31 KiB
Release Notes
0.11.5
This patch release adds additional security guards against an ECDSA bug in Java SE versions 15-15.0.6, 17-17.0.2, and 18 (CVE-2022-21449) in addition to the guards added in the JJWT 0.11.3 release. This patch allows JJWT users using those JVM versions to upgrade to JJWT 0.11.5, even if they are unable to upgrade their JVM to patched/fixed JVM version in a timely manner. Note: if your application does not use these JVM versions, you are not exposed to the JVM vulnerability.
Note that the CVE is not a bug within JJWT itself - it is a bug within the above listed JVM versions, and the JJWT 0.11.5 release adds additional precautions within JJWT in case an application team is not able to upgrade their JVM in a timely manner.
However, even with these additional JJWT security guards, the root cause of the issue is the JVM, so it strongly recommended to upgrade your JVM to version 15.0.7, 17.0.3, or 18.0.1 or later to ensure the bug does not surface elsewhere in your application code or any other third party library in your application that may not contain similar security guards.
Issues included in this patch are listed in the JJWT 0.11.5 milestone.
Credits
Thank you to Neil Madden, the security researcher that first discovered the JVM vulnerability as covered in his Psychic Signatures in Java blog post. Neil worked directly with the JJWT team to provide these additional guards, beyond what was in the JJWT 0.11.3 release, and we're grateful for his help and collaboration in reviewing our fixes and for the additional tests he provided the JJWT team.
0.11.4
This patch release:
- Adds additional handling for rare JSON parsing exceptions and wraps them in a
JwtException
to allow the application to handle these conditions as JWT concerns. - Upgrades the
jjwt-jackson
module's Jackson dependency to2.12.6.1
. - Upgrades the
jjwt-orgjson
module's org.json:json dependency to20220320
. - Upgrades the
jjwt-gson
module's gson dependency to2.9.0
. - Upgrades the internal testing BouncyCastle version and any references in README documentation examples to
1.70
. - Contains various documentation and typo fixes.
The patch also makes various internal project POM and build enhancements to reduce repetition and the chance for stale references, and overall create a cleaner build with less warnings. It also ensures that CI testing builds and executes on all latest OpenJDK versions from Java 7 to Java 18 (inclusive).
Issues included in this patch are listed in the JJWT 0.11.4 milestone.
0.11.3
This patch release adds security guards against an ECDSA bug in Java SE versions 15-15.0.6, 17-17.0.2, and 18 (CVE-2022-21449). Note: if your application does not use these JVM versions, you are not exposed to the JVM vulnerability.
Note that the CVE is not a bug within JJWT itself - it is a bug within the above listed JVM versions. However, even with these additional JJWT security guards, the root cause of the issue is the JVM, so it strongly recommended to upgrade your JVM to version 15.0.7, 17.0.3, or 18.0.1 or later to ensure the bug does not surface elsewhere in your application code or any other third party library in your application that may not contain similar security guards.
Issues included in this patch are listed in the JJWT 0.11.3 milestone.
Backwards Compatibility Warning
In addition to additional protections against r or s values of zero in ECDSA signatures, this release also disables by default legacy DER-encoded signatures that might be included in an ECDSA-signed JWT. (DER-encoded signatures are not supported by the JWT RFC specifications, so they are not frequently encountered.)
However, if you are using an application that needs to consume such legacy JWTs (either produced by a very
early version of JJWT, or a different JWT library), you may re-enable DER-encoded ECDSA signatures by setting the
io.jsonwebtoken.impl.crypto.EllipticCurveSignatureValidator.derEncodingSupported
System property to the exact
String
value true
. For example:
System.setProperty("io.jsonwebtoken.impl.crypto.EllipticCurveSignatureValidator.derEncodingSupported", "true");
BUT BE CAREFUL: DO NOT set this System property if your application may run on one of the vulnerable JVMs noted above (Java SE versions 15-15.0.6, 17-17.0.2, and 18).
You may safely set this property to a String
value of true
on all other versions of the JVM if you need to
support these legacy JWTs, otherwise it is best to ignore (not set) the property entirely.
Credits
Thank you to Neil Madden, the security researcher that first discovered the JVM vulnerability as covered in his Psychic Signatures in Java blog post.
