camel 3.8 generates REST routes twice - rest

Question

I faced a problem with camel REST routes when I switched from camel version 3.5.0 to version 3.8.0.
In the version 3.8.0 all routes from the REST service are generated twice! So at start of the camel context the exception is thrown:
Failed to start route route7 because of Multiple consumers for the same endpoint is not allowed: jetty:http://0.0.0.0:6060/start?httpMethodRestrict=GET
In detail:
I have a simple RouteBuilder to generate REST routes:
#Component
public class RestInterface extends RouteBuilder {
#Override
public void configure() throws Exception {
restConfiguration()
.component("jetty")
.host(urlInfo.getHost())
.port(urlInfo.getPort())
.bindingMode(RestBindingMode.json)
.dataFormatProperty("prettyPrint", "true")
.clientRequestValidation(true);
rest("/")
.get("/start").outType(RepositoryPackageInfo.class).to("direct:start")
.get("/stop").outType(RepositoryPackageInfo.class).to("direct:stop");
// ...
}
}
When I start this code with camel 3.8.0 I get following console output:
...
jetty-9.4.31.v20200723; built: 2020-07-23T17:57:36.812Z; git: 450ba27947e13e66baa8cd1ce7e85a4461cacc1d; jvm 11.0.4+11
Started o.e.j.s.ServletContextHandler#5f65e0c0{/,null,AVAILABLE}
Started ServerConnector#27b7204{HTTP/1.1, (http/1.1)}{0.0.0.0:6060}
Started #4095ms
Error starting CamelContext (camel-1) due to exception thrown: Failed to start route route7 because of Multiple consumers for the same endpoint is not allowed: jetty:http://0.0.0.0:6060/start?httpMethodRestrict=GET
org.apache.camel.FailedToStartRouteException: Failed to start route route7 because of Multiple consumers for the same endpoint is not allowed: jetty:http://0.0.0.0:6060/start?httpMethodRestrict=GET
...
Apache Camel 3.8.0 (camel-1) shutting down (timeout:45s)
Stopped ServerConnector#27b7204{HTTP/1.1, (http/1.1)}{0.0.0.0:6060}
Stopped o.e.j.s.ServletContextHandler#5f65e0c0{/,null,UNAVAILABLE}
Routes shutdown summary (total:40 stopped:40) <-------------- total 40 routes!!!
...
Stopped route8 (rest://get:/:/stop)
Stopped route7 (rest://get:/:/start)
Stopped route2 (rest://get:/:/stop)
Stopped route1 (rest://get:/:/start) <-------------- the routes "stop" and "start" are doubled!!!
...
If I run the same code with camel 3.5.0, the application starts without exceptions, and camel has only 38 routes:
etty-9.4.31.v20200723; built: 2020-07-23T17:57:36.812Z; git: 450ba27947e13e66baa8cd1ce7e85a4461cacc1d; jvm 11.0.4+11
Started o.e.j.s.ServletContextHandler#6cbb6c41{/,null,AVAILABLE}
Started ServerConnector#42172065{HTTP/1.1, (http/1.1)}{0.0.0.0:6060}
Started #4034ms
Route: route1 started and consuming from: jetty:http://0.0.0.0:6060/start
Route: route2 started and consuming from: jetty:http://0.0.0.0:6060/stop
...
Total 38 routes, of which 38 are started <-------------- total 38routes!!!
...
Completed initialization in 16 ms
Thank you in advance. I hope somebody can help me with this issue.
For completeness, here is a part of my pom.xml
<!-- Camel -->
<dependency>
<groupId>org.apache.camel.springboot</groupId>
<artifactId>camel-spring-boot-starter</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-rest</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jetty</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jackson</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-zipfile</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel.springboot</groupId>
<artifactId>camel-zipfile-starter</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel.springboot</groupId>
<artifactId>camel-bean-starter</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-management</artifactId>
<version>${camel.version}</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-test-spring</artifactId>
<version>${camel.version}</version>
<scope>test</scope>
</dependency>

Answer 1

Check if configure method on your RestInterface RouteBuilder is getting called more than once. Multiple calls cause duplicate RouteDefinitions to be added to the RouteBuilder instance which can lead to this error.
One way to solve this is to use boolean value in your RouteBuilder to check if configure method has already been called. Then use this value to early out or to throw an exception.
boolean isConfigured = false;
#Override
public void configure() throws Exception {
if(isConfigured){
return;
}
// Configure routes
isConfigured = true;
}
Encountered similar problem with Camel 2.x running in Karaf + OSGi where modifying config file lead to same error.
Basically configuring CamelContext service caused it to restart while the RouteBuilder services it referenced kept their state leading to situation where their configure method got called the second time leading to same error.