This document is intended for helping you migrate your Apache Camel applications from version 2.x to 3.0.
Camel 3 supports Java 11. Support for Java 8 is best effort for the earlier versions of Camel 3. However at some time in the 3.x lifeline we will drop support for Java 8.
One of the biggest change is the modularization of camel-core. In Camel 2.x camel-core was one JAR file, which now has been splitup into many JARs as follows:
- camel-api
- camel-base
- camel-caffeine-lrucache
- camel-cloud
- camel-core
- camel-jaxp
- camel-main
- camel-management-api
- camel-management-impl
- camel-support
- camel-util
- camel-util-json
Maven users of Apache Camel can keep using the dependency camel-core which will have transitive dependency on all of its modules, and therefore no migration is needed. However users whom wants to trim the size of the classes on the classpath, can use fine grained Maven dependency on only the modules needed. You may find how to do that in the examples.
We have also modularized many of the core components and moved them out of camel-core to individual components:
- camel-attachments
- camel-bean
- camel-browse
- camel-controlbus
- camel-dataformat
- camel-dataset
- camel-direct
- camel-directvm
- camel-file
- camel-language
- camel-log
- camel-mock
- camel-properties
- camel-ref
- camel-rest
- camel-saga
- camel-scheduler
- camel-seda
- camel-stub
- camel-timer
- camel-validator
- camel-vm
- camel-xpath
- camel-xslt
- camel-zip-deflater
Support for multiple CamelContext's has been removed/deprecated and only 1 CamelContext per deployment is supported. The latter was not recommended anyway and was also not 100% implemented (for example in camel-cdi). For Camel 3 only 1 CamelContext per deployment is recommended and supported.
The context attribute on the various Camel annotations such as @EndpointInject, @Produce, @Consume etc has therefore been removed.
You should depend on camel-support and not camel-core directly.
The classes from org.apache.camel.impl that was intended to support Camel developers building custom components has been moved out of camel-core into camel-support into the org.apache.camel.support package. For example classes such as DefaultComponent, DefaultEndpoint etc has been moved and migration is necessary.
The LanguageAnnotation annotation class has been moved from package org.apache.camel.language to org.apache.camel.support.language.
All deprecated APIs and components from Camel 2.x has been removed in Camel 3.
The Camel Main class has been moved out of camel-core into camel-main so you should add that as dependency if you use Main.
The properties component has configuring custom prefix and suffix tokens removed as if in use, they had potential issues with clashing with simple languages and elsewhere. The default tokens are now hardcoded and always in use.
The properties component has some advanced options removed: propertyPrefix, propertySuffix, and fallbackToUnaugmented; these options was never really useable for end users anyway. The option propertiesResolver has also been removed as you should use PropertiesSource instead.
The properties component will now use OS environment variables as perferred value. This means you can set an OS environment variable which will override any property values that has been set in property files, JVM system properties etc. You can configure this with the environmentVariableMode option on the properties component.
We have removed all deprecated components from Camel 2.x, also including the old camel-http component. Instead you can use camel-http4.
We removed camel-jibx component which wasn't working on JDK 8.
The camel-zookeeper has its route policy functionality removed, instead use ZooKeeperClusterService or the camel-zookeeper-master component.
The camel-jetty component no longer supports producer (eg to) which has been removed, instead use camel-http4 component instead.
The test component has been renamed to dataset-test and moved out of camel-core into camel-dataset JAR.
We have also renamed camel-jetty9 to camel-jetty.
A new tracer has been implemented and the old tracer has been removed.
The new tracer logs messages at the org.apache.camel.Tracing logger name which is hardcoded. The format of the output is also updated to make it better. The tracer can be customized.
In JMX the BacklogTracer is no longer enabled by default, which you need to enable by setting backlogTracing=true on CamelContext. The backlog tracer and tracer are not the same. The former is used for capturing a backlog of traced messages which you can poll via JMX (needed for 3rd party tooling), where as tracer is writing to the log. Neither of them are enabled by default, and they must be enabled to be in use.
We have renamed the attribute headerName and propertyName in the XML DSL for the <setHeader> and <setProperty> EIPs, to be just name.
So migrate
<setHeader headerName="foo"><simple>Hello ${body}</simple></setHeader>
To
<setHeader name="foo"><simple>Hello ${body}</simple></setHeader>
And the same for <setProperty>.
Support for multiple CamelContext's has been removed, and therefore @ContextName has been removed. Instead use standard CDI annotations such as @Named and @ApplicationScoped.
