[CORDA-2390] - Add whitelists and custom serializers from cordapps to serialization … (#4551)

* Add whitelists and custom serializers from cordapps to serialization context

* Remove changes in TransactionBuilder, add caching

* Add whitelists and custom serializers from cordapps to serialization context

* Remove changes in TransactionBuilder, add caching

* Address comments

* Increase node memory for SIMM integration test

* Cache only serialization context

* Increase integ test timeout

* Fix API breakage

* Increase max heap size for web server integ test

* Move classloading utils from separate module to core.internal

* Adjust heap size for more integ tests

* Increase time window for IRS demo transactions

* Fix determinator

* Add parameter in core-deterministic

* Stub out class-loading method for DJVM

client/rpc/src/main/kotlin/net/corda/client/rpc/CordaRPCClient.kt

@@ -3,12 +3,15 @@ package net.corda.client.rpc
 import com.github.benmanes.caffeine.cache.Caffeine
 import net.corda.client.rpc.internal.RPCClient
 import net.corda.client.rpc.internal.serialization.amqp.AMQPClientSerializationScheme
+import net.corda.core.internal.loadClassesImplementing
 import net.corda.core.context.Actor
 import net.corda.core.context.Trace
 import net.corda.core.identity.CordaX500Name
 import net.corda.core.internal.PLATFORM_VERSION
 import net.corda.core.messaging.ClientRpcSslOptions
 import net.corda.core.messaging.CordaRPCOps
+import net.corda.core.serialization.SerializationCustomSerializer
+import net.corda.core.serialization.SerializationWhitelist
 import net.corda.core.serialization.internal.effectiveSerializationEnv
 import net.corda.core.utilities.NetworkHostAndPort
 import net.corda.core.utilities.days
@@ -19,6 +22,7 @@ import net.corda.serialization.internal.AMQP_RPC_CLIENT_CONTEXT
 import net.corda.serialization.internal.amqp.SerializationFactoryCacheKey
 import net.corda.serialization.internal.amqp.SerializerFactory
 import java.time.Duration
+import java.util.ServiceLoader
 
 /**
  * This class is essentially just a wrapper for an RPCConnection<CordaRPCOps> and can be treated identically.
@@ -240,6 +244,7 @@ open class CordaRPCClientConfiguration @JvmOverloads constructor(
  * @param configuration An optional configuration used to tweak client behaviour.
  * @param sslConfiguration An optional [ClientRpcSslOptions] used to enable secure communication with the server.
  * @param haAddressPool A list of [NetworkHostAndPort] representing the addresses of servers in HA mode.
+ * @param classLoader a classloader, which will be used (if provided) to discover available [SerializationCustomSerializer]s and [SerializationWhitelist]s
  * The client will attempt to connect to a live server by trying each address in the list. If the servers are not in
  * HA mode, the client will round-robin from the beginning of the list and try all servers.
  */
@@ -252,8 +257,9 @@ class CordaRPCClient private constructor(
 ) {
     @JvmOverloads
     constructor(hostAndPort: NetworkHostAndPort,
-                configuration: CordaRPCClientConfiguration = CordaRPCClientConfiguration.DEFAULT)
+                configuration: CordaRPCClientConfiguration = CordaRPCClientConfiguration.DEFAULT,
-            : this(hostAndPort, configuration, null)
+                classLoader: ClassLoader? = null)
+            : this(hostAndPort, configuration, null, classLoader = classLoader)
 
     /**
      * @param haAddressPool A list of [NetworkHostAndPort] representing the addresses of servers in HA mode.
@@ -287,7 +293,7 @@ class CordaRPCClient private constructor(
                 sslConfiguration: ClientRpcSslOptions? = null,
                 classLoader: ClassLoader? = null
         ): CordaRPCClient {
-            return CordaRPCClient(hostAndPort, configuration, sslConfiguration, classLoader)
+            return CordaRPCClient(hostAndPort, configuration, sslConfiguration, classLoader = classLoader)
         }
     }
 
@@ -296,7 +302,14 @@ class CordaRPCClient private constructor(
             effectiveSerializationEnv
         } catch (e: IllegalStateException) {
             try {
-                AMQPClientSerializationScheme.initialiseSerialization(classLoader, Caffeine.newBuilder().maximumSize(128).build<SerializationFactoryCacheKey, SerializerFactory>().asMap())
+                // If the client has provided a classloader, the associated classpath is checked for available custom serializers and serialization whitelists.
+                if (classLoader != null) {
+                    val customSerializers = loadClassesImplementing(classLoader, SerializationCustomSerializer::class.java)
+                    val serializationWhitelists = ServiceLoader.load(SerializationWhitelist::class.java, classLoader).toSet()
+                    AMQPClientSerializationScheme.initialiseSerialization(classLoader, customSerializers, serializationWhitelists, Caffeine.newBuilder().maximumSize(128).build<SerializationFactoryCacheKey, SerializerFactory>().asMap())
+                } else {
+                    AMQPClientSerializationScheme.initialiseSerialization(classLoader, serializerFactoriesForContexts =  Caffeine.newBuilder().maximumSize(128).build<SerializationFactoryCacheKey, SerializerFactory>().asMap())
+                }
             } catch (e: IllegalStateException) {
                 // Race e.g. two of these constructed in parallel, ignore.
             }

client/rpc/src/main/kotlin/net/corda/client/rpc/internal/serialization/amqp/AMQPClientSerializationScheme.kt

@@ -5,6 +5,7 @@ import net.corda.core.internal.toSynchronised
 import net.corda.core.serialization.SerializationContext
 import net.corda.core.serialization.SerializationContext.UseCase
 import net.corda.core.serialization.SerializationCustomSerializer
+import net.corda.core.serialization.SerializationWhitelist
 import net.corda.core.serialization.internal.SerializationEnvironment
 import net.corda.core.serialization.internal.nodeSerializationEnv
 import net.corda.serialization.internal.*
@@ -17,24 +18,25 @@ import net.corda.serialization.internal.amqp.custom.RxNotificationSerializer
  */
 class AMQPClientSerializationScheme(
         cordappCustomSerializers: Set<SerializationCustomSerializer<*,*>>,
+        cordappSerializationWhitelists: Set<SerializationWhitelist>,
         serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>
-    ) : AbstractAMQPSerializationScheme(cordappCustomSerializers, serializerFactoriesForContexts) {
+    ) : AbstractAMQPSerializationScheme(cordappCustomSerializers, cordappSerializationWhitelists, serializerFactoriesForContexts) {
-    constructor(cordapps: List<Cordapp>) : this(cordapps.customSerializers, AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
+    constructor(cordapps: List<Cordapp>) : this(cordapps.customSerializers, cordapps.serializationWhitelists, AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
-    constructor(cordapps: List<Cordapp>, serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>) : this(cordapps.customSerializers, serializerFactoriesForContexts)
+    constructor(cordapps: List<Cordapp>, serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>) : this(cordapps.customSerializers, cordapps.serializationWhitelists, serializerFactoriesForContexts)
 
