Replies: 11 comments 32 replies
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Hi @lfoppiano! Blackbird is a newer version of Afterburner. Afterburner is getting old and doesn't support Java 9+ well, so we switched to Blackbird in the 2.1.0 release to provide better support for recent Java versions. Java added a |
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Maybe it would be better to not activate blackbird for java 8. Previously, afterburner was activated only for java 8, so why not put condition around blackbird : if (!JavaVersion.isJava8()) {
mapper.registerModule(new BlackbirdModule());
}With this, it would be easy to manually activate afterburner for those who need it (blackbird was never positioned to be a good substitution for java 8 - it's compatible , but i'm sure afterburner would be faster). Besides, it is currently a bad default for java 8 because anyone launching even sample app on java 8 would be confused as it does not look like a warning. For production such default can't be used at all (or it would be a nightmare always explainig "why we have an exception on start"). The only way now to hide this "exception" in logs is to override ObjectMapper configuration, but this is, basically, required patching of the defaults. Isn't it better to fix defaults instead. |
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FYI, in past few days, I have tried multiple ways to suppress the message, but so far no success.
Last but not the least, this warning appears even when running IT because this Blackbird gets invoked via DropwizardTestSupport. |
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Does setting the level to
Is it being logged by the bootstrap logger? |
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I did not see any difference with OFF, warning message still gets logged on console.
No, as far as I can understand it is logged within ReflectionHack.java. Logger uses com.fasterxml.jackson.module.blackbird.BlackbirdModule to log the warning message. |
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Also getting this in a multi-service environment that we need to update dropwizard in across the board. I’m wondering what exactly are the implications of “not running optimally” - if it’s even a mildly noticeable performance hit then in our case it’s a big blocker. |
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For many of us it is not possible to upgrade java. Could you please tell us why don't you want to simply disable blackbird for java 8? It would be ideal solution for everyone (blackbird was never meant to be used for java 8, it's just compatible). Just mention in docs that java 8 users would have to actiavte afterburner manually. |
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Yes, I agree to above suggestion. I have tried to make use of afterburner manually by following steps mentioned by @zUniQueX in another thread, but I am still getting the warning from blackbird. I guess the registration for it is still lingering in some place. If I remove jackson-module-blackbird from shaded jar, things don't work and application itself does not start. I guess this is happening because, I have overridden the afterburner manually in initialize method of Application class. But it gets called after bootstrap object is created According to my understanding, only place to override is like shown below, do let me know if I am wrong: Is there any way around this issue? Detailed steps would certainly help others as well who are stuck on Java 8 due to multiple reasons. |
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@joschi we use Jackson extensively. Upgrading to Java 11/17 is not in the cards for us. These are some 30-40 microservices, Dropwizard |
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What's holding you back? If you want to get a performance boost for free, consider migrating to Java 11 or 17. |
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@joschi yes we are aware of benefits available if we move, but sadly our major part of applications use many components which do not play well with Java 11 or later. We do have a plan to do rewrite those, but it is a very big application and will take at least a year to move to Java 11. But biggest problem for us is to support older versions already out in customer environments. Our application is out in field for long time. We do need to provide bug fixes and security patches from time to time. They are on Java 8 and we don't have a control over when customer's will upgrade to new version when it gets released. Our customers have got very much eager lately on getting security fixes provided to them sooner and on timely basis. Hence the need to upgrade Dropwizard. |
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I showed up to upvote. If the 2.1.x branch is java8 compatible then it shouldn't be emitting this warning. |
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One more attempt to refresh the discussion: in case of afterburner it was ok to put jvm version condition around it, why is it not ok now? We just want to get rid of blackbird on java 8: if (!JavaVersion.isJava8()) {
mapper.registerModule(new BlackbirdModule());
}I'm really tired seeing this warning. Please, it is so simple change affecting only java 8 users Also, consider the default behaviour argument: "good defaults" was always a dropwizard selling point. Current default cause pain for java 8 users. I could make a PR if you want. I just can't understand (don't see) your arguments against this and so have no certainty it will be accepted. |
