Cannot use 3rd party library which requires Guava 31.1 version due to incompatibility with Corda's Guava 28.0

[adamturski]

I want to add integration with Google PubSub 1.124.2 in Corda 4

compile("com.google.cloud:google-cloud-pubsub:1.124.2")

Simply I have a @CordaService which has a method to publish something to Google PubSub. It builds fine but in runtime I get this error:

Caused by: java.lang.NoSuchMethodError: com.google.common.collect.ImmutableMap$Builder.buildKeepingLast()Lcom/google/common/collect/ImmutableMap;

I found that PubSub library has a dependency
com.google.guava:guava:31.1-jre
where ImmutableMap.buildKeepingLast method was added.

In runtime I checked that ImmutableMap was loaded from here:
(file:/home/xxx/.capsule/apps/net.corda.node.CordaEnterprise_4.6.1/guava-28.0-jre.jar )

Why is that? Why Corda dependency was used instead of workflows dependency?

Code to reproduce:
workflows build gradle

compile("com.google.cloud:google-cloud-pubsub:1.124.2")
compile("com.google.guava:guava:31.1-jre")

Corda Service:

import com.google.api.core.ApiFuture
import com.google.cloud.pubsub.v1.Publisher
import com.google.protobuf.ByteString
import com.google.pubsub.v1.PubsubMessage
import com.google.pubsub.v1.TopicName
import net.corda.core.node.AppServiceHub
import net.corda.core.node.services.CordaService
import net.corda.core.serialization.SingletonSerializeAsToken
import net.corda.core.utilities.loggerFor
import java.util.concurrent.TimeUnit

@CordaService
class EventBusPublisher(private val serviceHub: AppServiceHub) : SingletonSerializeAsToken() {

    companion object {
        val logger = loggerFor<EventBusPublisher>()
    }

    fun publish(message: String) {
        logger.info("Publishing message to event bus: $message")

        val topicName = TopicName.of("fragmos", "corda.event.state-change")
        var publisher: Publisher? = null
        try {
            // Create a publisher instance with default settings bound to the topic
            publisher = Publisher.newBuilder(topicName).build()
            val data: ByteString = ByteString.copyFromUtf8(message)
            val pubsubMessage: PubsubMessage = PubsubMessage.newBuilder().setData(data).build()

            // Once published, returns a server-assigned message id (unique within the topic)
            val messageIdFuture: ApiFuture<String> = publisher.publish(pubsubMessage)
            val messageId: String = messageIdFuture.get()
            logger.info("Published message ID: $messageId")
        } finally {
            if (publisher != null) {
                // When finished with the publisher, shutdown to free up resources.
                publisher.shutdown()
                publisher.awaitTermination(1, TimeUnit.MINUTES)
            }
        }
    }
}