We'd also like to thank Toshiki Sasazaki, a member of LINE Corporation's Application Security Team as the first person to report the concern directly to the JJWT team, as well as for working with us during testing leading to our conclusions and subsequent 0.11.3 patch release.
0.11.2
This patch release:
- Allows empty JWS bodies to support RFC 8555 and similar initiatives. Pull Request 540
- Ensures OSGi environments can access JJWT implementation bundles (
jjwt-jackson
,jjwt-gson
, etc) as fragments tojjwt-api
bundle. Pull Request 580 - Rejects
allowedClockSkewSeconds
values that would cause numeric overflow. Issue 583 - Upgrades Jackson dependency to version
2.9.10.4
to address all known Jackson CVE vulnerabilities. Issue 585 - Updates
SecretKey
algorithm name validation to allow PKCS12 KeyStore OIDs in addition to JCA Names. Issue 588 - Enabled CI builds on JDK 14. Pull Request 590
- Adds missing parameters type to
Maps.add()
, which removes an unchecked type warning. Issue 591 - Ensures
GsonDeserializer
always usesUTF-8
for encoding bytes to Strings. Pull Request 592
All issues and PRs are listed in the Github JJWT 0.11.2 milestone.
0.11.1
This patch release:
- Upgrades the
jjwt-jackson
module's Jackson dependency to2.9.10.3
. - Fixes an issue when using Java 9+
Map.of
withJacksonDeserializer
that resulted in anNullPointerException
. - Fixes an issue that prevented the
jjwt-gson
.jar's seralizer/deserializer implementation from being detected automatically. - Ensures service implementations are now loaded from the context class loader, Services.class.classLoader, and the system classloader, the first classloader with a service wins, and the others are ignored. This mimics how
Classes.forName()
works, and how JJWT attempted to auto-discover various implementations in previous versions. - Fixes a minor error in the
Claims#getIssuedAt
JavaDoc.
0.11.0
This minor release:
-
Adds Google's Gson as a natively supported JSON parser. Installation instructions have been updated and new JJWT Gson usage guidelines have been added.
-
Updates the Jackson dependency version to 2.9.10 to address three security vulnerabilities in Jackson.
-
A new
JwtParserBuilder
interface has been added and is the recommended way of creating an immutable and thread-safe JwtParser instance. Mutable methods inJwtParser
will be removed before v1.0. Migration to the new signatures is straightforward, for example:Previous Version:
Jwts.parser() .requireAudience("string") .parse(jwtString)
Current Version:
Jwts.parserBuilder() .requireAudience("string") .build() .parse(jwtString)
-
Adds
io.jsonwebtoken.lang.Maps
utility class to make creation of maps fluent, as demonstrated next. -
Adds support for custom types when deserializing with Jackson. To use configure your parser:
Jwts.parserBuilder().deserializeJsonWith( new JacksonDeserializer( Maps.of("claimName", YourType.class).build() // <-- ) ).build()
-
Moves JSON Serializer/Deserializer implementations to a different package name.
io.jsonwebtoken.io.JacksonSerializer
->io.jsonwebtoken.jackson.io.JacksonSerializer
io.jsonwebtoken.io.JacksonDeserializer
->io.jsonwebtoken.jackson.io.JacksonDeserializer
io.jsonwebtoken.io.OrgJsonSerializer
->io.jsonwebtoken.orgjson.io.OrgJsonSerializer
io.jsonwebtoken.io.OrgJsonDeserializer
->io.jsonwebtoken.orgjson.io.OrgJsonDeserializer
A backward compatibility modules has been created using the
deprecated
classifier (io.jsonwebtoken:jjwt-jackson:0.11.0:deprecated
andio.jsonwebtoken:jjwt-orjson:0.11.0:deprecated
), if you are compiling against these classes directly, otherwise you will be unaffected.
Backwards Compatibility Warning
Due to this package move, if you are currently using one of the above four existing (pre 0.11.0) classes with compile
scope, you must either:
- change your code to use the newer package classes (recommended), or
- change your build/dependency configuration to use the
deprecated
dependency classifier to use the existing classes, as follows:
Maven
<dependency>
<groupId>io.jsonwebtoken</groupId>
<artifactId>jjwt-jackson</artifactId>
<version>0.11.0</version>
<classifier>deprecated</classifier>
<scope>compile</scope>
</dependency>
Gradle
compile 'io.jsonwebtoken:jjwt-jackson:0.11.0:deprecated'
Note: that the first option is recommended since the second option will not be available starting with the 1.0 release.
