Application fails with `NoClassDefFoundError` on the latest boot and cloud version with OpenFeign

[Stummi]

When using the java-spring-jaeger library in a spring boot application with the latest spring boot and cloud version, and feign added, unit tests fail with an exception. Interestingly running the application seems to work, but the context cannot load in a unit test. (Edit: Seems I was wrong with that, the application does in fact also not start)

I tried to narrow it down the best I could. The error does not appear when I remove the opentracing lib from the dependencies, so probably related to it.

Caused by: java.lang.NoClassDefFoundError: org/springframework/cloud/openfeign/ribbon/LoadBalancerFeignClient
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017)
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)
	at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:821)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:719)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:642)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:600)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
	at io.opentracing.contrib.spring.cloud.feign.TracedFeignBeanFactory.from(TracedFeignBeanFactory.java:40)
	at io.opentracing.contrib.spring.cloud.feign.TraceFeignContext.addTracingClient(TraceFeignContext.java:64)
	at io.opentracing.contrib.spring.cloud.feign.TraceFeignContext.getInstance(TraceFeignContext.java:46)
	at org.springframework.cloud.openfeign.FeignClientFactoryBean.get(FeignClientFactoryBean.java:296)
	at org.springframework.cloud.openfeign.FeignClientFactoryBean.feign(FeignClientFactoryBean.java:110)
	at org.springframework.cloud.openfeign.FeignClientFactoryBean.getTarget(FeignClientFactoryBean.java:350)
	at org.springframework.cloud.openfeign.FeignClientFactoryBean.getObject(FeignClientFactoryBean.java:339)
	at org.springframework.cloud.openfeign.FeignClientsRegistrar.lambda$registerFeignClient$0(FeignClientsRegistrar.java:230)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.obtainFromSupplier(AbstractAutowireCapableBeanFactory.java:1231)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1173)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:564)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524)
	... 121 more
Caused by: java.lang.ClassNotFoundException: org.springframework.cloud.openfeign.ribbon.LoadBalancerFeignClient
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
	... 142 more

Sample application below. Let me know if there is more info I can provide

Update: after some digging into the issue it seems the error is in opentracing-contrib/java-spring-cloud. I opened a Pull Request there to fix the issue, so java-spring-jaeger just should update the dependency once the fix is released

---

Sample application:

DemoApplication.java

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

@SpringBootApplication
@EnableFeignClients
public class DemoApplication {
	public static void main(String[] args) {
		SpringApplication.run(DemoApplication.class, args);
	}
}

@Component
@FeignClient(name="test", url="https://api.github.com")
interface DemoApi {

}

@Service
class DemoService {
	@Autowired
	DemoService(DemoApi api) {}
}

DemoApplicationTests.java

package com.example.demo;

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class DemoApplicationTests {

	@Test
	void contextLoads() {
	}

}

build.gradle

plugins {
	id 'org.springframework.boot' version '2.4.5'
	id 'io.spring.dependency-management' version '1.0.11.RELEASE'
	id 'java'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {
	mavenCentral()
}

ext {
	set('springCloudVersion', "2020.0.2")
}

dependencies {
    implementation 'io.opentracing.contrib:opentracing-spring-jaeger-cloud-starter:3.3.1'
	implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

dependencyManagement {
	imports {
		mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
	}
}

test {
	useJUnitPlatform()
}