diff --git a/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt b/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt
index 0a287a7f7d..6c8279a1e8 100644
--- a/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt
+++ b/core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt
@@ -32,6 +32,7 @@ import net.corda.core.serialization.internal.AttachmentURLStreamHandlerFactory.t
 import net.corda.core.serialization.withWhitelist
 import net.corda.core.utilities.contextLogger
 import net.corda.core.utilities.debug
+import net.corda.core.utilities.loggerFor
 import java.io.IOException
 import java.io.InputStream
 import java.lang.ref.WeakReference
@@ -470,7 +471,18 @@ interface AttachmentsClassLoaderCache {
 @DeleteForDJVM
 class AttachmentsClassLoaderCacheImpl(cacheFactory: NamedCacheFactory) : SingletonSerializeAsToken(), AttachmentsClassLoaderCache {
 
-    private val cache: Cache<AttachmentsClassLoaderKey, SerializationContext> = cacheFactory.buildNamed(Caffeine.newBuilder(), "AttachmentsClassLoader_cache")
+    private val cache: Cache<AttachmentsClassLoaderKey, SerializationContext> = cacheFactory.buildNamed(
+        // Close deserialization classloaders when we evict them
+        // to release any resources they may be holding.
+        @Suppress("TooGenericExceptionCaught")
+        Caffeine.newBuilder().removalListener { key, context, _ ->
+            try {
+                (context?.deserializationClassLoader as? AutoCloseable)?.close()
+            } catch (e: Exception) {
+                loggerFor<AttachmentsClassLoaderCacheImpl>().warn("Error destroying serialization context for $key", e)
+            }
+        }, "AttachmentsClassLoader_cache"
+    )
 
     override fun computeIfAbsent(key: AttachmentsClassLoaderKey, mappingFunction: Function<in AttachmentsClassLoaderKey, out SerializationContext>): SerializationContext {
         return cache.get(key, mappingFunction)  ?: throw NullPointerException("null returned from cache mapping function")
diff --git a/core/src/main/kotlin/net/corda/core/transactions/TransactionBuilder.kt b/core/src/main/kotlin/net/corda/core/transactions/TransactionBuilder.kt
index 71fb6c728b..c05f378223 100644
--- a/core/src/main/kotlin/net/corda/core/transactions/TransactionBuilder.kt
+++ b/core/src/main/kotlin/net/corda/core/transactions/TransactionBuilder.kt
@@ -741,9 +741,11 @@ open class TransactionBuilder(
                     addReferenceState(resolvedStateAndRef.referenced())
                 }
             } else {
-                log.warn("WARNING: You must pass in a ServiceHub reference to TransactionBuilder to resolve " +
-                        "state pointers outside of flows. If you are writing a unit test then pass in a " +
-                        "MockServices instance.")
+                if (nextStatePointer.isResolved) {
+                    log.warn("WARNING: You must pass in a ServiceHub reference to TransactionBuilder to resolve " +
+                            "state pointers outside of flows. If you are writing a unit test then pass in a " +
+                            "MockServices instance.")
+                }
                 return
             }
         }
diff --git a/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt b/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt
index 2f2479c139..3d83201494 100644
--- a/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt
+++ b/node/src/main/kotlin/net/corda/node/internal/AbstractNode.kt
@@ -171,7 +171,6 @@ import org.jolokia.jvmagent.JolokiaServerConfig
 import org.slf4j.Logger
 import rx.Scheduler
 import java.lang.reflect.InvocationTargetException
-import java.net.URLConnection
 import java.sql.Connection
 import java.sql.Savepoint
 import java.time.Clock
@@ -237,7 +236,6 @@ abstract class AbstractNode<S>(val configuration: NodeConfiguration,
         }
 
         quasarExcludePackages(configuration)
-        disableURLConnectionCache()
 
         if (allowHibernateToManageAppSchema && !configuration.devMode) {
             throw ConfigurationException("Hibernate can only be used to manage app schema in development while using dev mode. " +
@@ -424,13 +422,6 @@ abstract class AbstractNode<S>(val configuration: NodeConfiguration,
         }
     }
 
-    private fun disableURLConnectionCache() {
-        object : URLConnection(null) {
-            override fun connect() {
-            }
-        }.defaultUseCaches = false
-    }
-
     private fun quasarExcludePackages(nodeConfiguration: NodeConfiguration) {
         val quasarInstrumentor = Retransform.getInstrumentor()
 
diff --git a/node/src/main/kotlin/net/corda/node/utilities/NodeNamedCache.kt b/node/src/main/kotlin/net/corda/node/utilities/NodeNamedCache.kt
index e43b2ab7ee..9c2e2eaf93 100644
--- a/node/src/main/kotlin/net/corda/node/utilities/NodeNamedCache.kt
+++ b/node/src/main/kotlin/net/corda/node/utilities/NodeNamedCache.kt
@@ -33,7 +33,8 @@ open class DefaultNamedCacheFactory protected constructor(private val metricRegi
     override fun bindWithMetrics(metricRegistry: MetricRegistry): BindableNamedCacheFactory = DefaultNamedCacheFactory(metricRegistry, this.nodeConfiguration)
     override fun bindWithConfig(nodeConfiguration: NodeConfiguration): BindableNamedCacheFactory = DefaultNamedCacheFactory(this.metricRegistry, nodeConfiguration)
 
-    open protected fun <K, V> configuredForNamed(caffeine: Caffeine<K, V>, name: String): Caffeine<K, V> {
+    @Suppress("ComplexMethod")
+    protected open fun <K, V> configuredForNamed(caffeine: Caffeine<K, V>, name: String): Caffeine<K, V> {
         return with(nodeConfiguration!!) {
             when {
                 name.startsWith("RPCSecurityManagerShiroCache_") -> with(security?.authService?.options?.cache!!) { caffeine.maximumSize(maxEntries).expireAfterWrite(expireAfterSecs, TimeUnit.SECONDS) }
@@ -84,7 +85,7 @@ open class DefaultNamedCacheFactory protected constructor(private val metricRegi
         return configuredForNamed(caffeine, name).build<K, V>(loader)
     }
 
-    open protected val defaultCacheSize = 1024L
+    protected open val defaultCacheSize = 1024L
     private val defaultAttachmentsClassLoaderCacheSize = defaultCacheSize / CACHE_SIZE_DENOMINATOR
 }
-private const val CACHE_SIZE_DENOMINATOR = 4L
\ No newline at end of file
+private const val CACHE_SIZE_DENOMINATOR = 4L