The camel-script component has been removed and there is no support for javax.script, which is also deprecated in the JDK and to be removed from Java 11 onwards.
The attachments API (javax.activation) has been moved out of org.apache.camel.message into an extension org.apache.camel.attachment.AttachmentMessage from the camel-attachments JAR.
To use this API you can get it via the getMessage method on Exchange:
AttachmentMessage am = exchange.getMessage(AttachmentMessage.class);
am.addAttachment("myAtt", new DataHandler(...));
The fault API has been removed from org.apache.camel.Message as it was only used for SOAP-WS fault message. The camel-cxf and camel-spring-ws components for SOAP-WS has been modified to support fault messages from their components. The option handleFault has also been removed and you now need to turn this on as endpoint or component option on camel-cxf or camel-spring-ws.
The hasOut and getOut methods on Message has been deprecated in favour of using getMessage instead. (sidenote: The camel-core are still using these methods in a few places to be backwards compatible and rely on this logic as Camel was initially designed with the concepts of IN and OUT message inspired from the JBI and SOAP-WS specifications).
The simple language has removed the OUT message concepts eg ${out.body}.
Also the mock component has removed OUT message from its assertion API, eg
mock.message(0).outBody()...
Also the @OutHeaders annotation for bean parameter binding has been removed, instead use @Headers instead.
The mock component has been moved out of camel-core and as part of this work, we had to remove a number of methods on its assertion clause builder that were seldom in use.
If you are using the activemq-camel component, then you should migrate to use camel-activemq component, where the component name has changed from org.apache.activemq.camel.component.ActiveMQComponent to org.apache.camel.component.activemq.ActiveMQComponent.
The component camel-aws has been splitted in multiple components:
- camel-aws-cw
- camel-aws-ddb (which contains both ddb and ddbstreams components)
- camel-aws-ec2
- camel-aws-ecs
- camel-aws-eks
- camel-aws-iam
- camel-aws-kinesis (which contains both kinesis and kinesis-firehose components)
- camel-aws-kms
- camel-aws-lambda
- camel-aws-mq
- camel-aws-s3
- camel-aws-sdb
- camel-aws-ses
- camel-aws-sns
- camel-aws-sqs
- camel-aws-swf
So you'll have to add explicitly the dependencies for these components. From the OSGi perspective, there is still a camel-aws Karaf feature, which includes all the components features.
If you run Camel standalone with just camel-core as dependency, and you want JMX enabled out of the box, then you need to add camel-management-impl as dependency.
For using ManagedCamelContext you now need to get this an extension from CamelContext as follows:
ManagedCamelContext managed = camelContext.getExtension(ManagedCamelContext.class);
In Camel 2.x we have deprecated getProperties on CamelContext in favour of getGlobalOptions, so you should migrate to:
context.getGlobalOptions().put("CamelJacksonEnableTypeConverter", "true");
context.getGlobalOptions().put("CamelJacksonTypeConverterToPojo", "true");
... and in XML:
<globalOptions>
<globalOption key="CamelJacksonEnableTypeConverter" value="true"/>
<globalOption key="CamelJacksonTypeConverterToPojo" value="true"/>
</globalOptions>
The APIs on CamelContext has been reducded a bit to focus on relevant API for Camel end users. The advanced use-cases and for SPI and component developers, then some of the APIs from CamelContext has been moved to ExtendedCamelContext which you can access via adapt:
ExtendedCamelContext ecc = context.adapt(ExtendedCamelContext.class);
The Main class from camel-core, camel-spring and camel-cdi has been modified to only support a single CamelContext which was really its intention, but there was some old crufy code for multiple Camels. The method getCamelContextMap has been removed, and there is just a getCamelContext method now.
The ref attribute on @Consume, @Produce and @EndpointInject has been removed. Instead use the ref component in the uri attribute, eg uri = "ref:myName".
The uri attribute has been deprecated, instead use value, which allows a shorthand style, from using @Consume(uri = "jms:cheese") to @Consume("jms:cheese").
In Camel 2.x you could have 2 or more inputs to Camel routes, however this was not supported in all use-cases in Camel, and this functionality is seldom in use. This has also been deprecated in Camel 2.x. In Camel 3 we have removed the remaining code for specifying multiple inputs to routes, and its now only possible to specify exactly only 1 input to a route.
The default JSon library with the JSon dataformat has changed from XStream to Jackson.