     @Suppress("UNUSED")
-    constructor() : this(emptySet(), AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
+    constructor() : this(emptySet(), emptySet(), AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
 
     companion object {
         /** Call from main only. */
-        fun initialiseSerialization(classLoader: ClassLoader? = null, serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory> = AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised()) {
+        fun initialiseSerialization(classLoader: ClassLoader? = null, customSerializers: Set<SerializationCustomSerializer<*, *>> = emptySet(), serializationWhitelists: Set<SerializationWhitelist> = emptySet(), serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory> = AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised()) {
-            nodeSerializationEnv = createSerializationEnv(classLoader, serializerFactoriesForContexts)
+            nodeSerializationEnv = createSerializationEnv(classLoader, customSerializers, serializationWhitelists, serializerFactoriesForContexts)
         }
 
-        fun createSerializationEnv(classLoader: ClassLoader? = null, serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory> = AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised()): SerializationEnvironment {
+        fun createSerializationEnv(classLoader: ClassLoader? = null, customSerializers: Set<SerializationCustomSerializer<*, *>> = emptySet(), serializationWhitelists: Set<SerializationWhitelist> = emptySet(), serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory> = AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised()): SerializationEnvironment {
             return SerializationEnvironment.with(
                     SerializationFactoryImpl().apply {
-                        registerScheme(AMQPClientSerializationScheme(emptyList(), serializerFactoriesForContexts))
+                        registerScheme(AMQPClientSerializationScheme(customSerializers, serializationWhitelists, serializerFactoriesForContexts))
                     },
                     storageContext = AMQP_STORAGE_CONTEXT,
                     p2pContext = if (classLoader != null) AMQP_P2P_CONTEXT.withClassLoader(classLoader) else AMQP_P2P_CONTEXT,

core-deterministic/testing/src/test/kotlin/net/corda/core/internal/ClassLoadingUtils.kt

@@ -0,0 +1,8 @@
+package net.corda.core.internal
+
+/**
+ * Stubbing out non-deterministic method.
+ */
+fun <T: Any> loadClassesImplementing(classloader: ClassLoader, clazz: Class<T>): Set<T> {
+    return emptySet()
+}

core-deterministic/testing/verifier/src/main/kotlin/net/corda/deterministic/verifier/LocalSerializationRule.kt

@@ -4,6 +4,7 @@ import net.corda.core.serialization.ClassWhitelist
 import net.corda.core.serialization.SerializationContext
 import net.corda.core.serialization.SerializationContext.UseCase.P2P
 import net.corda.core.serialization.SerializationCustomSerializer
+import net.corda.core.serialization.SerializationWhitelist
 import net.corda.core.serialization.internal.SerializationEnvironment
 import net.corda.core.serialization.internal._contextSerializationEnv
 import net.corda.serialization.internal.*
@@ -57,15 +58,16 @@ class LocalSerializationRule(private val label: String) : TestRule {
 
     private fun createTestSerializationEnv(): SerializationEnvironment {
         val factory = SerializationFactoryImpl(mutableMapOf()).apply {
-            registerScheme(AMQPSerializationScheme(emptySet(), AccessOrderLinkedHashMap(128)))
+            registerScheme(AMQPSerializationScheme(emptySet(), emptySet(), AccessOrderLinkedHashMap(128)))
         }
         return SerializationEnvironment.with(factory, AMQP_P2P_CONTEXT)
     }
 
     private class AMQPSerializationScheme(
             cordappCustomSerializers: Set<SerializationCustomSerializer<*, *>>,
+            cordappSerializationWhitelists: Set<SerializationWhitelist>,
             serializerFactoriesForContexts: AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>
-    ) : AbstractAMQPSerializationScheme(cordappCustomSerializers, serializerFactoriesForContexts) {
+    ) : AbstractAMQPSerializationScheme(cordappCustomSerializers, cordappSerializationWhitelists, serializerFactoriesForContexts) {
         override fun rpcServerSerializerFactory(context: SerializationContext): SerializerFactory {
             throw UnsupportedOperationException()
         }

core/build.gradle

@@ -111,6 +111,8 @@ dependencies {
 
     // required to use @Type annotation
     compile "org.hibernate:hibernate-core:$hibernate_version"
+
+    compile group: "io.github.classgraph", name: "classgraph", version: class_graph_version
 }
 
 // TODO Consider moving it to quasar-utils in the future (introduced with PR-1388)

core/src/main/kotlin/net/corda/core/internal/ClassLoadingUtils.kt

@@ -0,0 +1,31 @@
+package net.corda.core.internal
+
+import io.github.classgraph.ClassGraph
+import net.corda.core.CordaInternal
+import net.corda.core.DeleteForDJVM
+import net.corda.core.StubOutForDJVM
+import kotlin.reflect.full.createInstance
+
+/**
+ * Creates instances of all the classes in the classpath of the provided classloader, which implement the interface of the provided class.
+ * @param classloader the classloader, which will be searched for the classes.
+ * @param clazz the class of the interface, which the classes - to be returned - must implement.
+ *
+ * @return instances of the identified classes.
+ * @throws IllegalArgumentException if the classes found do not have proper constructors.
+ *
+ * Note: In order to be instantiated, the associated classes must:
+ * - be non-abstract
+ * - either be a Kotlin object or have a constructor with no parameters (or only optional ones)
+ */
+@StubOutForDJVM
+fun <T: Any> loadClassesImplementing(classloader: ClassLoader, clazz: Class<T>): Set<T> {
+    return ClassGraph().addClassLoader(classloader)
+            .enableAllInfo()
+            .scan()
+            .getClassesImplementing(clazz.name)
+            .filterNot { it.isAbstract }
+            .mapNotNull { classloader.loadClass(it.name).asSubclass(clazz) }
+            .map { it.kotlin.objectInstance ?: it.kotlin.createInstance() }
+            .toSet()
+}