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@xvik There are more things to consider for changing the implementation now. Dropwizard always tries to ensure semantic versioning. If we would now change the implementation, this would be surprising. We can think of changing this in the next minor version. Additionally, we are working on/towards Dropwizard 3.x and 4.x. In this versions we will drop support for Java versions smaller than 11 and therefore would encourage all our users to upgrade to Java 11. Last but not least, the reflection hack Blackbird complains about is used by other libraries too. Many libraries still support Java 8 but rely on the |
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@zUniQueX, IMO it was rather surprising to see use of Blackbird for Java 8. In theory, it breaks semantic versioning. Dropwizard 2.1.x should have kept on using Afterburner to have full compatibility with Java 8. For Java 9+, Blackbird can be used like done currently. I feel it should be okay to move back to using Afterburner for Java 8 in next patch release. Does not makes sense to wait for next minor release. Jersey example you gave is very specific to Microprofile rest client. This affects only a certain portion of users of Jersey, not everyone. |
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@sandeepnkulkarni I checked (but on a very simple app), this workaround allows you to remove the warning. You might be referencing to @zUniQueX I agree with @sandeepk-veritas that it was already a breaking change: afterburner was a better option for java 8. In fact, the real problem is warning itself: I can't put app into production with it and I'll have to workaround this in any case. I really not much care if other logic tries to detect java 9 features, as long as it doesn't shout about it in my logs. This is a problem that must be fixed in a patch release: current behavuior under java8 is painful and, as you can see, anyone using java 8 have to workaround it. That is not normal. Bringing back afterburner would bring another dependency, useless for the majority of dropwizard users (using java 9+), so I don't think it is a good idea. But simply avoiding blackbird for java 8 would be an ideal solution: those who need afterburner could add it with just one line (compare how many lines we need now to get rid of blackbird). In dropwizard 2.0 we have afterburner enabled only for java 8 and java 9+ users have to enable blackbird manually. The proposed option "mirror" the old behaviour. I see it as a correct evolution (now old users should adapt). |
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@xvik, I tried the steps given by you again on a fresh Dropwizard application and warning does go away. Thanks a lot! |
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@xvik, I found that I had added call to bootstrap.setObjectMapper() to some level down where few things were getting set already. Hence was seeing the warning. Once I moved the call at the top of initialize(), things started working and no warning is visible now on console. Still seeing some warning messages when running IT, but is of less concern to us than having this warning message each time when we start the application. I believe we are seeing the warning because we are using a couple of deprecated testing APIs like ResourceTestRule. We have not migrated to alternates because we use TestNG not Junit. |
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I think we have different purposes in this discussion. To wrap this up: some users completely want to disable Blackbird and some only want to get rid of the generated warning. Clearly, Blackbird can be disabled by default only through modifications of the This method won't require any modifications of the |
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Thank you for the much better workaround! But still, it is a workaround, which means the problem still exists. Other moment is blackbird itself: it is not as good for java 8 as afterburner was and the only way to switch it back is pretty awkward. Avoiding blackbird registration for java 8 (only) would bring an easy choise for people still using java 8. As I mention before, in dw 2.0 afterburner was registered only for java 8 (9+ users may register blackbird manually or don't use any), and in dw 2.1 blackbird should be registered only for java 9+ (so java 8 users could register afterburner if they need or don't use any). It would be a comfortable default for everyone. The warning was a showstopper (it simply can't be allowed in production). Blackbird only may be a potentional problem for some projects on java 8. But, I believe, many will prefer to continue using afterbirning simply to avoid potential problems. |
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@xvik @sandeepk-veritas @zUniQueX What do you think of #5472? While we won't replace Jackson Blackbird in Dropwizard 2.1.x, this simplifies customizing the You'd have to extend |
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@joschi I like the idea and implementation - it would definitely simplify some scenarios. But I still think that by default blackbird should be activated only for java 9+. Regsitering it for all is a bad default. Consider common trail for java 8 user:
My point: current default is a bad default because It forces user for additional (completely predictable) steps. |
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I agree to @xvik. Good defaults should be there, users should not be forced to make overrides unnecessarily. Additional functionality provided by #5472 is a good step as well. |
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Just for completeness sake: I've tried to modify an existing public static class BlackbirdDisablingObjectMapper extends ObjectMapper {
protected BlackbirdDisablingObjectMapper(ObjectMapper src) {
super(src);
BeanDeserializerFactory beanDeserializerFactory = (BeanDeserializerFactory)this._deserializationContext.getFactory();