The zip and gzip dataformat has been renamed to zipdeflater and gzipdeflater as they are for deflating using the zip/gzip compression; and not for working with zip/gzip files. Instead use camel-zipfile dataformat. Also these dataformats has been moved out of camel-core into camel-zip-deflater JAR. The XML and Java DSL has also been modified so you should migrate there too to use their new names. And if you use these data formats you need to add the camel-zip-deflater as dependency as they are no longer included as transitive dependency with camel-core.
The functionality to change the simple language tokens for start/end functions has been removed. The default tokens with ${xxx} and $simple{xxx} is now hardcoded (optimized). The functionality to change these tokens was never really in use and would only confuse Camel users if a new syntax are in use.
The following API changes may affect your existing Camel applications, which needs to be migrated.
The methods on CamelContext that are related to catalog has been moved into a new CatalogCamelContext interface, which you can access by adapting:
CatalogCamelContext ccc = context.adapt(CatalogCamelContext.class);
The loadRouteDefinitions and loadRestDefinitions on ModelCamelContext has been changed to addRouteDefinitions and addRestDefinitions to be aligned with the other methods. You can find loader methods on the ModelHelper utility class.
Most of the Camel exception classes has been migrated to be unchecked (eg extends RuntimeException).
Also the lifecycle of the start, stop and suspend, resume methods on Service and SuspendableService has been changed to not throw checked exceptions.
The class SimpleRegistry is moved from org.apache.camel.impl to org.apache.camel.support. Also you should favour using the org.apache.camel.support.DefaultRegistry instead. Also you should use the bind operation instead of put to add entries to the SimpleRegistry or DefaultRegistry.
The class CompositeRegistry and PropertyPlaceholderDelegateRegistry has been deleted. Instead use DefaultRegistry.
The classes from org.apache.camel.impl that was intended to support Camel developers building custom components has been moved out of camel-core into camel-support into the org.apache.camel.support package. If you have built custom Camel components that may have used some of these APIs you would then need to migrate. A large part of classes from the org.apache.camel.impl package have been moved to the org.apache.camel.impl.engine package in camel-base.
All the classes in org.apache.camel.util.component has been moved from the camel-core JAR to the package org.apache.camel.support.component in the camel-support JAR.
The method xslt has been removed from org.apache.camel.builder.AggregationStrategies. Instead use the XsltAggregationStrategy from camel-xslt JAR directly.
The getter/setter for bindingMode on RestEndpoint has been changed to use type org.apache.camel.spi.RestConfiguration.RestBindingMode from camel-api JAR. Instead of using this type class you can also call the setter method with string type instead.
The activemq-camel component has been moved from ActiveMQ into Camel and it is now called camel-activemq, the package has been changed accordingly to org.apache.camel.component.activemq
The method includeRoutes on RouteBuilder has been removed. This functionality was not fully in use and was deprecated in Camel 2.x.
The exception PredicateValidationException has been moved from package org.apache.camel.processor.validation to org.apache.camel.support.processor.validation.PredicateValidationException.
The class org.apache.camel.util.toolbox.AggregationStrategies has been moved to org.apache.camel.builder.AggregationStrategies.
The class org.apache.camel.processor.aggregate.AggregationStrategy has been moved to org.apache.camel.AggregationStrategy.
The class org.apache.camel.processor.loadbalancer.SimpleLoadBalancerSupport has been removed, instead use org.apache.camel.processor.loadbalancer.LoadBalancerSupport.
The class org.apache.camel.management.JmxSystemPropertyKeys has been moved to org.apache.camel.api.management.JmxSystemPropertyKeys.
The class org.apache.camel.builder.xml.XPathBuilder has been moved to org.apache.camel.language.xpath.XPathBuilder and in the camel-xpath JAR.
The annotation org.apache.camel.language.XPath has been moved to org.apache.camel.language.xpath.XPath and in the camel-xpath JAR.
The exception org.apache.camel.builder.xml.InvalidXPathExpression has been renamed to org.apache.camel.language.xpath.InvalidXPathException and in the camel-xpath JAR.
The annotation org.apache.camel.language.Bean has been moved to org.apache.camel.language.bean.Bean and in the camel-bean JAR.
The annotation org.apache.camel.language.Simple has been moved to org.apache.camel.language.simple.Simple.
The annotation org.apache.camel.Constant has been removed, use @Simple instead.