core/src/main/kotlin/net/corda/core/internal/CordaUtils.kt

@@ -19,12 +19,16 @@ import net.corda.core.node.services.vault.Builder
 import net.corda.core.node.services.vault.Sort
 import net.corda.core.serialization.CordaSerializable
 import net.corda.core.serialization.SerializationContext
+import net.corda.core.serialization.internal.AttachmentsClassLoaderBuilder
 import net.corda.core.transactions.LedgerTransaction
 import net.corda.core.transactions.SignedTransaction
 import net.corda.core.transactions.TransactionBuilder
 import net.corda.core.transactions.WireTransaction
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 import org.slf4j.MDC
 import java.security.PublicKey
+import java.util.jar.JarEntry
 import java.util.jar.JarInputStream
 
 // *Internal* Corda-specific utilities.

core/src/main/kotlin/net/corda/core/serialization/SerializationAPI.kt

@@ -1,6 +1,7 @@
 @file:KeepForDJVM
 package net.corda.core.serialization
 
+import co.paralleluniverse.io.serialization.Serialization
 import net.corda.core.CordaInternal
 import net.corda.core.DeleteForDJVM
 import net.corda.core.DoNotImplement
@@ -160,6 +161,10 @@ interface SerializationContext {
      * The use case we are serializing or deserializing for.  See [UseCase].
      */
     val useCase: UseCase
+    /**
+     * Additional custom serializers that will be made available during (de)serialization.
+     */
+    val customSerializers: Set<SerializationCustomSerializer<*, *>>
 
     /**
      * Helper method to return a new context based on this context with the property added.
@@ -200,6 +205,11 @@ interface SerializationContext {
      */
     fun withWhitelisted(clazz: Class<*>): SerializationContext
 
+    /**
+     * Helper method to return a new context based on this context with the given serializers added.
+     */
+    fun withCustomSerializers(serializers: Set<SerializationCustomSerializer<*, *>>): SerializationContext
+
     /**
      * Helper method to return a new context based on this context but with serialization using the format this header sequence represents.
      */
@@ -335,3 +345,15 @@ interface ClassWhitelist {
 interface EncodingWhitelist {
     fun acceptEncoding(encoding: SerializationEncoding): Boolean
 }
+
+/**
+ * Helper method to return a new context based on this context with the given list of classes specifically whitelisted.
+ */
+fun SerializationContext.withWhitelist(classes: List<Class<*>>): SerializationContext {
+    var currentContext = this
+    classes.forEach {
+        clazz -> currentContext = currentContext.withWhitelisted(clazz)
+    }
+
+    return currentContext
+}

core/src/main/kotlin/net/corda/core/serialization/internal/AttachmentsClassLoader.kt

@@ -2,6 +2,7 @@ package net.corda.core.serialization.internal
 
 import net.corda.core.CordaException
 import net.corda.core.KeepForDJVM
+import net.corda.core.internal.loadClassesImplementing
 import net.corda.core.contracts.Attachment
 import net.corda.core.contracts.ContractAttachment
 import net.corda.core.contracts.TransactionVerificationException.OverlappingAttachmentsException
@@ -10,7 +11,11 @@ import net.corda.core.crypto.sha256
 import net.corda.core.internal.*
 import net.corda.core.internal.cordapp.targetPlatformVersion
 import net.corda.core.serialization.CordaSerializable
+import net.corda.core.serialization.MissingAttachmentsException
+import net.corda.core.serialization.SerializationCustomSerializer
 import net.corda.core.serialization.SerializationFactory
+import net.corda.core.serialization.SerializationWhitelist
+import net.corda.core.serialization.*
 import net.corda.core.serialization.internal.AttachmentURLStreamHandlerFactory.toUrl
 import net.corda.core.utilities.contextLogger
 import net.corda.core.utilities.debug
@@ -18,6 +23,7 @@ import java.io.ByteArrayOutputStream
 import java.io.IOException
 import java.io.InputStream
 import java.net.*
+import java.util.*
 
 /**
  * A custom ClassLoader that knows how to load classes from a set of attachments. The attachments themselves only
@@ -174,34 +180,38 @@ class AttachmentsClassLoader(attachments: List<Attachment>, parent: ClassLoader
 }
 
 /**
- * This is just a factory that provides a cache to avoid constructing expensive [AttachmentsClassLoader]s.
+ * This is just a factory that provides caches to optimise expensive construction/loading of classloaders, serializers, whitelisted classes.
  */
 @VisibleForTesting
 internal object AttachmentsClassLoaderBuilder {
 
-    private const val ATTACHMENT_CLASSLOADER_CACHE_SIZE = 1000
+    private const val CACHE_SIZE = 1000
 
     // This runs in the DJVM so it can't use caffeine.
-    private val cache: MutableMap<List<SecureHash>, AttachmentsClassLoader> = createSimpleCache<List<SecureHash>, AttachmentsClassLoader>(ATTACHMENT_CLASSLOADER_CACHE_SIZE)
+    private val cache: MutableMap<Set<SecureHash>, SerializationContext> = createSimpleCache(CACHE_SIZE)
-            .toSynchronised()
-
-    fun build(attachments: List<Attachment>): AttachmentsClassLoader {
-        return cache.computeIfAbsent(attachments.map { it.id }.sorted()) {
-            AttachmentsClassLoader(attachments)
-        }
-    }
 
     fun <T> withAttachmentsClassloaderContext(attachments: List<Attachment>, block: (ClassLoader) -> T): T {
+        val attachmentIds = attachments.map { it.id }.toSet()
 
-        // Create classloader from the attachments.
+        val serializationContext = cache.computeIfAbsent(attachmentIds) {
-        val transactionClassLoader = AttachmentsClassLoaderBuilder.build(attachments)
+            // Create classloader and load serializers, whitelisted classes
+            val transactionClassLoader = AttachmentsClassLoader(attachments)
+            val serializers = loadClassesImplementing(transactionClassLoader, SerializationCustomSerializer::class.java)
+            val whitelistedClasses = ServiceLoader.load(SerializationWhitelist::class.java, transactionClassLoader)
+                    .flatMap { it.whitelist }
+                    .toList()
 