DeserializerFactoryConfig factoryConfig = beanDeserializerFactory.getFactoryConfig();
DeserializerFactoryConfig deserializerConfig = new DeserializerFactoryConfig();
if (factoryConfig.hasDeserializers()) {
for (Deserializers deserializers : factoryConfig.deserializers()) {
deserializerConfig = deserializerConfig.withAdditionalDeserializers(deserializers);
}
}
if (factoryConfig.hasKeyDeserializers()) {
for (KeyDeserializers keyDeserializers : factoryConfig.keyDeserializers()) {
deserializerConfig = deserializerConfig.withAdditionalKeyDeserializers(keyDeserializers);
}
}
if (factoryConfig.hasDeserializerModifiers()) {
for (BeanDeserializerModifier modifier : factoryConfig.deserializerModifiers()) {
if (!(modifier instanceof BBDeserializerModifier)) {
deserializerConfig = deserializerConfig.withDeserializerModifier(modifier);
}
}
}
if (factoryConfig.hasAbstractTypeResolvers()) {
for (AbstractTypeResolver abstractTypeResolver : factoryConfig.abstractTypeResolvers()) {
deserializerConfig = deserializerConfig.withAbstractTypeResolver(abstractTypeResolver);
}
}
if (factoryConfig.hasValueInstantiators()) {
for (ValueInstantiators valueInstantiators : factoryConfig.valueInstantiators()) {
deserializerConfig = deserializerConfig.withValueInstantiators(valueInstantiators);
}
}
DeserializerFactory newFactory = beanDeserializerFactory.withConfig(deserializerConfig);
this._deserializationContext = this._deserializationContext.with(newFactory);
BeanSerializerFactory beanSerializerFactory = (BeanSerializerFactory)this._serializerFactory;
SerializerFactoryConfig oldConfig = beanSerializerFactory.getFactoryConfig();
SerializerFactoryConfig config = new SerializerFactoryConfig();
if (oldConfig.hasSerializers()) {
for (Serializers serializers : oldConfig.serializers()) {
config = config.withAdditionalSerializers(serializers);
}
}
if (oldConfig.hasKeySerializers()) {
for (Serializers keySerializers: oldConfig.keySerializers()) {
config = config.withAdditionalKeySerializers(keySerializers);
}
}
if (oldConfig.hasSerializerModifiers()) {
for (BeanSerializerModifier modifier : oldConfig.serializerModifiers()) {
if (!(modifier instanceof BBSerializerModifier)) {
config = config.withSerializerModifier(modifier);
}
}
}
this._serializerFactory = ((BeanSerializerFactory) this._serializerFactory).withConfig(config);
this._registeredModuleTypes = this._registeredModuleTypes.stream().filter(moduleType -> !moduleType.equals(BlackbirdModule.class.getName())).collect(Collectors.toSet());
}
@Override
public ObjectMapper copy() {
_checkInvalidCopy(BlackbirdDisablingObjectMapper.class);
return new BlackbirdDisablingObjectMapper(this);
}
} |
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Kind of related, please leave your vote (or comments) in this poll: |
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We've partially reverted the change with the Jackson Afterburner and Blackbird modules in Dropwizard 2.1.1: While Jackson Blackbird is still the default (as a nudge for people to finally upgrade to Java 11 and later), Dropwizard will automatically prefer the Jackson Afterburner module if it's on the class path. |
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Release finally appeared in maven central. |
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Found an issue about Blackbird logs even with Afterburner being used in our application. Background: We are no longer getting exception when we start application on console like we used to get earlier. I had also added following in yaml:
But recently I thought it is completely unnecessary now, hence removed it. Now getting below logs from BlackbirdModule when we run our first API request. This is getting logged in log file only, not on console. I am also seeing one similar issue in our client module. Will provide information with more details. |
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I can confirm this behaviour. The generated JVM bytecode seems to do eager initialization of the Blackbird module. When we initialize it lazily, this exception won't get thrown. This can be performed e.g. with the following code: final Supplier<Module> acceleratorModule = modules.stream()
.filter(module -> "AfterburnerModule" .equals(module.getModuleName()))
.map(module -> (Supplier<Module>)(() -> module))
.findFirst()
.orElse(() -> {
try {
return BlackbirdModule.class.getConstructor().newInstance();
} catch (InstantiationException | IllegalAccessException | InvocationTargetException |
NoSuchMethodException e) {
throw new RuntimeException(e);
}
});
mapper.registerModule(acceleratorModule.get());@joschi I'm fine with our current implementation. But a few libraries may use |
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@zUniQueX thanks a lot for very quick response. |
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Further response on this issue will appreciated. |
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@zUniQueX do you have any plans to fix this issue in next release? |
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@sandeepk-veritas I'd rather concentrate of bringing Dropwizard 3.x and 4.x out of the door than working on this (cosmetic) issue. You could always provide a pull request against the |
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I'm running a dropwizard application which I've just updated to dropwizard 2.1. I'm also using
I'm using afterburner and jdk 8 and I get
com.fasterxml.jackson.module.blackbird.BlackbirdModule: Unable to find Java 9+ MethodHandles.privateLookupIn. Blackbird is not performing optimally!at startup. See below for the full stacktrace.Steps to reproduce the behavior:
I would like to understand what is the issue and how to solve it. Thank you in advance
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