The annotation org.apache.camel.language.SpEL has been moved to org.apache.camel.language.spel.SpEL and in the camel-spring JAR.
The annotation org.apache.camel.InvokeOnHeader and org.apache.camel.InvokeOnHeaders has been moved to the org.apache.camel.spi package.
Rename various APIs in camel-core to fix the typo chiper to cipher.
The classes ReloadStrategySupport and FileWatcherReloadStrategy has been removed.
The MessageHistoryFactory interface has some options to filter and copy the message and a slight change in its API.
Removed TypeConverterAware as you shoudld instead use Exchange as parameter to the type converter method.
The Component and DataFormat interfaces now extend Service as components and data formats should also have service contract to manage their lifecycle. The default base classes already implements these interfaces.
If you are using camel-test and override the createRegistry method, for example to register beans from the JndiRegisty class, then this is no longer necessary, and instead
you should just use the bind method from the Registry API which you can call directly from CamelContext, such as:
context.getRegistry().bind("myId", myBean);
The startRoute, stopRoute, suspendRoute, resumeRoute, getRouteStatus, and other related methods on CamelContext has been moved to the RouteController as shown below:
context.getRouteController().startRoute("myRoute");
All the events from package org.apache.camel.management.event has been moved to the class org.apache.camel.spi.CamelEvent as sub-classes, for example the event for CamelContext started would be CamelEvent.CamelContextStartedEvent.
Testing using adviceWith currently needs to be changed from:
context.getRouteDefinition("start").adviceWith(context, new RouteBuilder() {
...
}
to using style:
RouteReifier.adviceWith(context.getRouteDefinition("start"), context, new RouteBuilder() {
...
}
We are planning on making this easier in 3.0.0-M2 onwards.
The class JNDIContext has been moved from org.apache.camel.util.jndi.JNDIContext in the camel-core JAR to org.apache.camel.support.jndi.JNDIContext and moved to the camel-support JAR.
The circuitBreaker load-balancer EIP was deprecated in Camel 2.x, and has been removed. Instead use Hystrix EIP as the load-balancer.
The class ThreadPoolRejectedPolicy has been moved from org.apache.camel.ThreadPoolRejectedPolicy to org.apache.camel.util.concurrent.ThreadPoolRejectedPolicy.
The simple language property function was deprecated in Camel 2.x and has been removed. Use exchangeProperty as function name.
The terser language has been renamed from terser to hl7terser.
The classes from org.apache.camel.util.jsse has been moved to org.apache.camel.support.jsse.
The class AsyncProcessorHelper has been moved from org.apache.camel.util.AsyncProcessorHelper in the camel-core JAR to org.apache.camel.support.AsyncProcessorHelper and moved to the camel-support JAR.
The class AsyncProcessorConverterHelper has been moved from org.apache.camel.util.AsyncProcessorConverterHelper in the camel-core JAR to org.apache.camel.support.AsyncProcessorConverterHelper and moved to the camel-support JAR.
The class CamelContextHelper has been moved from org.apache.camel.util.CamelContextHelper in the camel-core JAR to org.apache.camel.support.CamelContextHelper and moved to the camel-support JAR.
The class EndpointHelper has been moved from org.apache.camel.util.EndpointHelper in the camel-core JAR to org.apache.camel.support.EndpointHelper and moved to the camel-support JAR.
The class EventHelper has been moved from org.apache.camel.util.EventHelper in the camel-core JAR to org.apache.camel.support.EventHelper and moved to the camel-support JAR.
The class ExchangeHelper has been moved from org.apache.camel.util.ExchangeHelper in the camel-core JAR to org.apache.camel.support.ExchangeHelper and moved to the camel-support JAR.
The class GZIPHelper has been moved from org.apache.camel.util.GZIPHelper in the camel-core JAR to org.apache.camel.support.GZIPHelper and moved to the camel-support JAR.
The class JsonSchemaHelper has been moved from org.apache.camel.util.JsonSchemaHelper in the camel-core JAR to org.apache.camel.support.JsonSchemaHelper and moved to the camel-support JAR.
The class MessageHelper has been moved from org.apache.camel.util.MessageHelper in the camel-core JAR to org.apache.camel.support.MessageHelper and moved to the camel-support JAR.
The class ObjectHelper has been moved from org.apache.camel.util.ObjectHelper in the camel-core JAR and splitted into org.apache.camel.support.ObjectHelper and moved to the camel-support JAR and into org.apache.camel.util.ObjectHelper and moved to the camel-util JAR. This has been done to isolate the methods using camel-api JAR: those method are in the camel-support JAR, the other in the camel-util JAR.