             // Create a new serializationContext for the current Transaction.
-        val transactionSerializationContext = SerializationFactory.defaultFactory.defaultContext.withPreventDataLoss().withClassLoader(transactionClassLoader)
+            SerializationFactory.defaultFactory.defaultContext
+                    .withPreventDataLoss()
+                    .withClassLoader(transactionClassLoader)
+                    .withWhitelist(whitelistedClasses)
+                    .withCustomSerializers(serializers)
+        }
 
         // Deserialize all relevant classes in the transaction classloader.
-        return SerializationFactory.defaultFactory.withCurrentContext(transactionSerializationContext) {
+        return SerializationFactory.defaultFactory.withCurrentContext(serializationContext) {
-            block(transactionClassLoader)
+            block(serializationContext.deserializationClassLoader)
         }
     }
 }

core/src/test/kotlin/net/corda/core/internal/ClassLoadingUtilsTest.kt

@@ -0,0 +1,34 @@
+package net.corda.core.internal
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.Test
+import java.lang.IllegalArgumentException
+
+class ClassLoadingUtilsTest {
+
+    interface BaseInterface {}
+
+    interface BaseInterface2 {}
+
+    class ConcreteClassWithEmptyConstructor: BaseInterface {}
+
+    abstract class AbstractClass: BaseInterface
+
+    class ConcreteClassWithNonEmptyConstructor(private val someData: Int): BaseInterface2 {}
+
+    @Test
+    fun predicateClassAreLoadedSuccessfully() {
+        val classes = loadClassesImplementing(BaseInterface::class.java.classLoader, BaseInterface::class.java)
+
+        val classNames = classes.map { it.javaClass.name }
+
+        assertThat(classNames).contains(ConcreteClassWithEmptyConstructor::class.java.name)
+        assertThat(classNames).doesNotContain(AbstractClass::class.java.name)
+    }
+
+    @Test(expected = IllegalArgumentException::class)
+    fun throwsExceptionWhenClassDoesNotContainProperConstructors() {
+        val classes = loadClassesImplementing(BaseInterface::class.java.classLoader, BaseInterface2::class.java)
+    }
+
+}

finance/workflows/src/main/kotlin/net/corda/finance/flows/TwoPartyDealFlow.kt

@@ -190,7 +190,7 @@ object TwoPartyDealFlow {
 
             // We set the transaction's time-window: it may be that none of the contracts need this!
             // But it can't hurt to have one.
-            ptx.setTimeWindow(serviceHub.clock.instant(), 30.seconds)
+            ptx.setTimeWindow(serviceHub.clock.instant(), 60.seconds)
             return Triple(ptx, arrayListOf(deal.participants.single { it is Party && serviceHub.myInfo.isLegalIdentity(it) }.owningKey), emptyList())
         }
     }

node/src/integration-test/kotlin/net/corda/node/flows/FlowCheckpointVersionNodeStartupCheckTest.kt

@@ -47,7 +47,7 @@ class FlowCheckpointVersionNodeStartupCheckTest {
             val result = if (page.snapshot.states.isNotEmpty()) {
                 page.snapshot.states.first()
             } else {
-                val r = page.updates.timeout(5, TimeUnit.SECONDS).take(1).toBlocking().single()
+                val r = page.updates.timeout(10, TimeUnit.SECONDS).take(1).toBlocking().single()
                 if (r.consumed.isNotEmpty()) r.consumed.first() else r.produced.first()
             }
             assertNotNull(result)

node/src/main/kotlin/net/corda/node/serialization/amqp/AMQPServerSerializationScheme.kt

@@ -4,6 +4,7 @@ import net.corda.core.cordapp.Cordapp
 import net.corda.core.internal.toSynchronised
 import net.corda.core.serialization.SerializationContext
 import net.corda.core.serialization.SerializationCustomSerializer
+import net.corda.core.serialization.SerializationWhitelist
 import net.corda.serialization.internal.CordaSerializationMagic
 import net.corda.serialization.internal.amqp.*
 import net.corda.serialization.internal.amqp.custom.RxNotificationSerializer
@@ -14,12 +15,13 @@ import net.corda.serialization.internal.amqp.custom.RxNotificationSerializer
  */
 class AMQPServerSerializationScheme(
         cordappCustomSerializers: Set<SerializationCustomSerializer<*, *>>,
+        cordappSerializationWhitelists: Set<SerializationWhitelist>,
         serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>
-) : AbstractAMQPSerializationScheme(cordappCustomSerializers, serializerFactoriesForContexts) {
+) : AbstractAMQPSerializationScheme(cordappCustomSerializers, cordappSerializationWhitelists, serializerFactoriesForContexts) {
-    constructor(cordapps: List<Cordapp>) : this(cordapps.customSerializers, AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
+    constructor(cordapps: List<Cordapp>) : this(cordapps.customSerializers, cordapps.serializationWhitelists, AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
-    constructor(cordapps: List<Cordapp>, serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>) : this(cordapps.customSerializers, serializerFactoriesForContexts)
+    constructor(cordapps: List<Cordapp>, serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>) : this(cordapps.customSerializers, cordapps.serializationWhitelists, serializerFactoriesForContexts)
 
-    constructor() : this(emptySet(), AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised() )
+    constructor() : this(emptySet(), emptySet(), AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised() )
 
     override fun rpcClientSerializerFactory(context: SerializationContext): SerializerFactory {
         throw UnsupportedOperationException()

node/src/test/kotlin/net/corda/node/internal/serialization/RoundTripObservableSerializerTests.kt

@@ -59,7 +59,7 @@ class RoundTripObservableSerializerTests {
     @Test
     fun roundTripTest1() {
         val serializationScheme = AMQPRoundTripRPCSerializationScheme(
-                serializationContext, emptySet(), AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
+                serializationContext, emptySet(), emptySet(), AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
 
         // Fake up a message ID, needs to be used on both "sides". The server setting it in the subscriptionMap,
         // the client as a property of the deserializer which, in the actual RPC client, is pulled off of

node/src/test/kotlin/net/corda/node/internal/serialization/testutils/AMQPTestSerialiationScheme.kt