0.10.8
This patch release:
-
Ensures that SignatureAlgorithms
PS256
,PS384
, andPS512
work properly on JDK 11 and later without the need for BouncyCastle. Previous releases referenced a BouncyCastle-specific algorithm name instead of the Java Security Standard Algorithm Name ofRSASSA-PSS
. This release ensures the standard name is used moving forward. -
Fixes a backwards-compatibility bug when parsing compressed JWTs created from 0.10.6 or earlier using the
DEFLATE
compression algorithm.
0.10.7
This patch release:
- Adds a new Community section in the documentation discussing asking questions, using Slack and Gittr, and opening new issues and pull requests.
- Fixes a memory leak found in the DEFLATE compression codec implementation.
- Updates the Jackson dependency version to 2.9.9.1 to address three security vulnerabilities in Jackson: CVE-2019-12086, CVE-2019-12384, and CVE-2019-12814.
- Fixes a bug when Jackson is in the classpath but the
jjwt-jackson
.jar is not. - Fixes various documentation and typo fixes.
0.10.6
This patch release updates the jackson-databind version to 2.9.8 to address a critical security vulnerability in that library.
0.10.5
This patch release fixed an Android org.json
library compatibility issue.
0.10.4
This patch release fixed an outstanding issue with JCA name case-sensitivity that impacted Android that was not caught in the 0.10.3 release.
0.10.3
This is a minor patch release that fixed a key length assertion for SignatureAlgorithm.forSigningKey
that was
failing in Android environments. The Android dependencies and ProGuard exclusions documentation was updated as
well to reflect Android Studio 3.0 conventions.
0.10.2
This is a minor patch release that ensures the OrgJsonSerializer
and OrgJsonDeserializer
implementations are
compatible with Android's older org.json
API. Previously JJWT used newer org.json
APIs that are not
available on Android.
0.10.1
This is a minor point release that ensures the BouncyCastle dependency is optional and not pulled in as a transitive dependency into projects.
Internal implementation code (not impacting the JJWT API) and documentation was also updated to reflect that all Elliptic Curve algorithms are standard on the JDK and do not require Bouncy Castle.
Bouncy Castle is only needed when using PS256, PS384, and PS512 signature algorithms on < JDK 11. JDK 11 and later supports these algorithms natively.
0.10.0
This is a fairly large feature enhancement release that enables the following:
- Modular project structure resulting in pluggable JJWT dependencies (Issue 348)
- Auto-configuration for Jackson or JSON-Java JSON processors.
- Automatic SignatureAlgorithm selection based on specified signing Key.
- Algorithm and Key Strength Assertions
- Simplified Key generation
- Deterministic Base64(URL) support on all JDK and Android platforms
- Custom JSON processing
- Complete documentation
- and a bunch of other minor fixes and enhancements.
BACKWARDS-COMPATIBILITY NOTICE:
JJWT's new modular design utilizes distinctions between compile and runtime dependencies to ensure you only depend
on the public APIs that are safe to use in your application. All internal/private implementation classes have
been moved to a new jjwt-impl
runtime dependency.
If you depended on any internal implementation classes in the past, you have two choices:
-
Refactor your code to use the public-only API classes and interfaces in the
jjwt-api
.jar. Any functionality you might have used in the internal implementation should be available via newer cleaner interfaces and helper classes in that .jar. -
Specify the new
jjwt-impl
.jar not as a runtime dependency but as a compile dependency. This would make your upgrade to JJWT 0.10.0 fully backwards compatible, but you do so at your own risk. JJWT will make NO semantic version compatibility guarantees in thejjwt-impl
.jar moving forward. Semantic versioning will be very carefully adhered to in all other JJWT dependencies however.
0.9.1
This is a minor patch release that updates the Jackson dependency to 2.9.6 to address Jackson CVE-2017-17485.
0.9.0
This is a minor release that includes changes to dependencies and plugins to allow for building jjwt with Java 9. Javadocs in a few classes were updated as well to support proper linting in both Java 8 and Java 9.