The class PlatformHelper has been moved from org.apache.camel.util.PlatformHelper in the camel-core JAR to org.apache.camel.support.PlatformHelper and moved to the camel-support JAR.
The class PredicateAssertHelper has been moved from org.apache.camel.util.PredicateAssertHelper in the camel-core JAR to org.apache.camel.support.PredicateAssertHelper and moved to the camel-support JAR.
The class ResolverHelper has been moved from org.apache.camel.util.ResolverHelper in the camel-core JAR to org.apache.camel.support.ResolverHelper and moved to the camel-support JAR.
The class ResourceHelper has been moved from org.apache.camel.util.ResourceHelper in the camel-core JAR to org.apache.camel.support.ResourceHelper and moved to the camel-support JAR.
The class RestProducerFactoryHelper has been moved from org.apache.camel.spi.RestProducerFactoryHelper in the camel-core JAR to org.apache.camel.support.RestProducerFactoryHelper and moved to the camel-support JAR.
The class ServiceHelper has been moved from org.apache.camel.util.ServiceHelper in the camel-core JAR to org.apache.camel.support.service.ServiceHelper and moved to the camel-api JAR.
The class UnitOfWorkHelper has been moved from org.apache.camel.util.UnitOfWorkHelper in the camel-core JAR to org.apache.camel.support.UnitOfWorkHelper and moved to the camel-support JAR.
The class FileIdempotentRepository has been moved from org.apache.camel.processor.idempotent.FileIdempotentRepository in the camel-core JAR to org.apache.camel.support.processor.idempotent.FileIdempotentRepository and moved to the camel-suppor JAR.
The class MemoryIdempotentRepository has been moved from org.apache.camel.processor.idempotent.MemoryIdempotentRepository in the camel-core JAR to org.apache.camel.support.processor.idempotent.MemoryIdempotentRepository and moved to the camel-suppor JAR.
The class org.apache.camel.impl.RoutePolicySupport has been moved to org.apache.camel.support.RoutePolicySupport. The return type from startConsumer and stopConsumer has been changed from boolean to void as they always returned true before.
The class org.apache.camel.impl.ThrottlingInflightRoutePolicy has been moved to org.apache.camel.throttling.ThrottlingInflightRoutePolicy
The class XsltAggregationStrategy has been moved from org.apache.camel.builder.XsltAggregationStrategy in the camel-core JAR to org.apache.camel.component.xslt.XsltAggregationStrategy and moved to the camel-xslt JAR.
When using the option groupedExchange on the aggregator EIP then the output of the aggregation is now longer also stored in the exchange property Exchange.GROUPED_EXCHANGE. This behaviour was already deprecated from Camel 2.13 onwards.
The @FallbackConverter annotation has been removed, and you should use @Converter(fallback = true) instead. Also you can set @Converter(loader = true) on the converter class to allow Camel to generate source code for loading type converters in a faster way.
The APIs that could find, and explain EIPs, components, endpoints etc has been removed. These APIs have little value for production runtimes, and you can obtain this kind of information via the camel-catalog. Also the related Camel Karaf commands that used these APIs has been removed.
The default for use breadcrumbs has been changed from true to false.
The ProducerTemplate and ConsumerTemplate now fails when being used, if CamelContext has not been started first.
The XML DSL has been changed slightly.
The custom load balancer EIP has changed from <custom> to <customLoadBalancer>
The XMLSecurity data format has renamed the attribute keyOrTrustStoreParametersId to keyOrTrustStoreParametersRef in the <secureXML> tag.
The <zipFile> data format has been renamed to <zipfile>.
The camel-maven-plugin has been splitup into two maven plugins:
- camel-maven-plugin
- camel-report-maven-plugin
The former has the run goal, which is intended for quickly running Camel applications standalone.
The camel-report-maven-plugin has the validate and route-coverage goals which is used for generating reports of your Camel projects such as validating Camel endpoint URIs and route coverage reports, etc.
There is an issue with MDC logging and correctly transfering the Camel breadscrumb id's under certain situations with routing over asynchronous endpoints, due to the internal routing engine refactorings. This change also affects the camel-zipkin component, which may not correctly transfer the span id's when using MDC logging as well.
The tracer feature does not work (the implementation from Camel 2.x was deprecated), and we plan to implement a new and improved tracer.