@@ -4,6 +4,7 @@ import net.corda.client.rpc.internal.serialization.amqp.RpcClientObservableDeSer
 import net.corda.core.context.Trace
 import net.corda.core.serialization.SerializationContext
 import net.corda.core.serialization.SerializationCustomSerializer
+import net.corda.core.serialization.SerializationWhitelist
 import net.corda.node.serialization.amqp.RpcServerObservableSerializer
 import net.corda.nodeapi.RPCApi
 import net.corda.serialization.internal.CordaSerializationMagic
@@ -20,9 +21,10 @@ import net.corda.client.rpc.internal.ObservableContext as ClientObservableContex
 class AMQPRoundTripRPCSerializationScheme(
         private val serializationContext: SerializationContext,
         cordappCustomSerializers: Set<SerializationCustomSerializer<*, *>>,
+        cordappSerializationWhitelists: Set<SerializationWhitelist>,
         serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>)
     : AbstractAMQPSerializationScheme(
-        cordappCustomSerializers, serializerFactoriesForContexts
+        cordappCustomSerializers, cordappSerializationWhitelists, serializerFactoriesForContexts
 ) {
     override fun rpcClientSerializerFactory(context: SerializationContext): SerializerFactory {
         return SerializerFactoryBuilder.build(AllWhitelist, javaClass.classLoader).apply {

samples/attachment-demo/src/integration-test/kotlin/net/corda/attachmentdemo/AttachmentDemoTest.kt

@@ -23,7 +23,7 @@ class AttachmentDemoTest {
                     startNode(providedName = DUMMY_BANK_A_NAME, rpcUsers = demoUser, maximumHeapSize = "1g"),
                     startNode(providedName = DUMMY_BANK_B_NAME, rpcUsers = demoUser, maximumHeapSize = "1g")
             ).map { it.getOrThrow() }
-            val webserverHandle = startWebserver(nodeB).getOrThrow()
+            val webserverHandle = startWebserver(nodeB, "1g").getOrThrow()
 
             val senderThread = supplyAsync {
                 CordaRPCClient(nodeA.rpcAddress).start(demoUser[0].username, demoUser[0].password).use {

samples/irs-demo/cordapp/src/main/kotlin/net/corda/irs/flows/FixingFlow.kt

@@ -63,7 +63,7 @@ object FixingFlow {
 
                     // We set the transaction's time-window: it may be that none of the contracts need this!
                     // But it can't hurt to have one.
-                    ptx.setTimeWindow(serviceHub.clock.instant(), 30.seconds)
+                    ptx.setTimeWindow(serviceHub.clock.instant(), 60.seconds)
                 }
 
                 @Suspendable

samples/simm-valuation-demo/build.gradle

@@ -33,6 +33,7 @@ dependencies {
     cordapp project(':finance:workflows')
     cordapp project(path: ':samples:simm-valuation-demo:contracts-states', configuration: 'shrinkArtifacts')
     cordapp project(':samples:simm-valuation-demo:flows')
+    cordapp project(':confidential-identities')
 
     // Corda integration dependencies
     cordaRuntime project(path: ":node:capsule", configuration: 'runtimeArtifacts')
@@ -71,6 +72,7 @@ task deployNodes(type: net.corda.plugins.Cordform, dependsOn: ['jar', nodeTask,
         cordapp project(':finance:workflows')
         cordapp project(':samples:simm-valuation-demo:contracts-states')
         cordapp project(':samples:simm-valuation-demo:flows')
+        cordapp project(':confidential-identities')
         rpcUsers = [['username': "default", 'password': "default", 'permissions': [ 'ALL' ]]]
     }
     node {

samples/simm-valuation-demo/contracts-states/src/main/kotlin/net/corda/vega/plugin/customserializers/CurrencySerializer.kt

@@ -0,0 +1,30 @@
+package net.corda.vega.plugin.customserializers
+
+import com.opengamma.strata.basics.currency.Currency
+import net.corda.core.serialization.SerializationCustomSerializer
+
+@Suppress("UNUSED")
+class CurrencySerializer : SerializationCustomSerializer<Currency, CurrencySerializer.Proxy> {
+    data class Proxy(val currency: String)
+
+    override fun fromProxy(proxy: Proxy): Currency {
+        return withCurrentClassLoader { Currency.parse(proxy.currency) }
+    }
+    override fun toProxy(obj: Currency) = Proxy(obj.toString())
+
+    /**
+     * The initialization of [Currency] uses the classpath to identify needed resources.
+     * However, it gives priority to the classloader in the thread context over the one this class was loaded with.
+     * See: [com.opengamma.strata.collect.io.ResourceLocator.classLoader]
+     *
+     * This is the reason we temporarily override the class loader in the thread context here, with the classloader of this
+     * class, which is guaranteed to contain everything in the 3rd party library's classpath.
+     */
+    private fun withCurrentClassLoader(serializationFunction: () -> Currency): Currency {
+        val threadClassLoader = Thread.currentThread().contextClassLoader
+        Thread.currentThread().contextClassLoader = this.javaClass.classLoader
+        val result =serializationFunction()
+        Thread.currentThread().contextClassLoader = threadClassLoader
+        return result
+    }
+}

samples/simm-valuation-demo/flows/src/main/kotlin/net/corda/vega/plugin/SimmFlowsPluginRegistry.kt

@@ -1,40 +0,0 @@
-package net.corda.vega.plugin
-
-import com.google.common.collect.Ordering
-import com.opengamma.strata.basics.currency.Currency
-import com.opengamma.strata.basics.currency.CurrencyAmount
-import com.opengamma.strata.basics.currency.MultiCurrencyAmount
-import com.opengamma.strata.basics.date.Tenor
-import com.opengamma.strata.collect.array.DoubleArray
-import com.opengamma.strata.market.curve.CurveName
-import com.opengamma.strata.market.param.CurrencyParameterSensitivities
-import com.opengamma.strata.market.param.CurrencyParameterSensitivity
-import com.opengamma.strata.market.param.TenorDateParameterMetadata
-import com.opengamma.strata.market.param.ParameterMetadata
-import net.corda.core.serialization.SerializationWhitelist
-import net.corda.vega.analytics.CordaMarketData
-import net.corda.vega.analytics.InitialMarginTriple
-
-/**
- * [SimmService] is the object that makes available the flows and services for the Simm agreement / evaluation flow.
- * It is loaded via discovery - see [SerializationWhitelist].
- * It is also the object that enables a human usable web service for demo purpose
- * It is loaded via discovery see [WebServerPluginRegistry].
- */
-class SimmFlowsPluginRegistry : SerializationWhitelist {
-    override val whitelist = listOf(
-//            MultiCurrencyAmount::class.java,
-//            Ordering.natural<Comparable<Any>>().javaClass,
-//            CurrencyAmount::class.java,
-//            Currency::class.java,
-//            InitialMarginTriple::class.java,
-//            CordaMarketData::class.java,
-//            CurrencyParameterSensitivities::class.java,
-//            CurrencyParameterSensitivity::class.java,
-            DoubleArray::class.java
-//            CurveName::class.java,
-//            TenorDateParameterMetadata::class.java,
-//            Tenor::class.java,
-//            ParameterMetadata::class.java
-    )
-}

samples/simm-valuation-demo/flows/src/main/kotlin/net/corda/vega/plugin/customserializers/CurrencySerializer.kt