0.8.0
This is a minor feature enhancement, dependency version update and build update release. We switched from Jacoco to OpenClover as OpenClover delivers a higher quality of test metrics. As an interim measure, we introduced a new repository that has an updated version of the coveralls-maven-plugin which includes support for Clover reporting to Coveralls. Once this change has been merged and released to the official coveralls-maven-plugin on maven central, this repository will be removed. The following dependencies were updated to the latest release version: maven compiler, maven enforcer, maven failsafe, maven release, maven scm provider, maven bundle, maven gpg, maven source, maven javadoc, jackson, bouncy castle, groovy, logback and powermock. Of significance, is the upgrade for jackson as a security issue was addressed in its latest release.
An addClaims
method is added to the JwtBuilder
interface in this release. It adds all given name/value pairs to
the JSON Claims in the payload.
Additional tests were added to improve overall test coverage.
0.7.0
This is a minor feature enhancement and bugfix release. One of the bug fixes is particularly important if using elliptic curve signatures, please see below.
Elliptic Curve Signature Length Bug Fix
Previous versions of JJWT safely calculated and verified Elliptic Curve signatures (no security risks), however, the signatures were encoded using the JVM's default ASN.1/DER format. The JWS specification however requires EC signatures to be in a R + S format. JJWT >= 0.7.0 now correctly represents newly computed EC signatures in this spec-compliant format.
What does this mean for you?
Signatures created from previous JJWT versions can still be verified, so your existing tokens will still be parsed correctly. HOWEVER, new JWTs with EC signatures created by JJWT >= 0.7.0 are now spec compliant and therefore can only be verified by JJWT >= 0.7.0 (or any other spec compliant library).
This means that if you generate JWTs using Elliptic Curve Signatures after upgrading to JJWT >= 0.7.0, you must also upgrade any applications that parse these JWTs to upgrade to JJWT >= 0.7.0 as well.
Clock Skew Support
When parsing a JWT, you might find that exp
or nbf
claims fail because the clock on the parsing machine is not
perfectly in sync with the clock on the machine that created the JWT. You can now account for these differences
(usually no more than a few minutes) when parsing using the new setAllowedClockSkewSeconds
method on the parser.
For example:
long seconds = 3 * 60; //3 minutes
Jwts.parser().setAllowedClockSkewSeconds(seconds).setSigningKey(key).parseClaimsJws(jwt);
This ensures that clock differences between machines can be ignored. Two or three minutes should be more than enough; it would be very strange if a machine's clock was more than 5 minutes difference from most atomic clocks around the world.
Custom Clock Support
Timestamps created during parsing can now be obtained via a custom time source via an implementation of
the new io.jsonwebtoken.Clock
interface. The default implementation simply returns new Date()
to reflect the time
when parsing occurs, as most would expect. However, supplying your own clock could be useful, especially during test
cases to guarantee deterministic behavior.
Android RSA Private Key Support
Previous versions of JJWT required RSA private keys to implement java.security.interfaces.RSAPrivateKey
, but Android
6 RSA private keys do not implement this interface. JJWT now asserts that RSA keys are instances of both
java.security.interfaces.RSAKey
and java.security.PrivateKey
which should work fine on both Android and all other
'standard' JVMs as well.
Library version updates
The few dependencies JWWT has (e.g. Jackson) have been updated to their latest stable versions at the time of release.
Issue List
For all completed issues, please see the 0.7.0 Milestone List
0.6.0
Enforce JWT Claims when Parsing
You can now enforce that JWT claims have expected values when parsing a compact JWT string.
For example, let's say that you require that the JWT you are parsing has a specific sub
(subject) value,
otherwise you may not trust the token. You can do that by using one of the require
methods on the parser builder:
try {
Jwts.parser().requireSubject("jsmith").setSigningKey(key).parseClaimsJws(s);
} catch(InvalidClaimException ice) {
// the sub field was missing or did not have a 'jsmith' value
}
If it is important to react to a missing vs an incorrect value, instead of catching InvalidClaimException
, you can catch either MissingClaimException
or IncorrectClaimException
:
try {
Jwts.parser().requireSubject("jsmith").setSigningKey(key).parseClaimsJws(s);
} catch(MissingClaimException mce) {
// the parsed JWT did not have the sub field
} catch(IncorrectClaimException ice) {
// the parsed JWT had a sub field, but its value was not equal to 'jsmith'
}
You can also require custom fields by using the require(fieldName, requiredFieldValue)
method - for example:
try {
Jwts.parser().require("myfield", "myRequiredValue").setSigningKey(key).parseClaimsJws(s);
} catch(InvalidClaimException ice) {
// the 'myfield' field was missing or did not have a 'myRequiredValue' value
}
(or, again, you could catch either MissingClaimException or IncorrectClaimException instead)
Body Compression
This feature is NOT JWT specification compliant, but it can be very useful when you parse your own tokens.
