkvoVJgkhX9FeAf65kIZkbuJC9dmVkzXSOpVf4GZeCpNDJJYSo6IAnL3UEoWek6V9BtWgV-a4xvydp7vxkdDXmzmalGLYuWbuVG7rWcbWwSfsg38iEG-mqptqA_Kzk1VmjwWNo_BfvLuzjzuosqi732-5SRzBP-2zqGghBqMYsGgkqkH2n7A

//human readable format

{
  "alg": "RS256" //header
}

{
  "sub": "user1" //claim payload
}