@@ -1,12 +0,0 @@
-package net.corda.vega.plugin.customserializers
-
-import com.opengamma.strata.basics.currency.Currency
-import net.corda.core.serialization.SerializationCustomSerializer
-
-@Suppress("UNUSED")
-class CurrencySerializer : SerializationCustomSerializer<Currency, CurrencySerializer.Proxy> {
-    data class Proxy(val currency: String)
-
-    override fun fromProxy(proxy: Proxy): Currency = Currency.parse(proxy.currency)
-    override fun toProxy(obj: Currency) = Proxy(obj.toString())
-}

samples/simm-valuation-demo/flows/src/main/resources/META-INF/services/net.corda.core.serialization.SerializationWhitelist

@@ -1 +0,0 @@
-net.corda.vega.plugin.SimmFlowsPluginRegistry

samples/simm-valuation-demo/src/integration-test/kotlin/net/corda/vega/SimmValuationTest.kt

@@ -9,9 +9,11 @@ import net.corda.serialization.internal.amqp.AbstractAMQPSerializationScheme
 import net.corda.testing.common.internal.ProjectStructure.projectRootDir
 import net.corda.testing.core.DUMMY_BANK_A_NAME
 import net.corda.testing.core.DUMMY_BANK_B_NAME
+import net.corda.testing.core.DUMMY_NOTARY_NAME
 import net.corda.testing.driver.DriverParameters
 import net.corda.testing.driver.driver
 import net.corda.testing.http.HttpApi
+import net.corda.testing.node.NotarySpec
 import net.corda.testing.node.internal.FINANCE_CORDAPPS
 import net.corda.testing.node.internal.findCordapp
 import net.corda.vega.api.PortfolioApi
@@ -51,14 +53,15 @@ class SimmValuationTest {
         val logConfigFile = projectRootDir / "samples" / "simm-valuation-demo" / "src" / "main" / "resources" / "log4j2.xml"
         assertThat(logConfigFile).isRegularFile()
         driver(DriverParameters(isDebug = true,
-                cordappsForAllNodes = listOf(findCordapp("net.corda.vega.flows"), findCordapp("net.corda.vega.contracts")) + FINANCE_CORDAPPS,
+                cordappsForAllNodes = listOf(findCordapp("net.corda.vega.flows"), findCordapp("net.corda.vega.contracts"), findCordapp("net.corda.confidential")) + FINANCE_CORDAPPS,
-                systemProperties = mapOf("log4j.configurationFile" to logConfigFile.toString()))
+                systemProperties = mapOf("log4j.configurationFile" to logConfigFile.toString()),
+                notarySpecs = listOf(NotarySpec(DUMMY_NOTARY_NAME, maximumHeapSize = "1g")))
         ) {
-            val nodeAFuture = startNode(providedName = nodeALegalName)
+            val nodeAFuture = startNode(providedName = nodeALegalName, maximumHeapSize = "1g")
-            val nodeBFuture = startNode(providedName = nodeBLegalName)
+            val nodeBFuture = startNode(providedName = nodeBLegalName, maximumHeapSize = "1g")
             val (nodeA, nodeB) = listOf(nodeAFuture, nodeBFuture).map { it.getOrThrow() }
-            val nodeAWebServerFuture = startWebserver(nodeA)
+            val nodeAWebServerFuture = startWebserver(nodeA, "1g")
-            val nodeBWebServerFuture = startWebserver(nodeB)
+            val nodeBWebServerFuture = startWebserver(nodeB, "1g")
             val nodeAApi = HttpApi.fromHostAndPort(nodeAWebServerFuture.getOrThrow().listenAddress, "api/simmvaluationdemo")
             val nodeBApi = HttpApi.fromHostAndPort(nodeBWebServerFuture.getOrThrow().listenAddress, "api/simmvaluationdemo")
             val nodeBParty = getPartyWithName(nodeAApi, nodeBLegalName)
@@ -68,10 +71,9 @@ class SimmValuationTest {
             assertTradeExists(nodeBApi, nodeAParty, testTradeId)
             assertTradeExists(nodeAApi, nodeBParty, testTradeId)
 
-            // TODO Dimos - uncomment this on the CORDA-2390 branch to prove that the fix works.
+            runValuationsBetween(nodeAApi, nodeBParty)
-//            runValuationsBetween(nodeAApi, nodeBParty)
+            assertValuationExists(nodeBApi, nodeAParty)
-//            assertValuationExists(nodeBApi, nodeAParty)
+            assertValuationExists(nodeAApi, nodeBParty)
-//            assertValuationExists(nodeAApi, nodeBParty)
         }
     }
 

samples/trader-demo/src/integration-test/kotlin/net/corda/traderdemo/TraderDemoTest.kt