If your JWT body is large and you have size restrictions (for example, if embedding a JWT in a URL and the URL must be under a certain length for legacy browsers or mail user agents), you may now compress the JWT body using a CompressionCodec
:
Jwts.builder().claim("foo", "someReallyLongDataString...")
.compressWith(CompressionCodecs.DEFLATE) // or CompressionCodecs.GZIP
.signWith(SignatureAlgorithm.HS256, key)
.compact();
This will set a new zip
header with the name of the compression algorithm used so that parsers can see that value and decompress accordingly.
The default parser implementation will automatically decompress DEFLATE or GZIP compressed bodies, so you don't need to set anything on the parser - it looks like normal:
Jwts.parser().setSigningKey(key).parseClaimsJws(compact);
Custom Compression Algorithms
If the DEFLATE or GZIP algorithms are not sufficient for your needs, you can specify your own Compression algorithms by implementing the CompressionCodec
interface and setting it on the parser:
Jwts.builder().claim("foo", "someReallyLongDataString...")
.compressWith(new MyCompressionCodec())
.signWith(SignatureAlgorithm.HS256, key)
.compact();
You will then need to specify a CompressionCodecResolver
on the parser, so you can inspect the zip
header and return your custom codec when discovered:
Jwts.parser().setSigningKey(key)
.setCompressionCodecResolver(new MyCustomCompressionCodecResolver())
.parseClaimsJws(compact);
NOTE: Because body compression is not JWT specification compliant, you should only enable compression if both your JWT builder and parser are JJWT versions >= 0.6.0, or if you're using another library that implements the exact same functionality. This feature is best reserved for your own use cases - where you both create and later parse the tokens. It will likely cause problems if you compressed a token and expected a 3rd party (who doesn't use JJWT) to parse the token.
0.5.1
0.5
-
Android support! Android's built-in Base64 codec will be used if JJWT detects it is running in an Android environment. Other than Base64, all other parts of JJWT were already Android-compliant. Now it is fully compliant.
-
Elliptic Curve signature algorithms!
SignatureAlgorithm.ES256
,ES384
andES512
are now supported. -
Super convenient key generation methods, so you don't have to worry how to do this safely:
MacProvider.generateKey(); //or generateKey(SignatureAlgorithm)
RsaProvider.generateKeyPair(); //or generateKeyPair(sizeInBits)
EllipticCurveProvider.generateKeyPair(); //or generateKeyPair(SignatureAlgorithm)
The
generate
* methods that accept anSignatureAlgorithm
argument know to generate a key of sufficient strength that reflects the specified algorithm strength.
Please see the full 0.5 closed issues list for more information.
0.4
- Issue 8: Add ability to find signing key by inspecting the JWS values before verifying the signature.
This is a handy little feature. If you need to parse a signed JWT (a JWS) and you don't know which signing key was used to sign it, you can now use the new SigningKeyResolver
concept.
A SigningKeyresolver
can inspect the JWS header and body (Claims or String) before the JWS signature is verified. By inspecting the data, you can find the key and return it, and the parser will use the returned key to validate the signature. For example:
SigningKeyResolver resolver = new MySigningKeyResolver();
Jws<Claims> jws = Jwts.parser().setSigningKeyResolver(resolver).parseClaimsJws(compact);
The signature is still validated, and the JWT instance will still not be returned if the jwt string is invalid, as expected. You just get to 'see' the JWT data for key discovery before the parser validates. Nice.
This of course requires that you put some sort of information in the JWS when you create it so that your SigningKeyResolver
implementation can look at it later and look up the key. The standard way to do this is to use the JWS kid
('key id') field, for example:
Jwts.builder().setHeaderParam("kid", your_signing_key_id_NOT_THE_SECRET).build();
You could of course set any other header parameter or claims parameter instead of setting kid
if you want - that's just the default field reserved for signing key identification. If you can locate the signing key based on other information in the header or claims, you don't need to set the kid
field - just make sure your resolver implementation knows how to look up the key.
