UnsupportedClassVersionError when running on Java 8

[hiji]

Description

In a Java 8 environment, registering a Logbook with the JAX-RS client (implemented in Jersey) and sending a request generated an UnsupportedClassVersionError.

In the README, following is written as Dependencies.

Java 8 (for Spring 6 / Spring Boot 3 Java 17 is required)

After investigating the cause, it seems that Paguro:3.10.3, on which logbook-api depends, is compiled with Java 11.

Is Java 11 required to use Logbook?

java.lang.UnsupportedClassVersionError: org/organicdesign/fp/collections/ImSortedMap has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:756)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:473)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:425)
	at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:271)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:247)
	at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239)
	at org.zalando.logbook.HttpHeaders.empty(HttpHeaders.java:79)
	at org.zalando.logbook.HttpHeaders.of(HttpHeaders.java:87)
	at org.zalando.logbook.jaxrs.LocalRequest.getHeaders(LocalRequest.java:145)
	at org.zalando.logbook.Cache.lambda$get$0(Cache.java:16)
	at java.util.concurrent.atomic.AtomicReference.updateAndGet(AtomicReference.java:179)
	at org.zalando.logbook.Cache.get(Cache.java:15)
	at org.zalando.logbook.CachingHttpRequest.getHeaders(CachingHttpRequest.java:20)
	at org.zalando.logbook.FilteredHttpRequest.<init>(FilteredHttpRequest.java:30)
	at org.zalando.logbook.DefaultLogbookFactory.lambda$combine$2(DefaultLogbookFactory.java:63)
	at org.zalando.logbook.RequestFilter.lambda$merge$1(RequestFilter.java:19)
	at org.zalando.logbook.DefaultLogbook.process(DefaultLogbook.java:38)
	at org.zalando.logbook.DefaultLogbook.process(DefaultLogbook.java:27)
	at org.zalando.logbook.jaxrs.LogbookClientFilter.filter(LogbookClientFilter.java:35)
	at org.glassfish.jersey.client.ClientFilteringStages$RequestFilteringStage.apply(ClientFilteringStages.java:144)
	at org.glassfish.jersey.client.ClientFilteringStages$RequestFilteringStage.apply(ClientFilteringStages.java:132)
	at org.glassfish.jersey.process.internal.Stages.process(Stages.java:147)
	at org.glassfish.jersey.client.ClientRuntime.invoke(ClientRuntime.java:297)

Expected Behavior

Log output when sending HTTP request with JAX-RS client.

Actual Behavior

UnsupportedClassVersionError is thrown when sending HTTP request with JAX-RS client.

Possible Fix

Steps to Reproduce

1. Set java.version to 1.8 in Maven project.
2. Send HTTP request with JAX-RS client (implemented by Jersery) that has registered Logbook.

Context

I want to use Logbook in project that uses Java 8.

Your Environment

• Version used: 2.16.0
• Link to your project:

[msdousti]

I'll try to remove Paguro from project. Please note that changes will be applied to version 3. (To be released soon)

[hiji]

@msdousti Thanks! I will try it when version 3 is released.