@@ -9,14 +9,12 @@ import net.corda.finance.flows.CashIssueFlow
 import net.corda.finance.flows.CashPaymentFlow
 import net.corda.node.services.Permissions.Companion.all
 import net.corda.node.services.Permissions.Companion.startFlow
-import net.corda.testing.core.BOC_NAME
+import net.corda.testing.core.*
-import net.corda.testing.core.DUMMY_BANK_A_NAME
-import net.corda.testing.core.DUMMY_BANK_B_NAME
-import net.corda.testing.core.singleIdentity
 import net.corda.testing.driver.DriverParameters
 import net.corda.testing.driver.InProcess
 import net.corda.testing.driver.OutOfProcess
 import net.corda.testing.driver.driver
+import net.corda.testing.node.NotarySpec
 import net.corda.testing.node.TestCordapp
 import net.corda.testing.node.User
 import net.corda.testing.node.internal.FINANCE_CORDAPPS
@@ -39,12 +37,13 @@ class TraderDemoTest {
         driver(DriverParameters(
                 startNodesInProcess = true,
                 inMemoryDB = false,
-                cordappsForAllNodes = FINANCE_CORDAPPS + TestCordapp.findCordapp("net.corda.traderdemo")
+                cordappsForAllNodes = FINANCE_CORDAPPS + TestCordapp.findCordapp("net.corda.traderdemo"),
+                notarySpecs = listOf(NotarySpec(DUMMY_NOTARY_NAME, maximumHeapSize = "1g"))
         )) {
             val (nodeA, nodeB, bankNode) = listOf(
-                    startNode(providedName = DUMMY_BANK_A_NAME, rpcUsers = listOf(demoUser)),
+                    startNode(providedName = DUMMY_BANK_A_NAME, rpcUsers = listOf(demoUser), maximumHeapSize = "1g"),
-                    startNode(providedName = DUMMY_BANK_B_NAME, rpcUsers = listOf(demoUser)),
+                    startNode(providedName = DUMMY_BANK_B_NAME, rpcUsers = listOf(demoUser), maximumHeapSize = "1g"),
-                    startNode(providedName = BOC_NAME, rpcUsers = listOf(bankUser))
+                    startNode(providedName = BOC_NAME, rpcUsers = listOf(bankUser), maximumHeapSize = "1g")
             ).map { (it.getOrThrow() as InProcess) }
 
             val (nodeARpc, nodeBRpc) = listOf(nodeA, nodeB).map {

serialization/src/main/kotlin/net/corda/serialization/internal/SerializationScheme.kt

@@ -26,7 +26,8 @@ data class SerializationContextImpl @JvmOverloads constructor(override val prefe
                                                               override val encoding: SerializationEncoding?,
                                                               override val encodingWhitelist: EncodingWhitelist = NullEncodingWhitelist,
                                                               override val lenientCarpenterEnabled: Boolean = false,
-                                                              override val preventDataLoss: Boolean = false) : SerializationContext {
+                                                              override val preventDataLoss: Boolean = false,
+                                                              override val customSerializers: Set<SerializationCustomSerializer<*, *>> = emptySet()) : SerializationContext {
     /**
      * {@inheritDoc}
      */
@@ -56,6 +57,10 @@ data class SerializationContextImpl @JvmOverloads constructor(override val prefe
         })
     }
 
+    override fun withCustomSerializers(serializers: Set<SerializationCustomSerializer<*, *>>): SerializationContextImpl {
+        return copy(customSerializers = customSerializers.union(serializers))
+    }
+
     override fun withPreferredSerializationVersion(magic: SerializationMagic) = copy(preferredSerializationVersion = magic)
     override fun withEncoding(encoding: SerializationEncoding?) = copy(encoding = encoding)
     override fun withEncodingWhitelist(encodingWhitelist: EncodingWhitelist) = copy(encodingWhitelist = encodingWhitelist)

serialization/src/main/kotlin/net/corda/serialization/internal/amqp/AMQPSerializationScheme.kt

@@ -22,7 +22,10 @@ import java.util.*
 
 val AMQP_ENABLED get() = SerializationDefaults.P2P_CONTEXT.preferredSerializationVersion == amqpMagic
 
-data class SerializationFactoryCacheKey(val classWhitelist: ClassWhitelist, val deserializationClassLoader: ClassLoader, val preventDataLoss: Boolean)
+data class SerializationFactoryCacheKey(val classWhitelist: ClassWhitelist,
+                                        val deserializationClassLoader: ClassLoader,
+                                        val preventDataLoss: Boolean,
+                                        val customSerializers: Set<SerializationCustomSerializer<*, *>>)
 
 fun SerializerFactory.addToWhitelist(vararg types: Class<*>) {
     require(types.toSet().size == types.size) {
@@ -43,11 +46,12 @@ interface SerializerFactoryFactory {
 @KeepForDJVM
 abstract class AbstractAMQPSerializationScheme(
         private val cordappCustomSerializers: Set<SerializationCustomSerializer<*, *>>,
+        private val cordappSerializationWhitelists: Set<SerializationWhitelist>,
         maybeNotConcurrentSerializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory>,
         val sff: SerializerFactoryFactory = createSerializerFactoryFactory()
 ) : SerializationScheme {
     @DeleteForDJVM
-    constructor(cordapps: List<Cordapp>) : this(cordapps.customSerializers, AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
+    constructor(cordapps: List<Cordapp>) : this(cordapps.customSerializers, cordapps.serializationWhitelists, AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>(128).toSynchronised())
 
     // This is a bit gross but a broader check for ConcurrentMap is not allowed inside DJVM.
     private val serializerFactoriesForContexts: MutableMap<SerializationFactoryCacheKey, SerializerFactory> = if (maybeNotConcurrentSerializerFactoriesForContexts is AccessOrderLinkedHashMap<*, *>) {
@@ -98,9 +102,12 @@ abstract class AbstractAMQPSerializationScheme(
         @DeleteForDJVM
         val List<Cordapp>.customSerializers
             get() = flatMap { it.serializationCustomSerializers }.toSet()
+
+        @DeleteForDJVM
+        val List<Cordapp>.serializationWhitelists
+            get() = flatMap { it.serializationWhitelists }.toSet()
     }
 
-    // Parameter "context" is unused directly but passed in by reflection. Removing it will cause failures.
     private fun registerCustomSerializers(context: SerializationContext, factory: SerializerFactory) {
         with(factory) {
             register(publicKeySerializer)
@@ -135,9 +142,6 @@ abstract class AbstractAMQPSerializationScheme(
             register(net.corda.serialization.internal.amqp.custom.ContractAttachmentSerializer(this))
             registerNonDeterministicSerializers(factory)
         }
-        for (whitelistProvider in serializationWhitelists) {
-            factory.addToWhitelist(*whitelistProvider.whitelist.toTypedArray())
-        }
 