Finally, a nice SigningKeyResolverAdapter
is provided to allow you to write quick and simple subclasses or anonymous classes instead of having to implement the SigningKeyResolver
interface directly. For example:
Jws<Claims> jws = Jwts.parser().setSigningKeyResolver(new SigningKeyResolverAdapter() {
@Override
public byte[] resolveSigningKeyBytes(JwsHeader header, Claims claims) {
//inspect the header or claims, lookup and return the signing key
String keyId = header.getKeyId(); //or any other field that you need to inspect
return getSigningKey(keyId); //implement me
}})
.parseClaimsJws(compact);
0.3
- Issue 6: Parsing an expired Claims JWT or JWS (as determined by the
exp
claims field) will now throw anExpiredJwtException
. - Issue 7: Parsing a premature Claims JWT or JWS (as determined by the
nbf
claims field) will now throw aPrematureJwtException
.
0.2
More convenient Claims building
This release adds convenience methods to the JwtBuilder
interface so you can set claims directly on the builder without having to create a separate Claims instance/builder, reducing the amount of code you have to write. For example, this:
Claims claims = Jwts.claims().setSubject("Joe");
String compactJwt = Jwts.builder().setClaims(claims).signWith(HS256, key).compact();
can now be written as:
String compactJwt = Jwts.builder().setSubject("Joe").signWith(HS256, key).compact();
A Claims instance based on the specified claims will be created and set as the JWT's payload automatically.
Type-safe handling for JWT and JWS with generics
The following < 0.2 code produced a JWT as expected:
Jwt jwt = Jwts.parser().setSigningKey(key).parse(compact);
But you couldn't easily determine if the jwt
was a JWT
or JWS
instance or if the body was a Claims
instance or a plaintext String
without resorting to a bunch of yucky instanceof
checks. In 0.2, we introduce the JwtHandler
when you don't know the exact format of the compact JWT string ahead of time, and parsing convenience methods when you do.
JwtHandler
If you do not know the format of the compact JWT string at the time you try to parse it, you can determine what type it is after parsing by providing a JwtHandler
instance to the JwtParser
with the new parse(String compactJwt, JwtHandler handler)
method. For example:
T returnVal = Jwts.parser().setSigningKey(key).parse(compact, new JwtHandler<T>() {
@Override
public T onPlaintextJwt(Jwt<Header, String> jwt) {
//the JWT parsed was an unsigned plaintext JWT
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onClaimsJwt(Jwt<Header, Claims> jwt) {
//the JWT parsed was an unsigned Claims JWT
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onPlaintextJws(Jws<String> jws) {
//the JWT parsed was a signed plaintext JWS
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onClaimsJws(Jws<Claims> jws) {
//the JWT parsed was a signed Claims JWS
//inspect it, then return an instance of T (see returnVal above)
}
});
Of course, if you know you'll only have to parse a subset of the above, you can use the JwtHandlerAdapter
and implement only the methods you need. For example:
T returnVal = Jwts.parser().setSigningKey(key).parse(plaintextJwt, new JwtHandlerAdapter<Jwt<Header, T>>() {
@Override
public T onPlaintextJws(Jws<String> jws) {
//the JWT parsed was a signed plaintext JWS
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onClaimsJws(Jws<Claims> jws) {
//the JWT parsed was a signed Claims JWS
//inspect it, then return an instance of T (see returnVal above)
}
});
Known Type convenience parse methods
If, unlike above, you are confident of the compact string format and know which type of JWT or JWS it will produce, you can just use one of the 4 new convenience parsing methods to get exactly the type of JWT or JWS you know exists. For example:
//for a known plaintext jwt string:
Jwt<Header,String> jwt = Jwts.parser().parsePlaintextJwt(compact);
//for a known Claims JWT string:
Jwt<Header,Claims> jwt = Jwts.parser().parseClaimsJwt(compact);
//for a known signed plaintext JWT (aka a plaintext JWS):
Jws<String> jws = Jwts.parser().setSigningKey(key).parsePlaintextJws(compact);
//for a known signed Claims JWT (aka a Claims JWS):
Jws<Claims> jws = Jwts.parser().setSigningKey(key).parseClaimsJws(compact);