         // If we're passed in an external list we trust that, otherwise revert to looking at the scan of the
         // classpath to find custom serializers.
@@ -146,6 +150,15 @@ abstract class AbstractAMQPSerializationScheme(
                 factory.registerExternal(CorDappCustomSerializer(customSerializer, factory))
             }
         } else {
+            // This step is registering custom serializers, which have been added after node initialisation (i.e. via attachments during transaction verification).
+            // Note: the order between the registration of customSerializers and cordappCustomSerializers must be preserved as-is. The reason is the following:
+            // Currently, the serialization infrastructure does not support multiple versions of a class (the first one that is registered dominates).
+            // As a result, when inside a context with attachments class loader, we prioritize serializers loaded on-demand from attachments to serializers that had been
+            // loaded during node initialisation, by scanning the cordapps folder.
+            context.customSerializers.forEach { customSerializer ->
+                factory.registerExternal(CorDappCustomSerializer(customSerializer, factory))
+            }
+
             logger.debug("Custom Serializer list loaded - not scanning classpath")
             cordappCustomSerializers.forEach { customSerializer ->
                 factory.registerExternal(CorDappCustomSerializer(customSerializer, factory))
@@ -159,6 +172,17 @@ abstract class AbstractAMQPSerializationScheme(
         }
     }
 
+    private fun registerCustomWhitelists(factory: SerializerFactory) {
+        serializationWhitelists.forEach {
+            factory.addToWhitelist(*it.whitelist.toTypedArray())
+        }
+        cordappSerializationWhitelists.forEach {
+            it.whitelist.forEach {
+                clazz -> factory.addToWhitelist(clazz)
+            }
+        }
+    }
+
     /*
      * Register the serializers which will be excluded from the DJVM.
      */
@@ -176,7 +200,7 @@ abstract class AbstractAMQPSerializationScheme(
     open val publicKeySerializer: CustomSerializer<*> = net.corda.serialization.internal.amqp.custom.PublicKeySerializer
 
     fun getSerializerFactory(context: SerializationContext): SerializerFactory {
-        val key = SerializationFactoryCacheKey(context.whitelist, context.deserializationClassLoader, context.preventDataLoss)
+        val key = SerializationFactoryCacheKey(context.whitelist, context.deserializationClassLoader, context.preventDataLoss, context.customSerializers)
         // ConcurrentHashMap.get() is lock free, but computeIfAbsent is not, even if the key is in the map already.
         return serializerFactoriesForContexts[key] ?: serializerFactoriesForContexts.computeIfAbsent(key) {
             when (context.useCase) {
@@ -187,6 +211,7 @@ abstract class AbstractAMQPSerializationScheme(
                 else -> sff.make(context)
             }.also {
                 registerCustomSerializers(context, it)
+                registerCustomWhitelists(it)
             }
         }
     }

serialization/src/test/kotlin/net/corda/serialization/internal/amqp/AbstractAMQPSerializationSchemeTest.kt

@@ -40,7 +40,7 @@ class AbstractAMQPSerializationSchemeTest {
         val factory = SerializerFactoryBuilder.build(TESTING_CONTEXT.whitelist, TESTING_CONTEXT.deserializationClassLoader)
         val maxFactories = 512
         val backingMap = AccessOrderLinkedHashMap<SerializationFactoryCacheKey, SerializerFactory>({ maxFactories }).toSynchronised()
-        val scheme = object : AbstractAMQPSerializationScheme(emptySet(), backingMap, createSerializerFactoryFactory()) {
+        val scheme = object : AbstractAMQPSerializationScheme(emptySet(), emptySet(), backingMap, createSerializerFactoryFactory()) {
             override fun rpcClientSerializerFactory(context: SerializationContext): SerializerFactory {
                 return factory
             }

testing/node-driver/src/main/kotlin/net/corda/testing/node/NotarySpec.kt

@@ -20,7 +20,19 @@ data class NotarySpec(
         val rpcUsers: List<User> = emptyList(),
         val verifierType: VerifierType = VerifierType.InMemory,
         val cluster: ClusterSpec? = null
-)
+) {
+    // These extra fields are handled this way to preserve Kotlin wire compatibility wrt additional parameters with default values.
+    constructor(name: CordaX500Name,
+                validating: Boolean = true,
+                rpcUsers: List<User> = emptyList(),
+                verifierType: VerifierType = VerifierType.InMemory,
+                cluster: ClusterSpec? = null,
+                maximumHeapSize: String = "512m"): this(name, validating, rpcUsers, verifierType, cluster) {
+        this.maximumHeapSize = maximumHeapSize
+    }
+
+    var maximumHeapSize: String = "512m"
+}
 
 /**
  * Abstract class specifying information about the consensus algorithm used for a cluster of nodes.

testing/node-driver/src/main/kotlin/net/corda/testing/node/internal/DriverDSLImpl.kt

@@ -488,7 +488,7 @@ class DriverDSLImpl(
         return startRegisteredNode(
                 spec.name,
                 localNetworkMap,
-                NodeParameters(rpcUsers = spec.rpcUsers, verifierType = spec.verifierType, customOverrides = notaryConfig + customOverrides)
+                NodeParameters(rpcUsers = spec.rpcUsers, verifierType = spec.verifierType, customOverrides = notaryConfig + customOverrides, maximumHeapSize = spec.maximumHeapSize)
         ).map { listOf(it) }
     }
 

webserver/src/integration-test/kotlin/net/corda/webserver/WebserverDriverTests.kt

@@ -31,7 +31,7 @@ class WebserverDriverTests {
     fun `starting a node and independent web server works`() {
         val addr = driver(DriverParameters(notarySpecs = emptyList())) {
             val node = startNode(providedName = DUMMY_BANK_A_NAME).getOrThrow()
-            val webserverHandle = startWebserver(node).getOrThrow()
+            val webserverHandle = startWebserver(node, "512m").getOrThrow()
             webserverMustBeUp(webserverHandle)
             webserverHandle.listenAddress
         }

webserver/src/main/kotlin/net/corda/webserver/internal/NodeWebServer.kt

@@ -199,7 +199,7 @@ class NodeWebServer(val config: WebServerConfig) {
 
     private fun connectLocalRpcAsNodeUser(): CordaRPCOps {
         log.info("Connecting to node at ${config.rpcAddress} as ${config.runAs}")
-        val client = CordaRPCClient(config.rpcAddress)
+        val client = CordaRPCClient(config.rpcAddress, classLoader = javaClass.classLoader)
         val connection = client.start(config.runAs.username, config.runAs.password)
         return connection.proxy
     }