diff --git a/build.gradle b/build.gradle
index 0d2d8ec9a4..1ee0c3a42a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -46,6 +46,7 @@ buildscript {
     ext.log4j_version = '2.9.1'
     ext.bouncycastle_version = constants.getProperty("bouncycastleVersion")
     ext.guava_version = constants.getProperty("guavaVersion")
+    ext.caffeine_version = constants.getProperty("caffeineVersion")
     ext.okhttp_version = '3.5.0'
     ext.netty_version = '4.1.9.Final'
     ext.typesafe_config_version = constants.getProperty("typesafeConfigVersion")
diff --git a/client/jfx/src/main/kotlin/net/corda/client/jfx/model/NetworkIdentityModel.kt b/client/jfx/src/main/kotlin/net/corda/client/jfx/model/NetworkIdentityModel.kt
index 5451f2acce..181fa895e6 100644
--- a/client/jfx/src/main/kotlin/net/corda/client/jfx/model/NetworkIdentityModel.kt
+++ b/client/jfx/src/main/kotlin/net/corda/client/jfx/model/NetworkIdentityModel.kt
@@ -1,7 +1,6 @@
 package net.corda.client.jfx.model
 
-import com.google.common.cache.CacheBuilder
-import com.google.common.cache.CacheLoader
+import com.github.benmanes.caffeine.cache.Caffeine
 import javafx.beans.value.ObservableValue
 import javafx.collections.FXCollections
 import javafx.collections.ObservableList
@@ -32,8 +31,8 @@ class NetworkIdentityModel {
 
     private val rpcProxy by observableValue(NodeMonitorModel::proxyObservable)
 
-    private val identityCache = CacheBuilder.newBuilder()
-            .build<PublicKey, ObservableValue<NodeInfo?>>(CacheLoader.from { publicKey ->
+    private val identityCache = Caffeine.newBuilder()
+            .build<PublicKey, ObservableValue<NodeInfo?>>({ publicKey ->
                 publicKey?.let { rpcProxy.map { it?.nodeInfoFromParty(AnonymousParty(publicKey)) } }
             })
     val notaries = ChosenList(rpcProxy.map { FXCollections.observableList(it?.notaryIdentities() ?: emptyList()) })
@@ -42,5 +41,5 @@ class NetworkIdentityModel {
             .filtered { it.legalIdentities.all { it !in notaries } }
     val myIdentity = rpcProxy.map { it?.nodeInfo()?.legalIdentitiesAndCerts?.first()?.party }
 
-    fun partyFromPublicKey(publicKey: PublicKey): ObservableValue<NodeInfo?> = identityCache[publicKey]
+    fun partyFromPublicKey(publicKey: PublicKey): ObservableValue<NodeInfo?> = identityCache[publicKey]!!
 }
diff --git a/client/rpc/build.gradle b/client/rpc/build.gradle
index 3b585cf164..d60a6eb8d5 100644
--- a/client/rpc/build.gradle
+++ b/client/rpc/build.gradle
@@ -68,6 +68,9 @@ dependencies {
     compile project(':core')
     compile project(':node-api')
 
+    // For caches rather than guava
+    compile "com.github.ben-manes.caffeine:caffeine:$caffeine_version"
+
     // Unit testing helpers.
     testCompile "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
     testCompile "junit:junit:$junit_version"
diff --git a/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClient.kt b/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClient.kt
index 79ad14f5dd..26d027e287 100644
--- a/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClient.kt
+++ b/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClient.kt
@@ -44,12 +44,6 @@ data class RPCClientConfiguration(
         val reapInterval: Duration,
         /** The number of threads to use for observations (for executing [Observable.onNext]) */
         val observationExecutorPoolSize: Int,
-        /**
-         * Determines the concurrency level of the Observable Cache. This is exposed because it implicitly determines
-         * the limit on the number of leaked observables reaped because of garbage collection per reaping.
-         * See the implementation of [com.google.common.cache.LocalCache] for details.
-         */
-        val cacheConcurrencyLevel: Int,
         /** The retry interval of artemis connections in milliseconds */
         val connectionRetryInterval: Duration,
         /** The retry interval multiplier for exponential backoff */
@@ -71,7 +65,6 @@ data class RPCClientConfiguration(
                 trackRpcCallSites = false,
                 reapInterval = 1.seconds,
                 observationExecutorPoolSize = 4,
-                cacheConcurrencyLevel = 8,
                 connectionRetryInterval = 5.seconds,
                 connectionRetryIntervalMultiplier = 1.5,
                 connectionMaxRetryInterval = 3.minutes,
diff --git a/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClientProxyHandler.kt b/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClientProxyHandler.kt
index 54b931ed8d..6964fe493d 100644
--- a/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClientProxyHandler.kt
+++ b/client/rpc/src/main/kotlin/net/corda/client/rpc/internal/RPCClientProxyHandler.kt
@@ -1,13 +1,14 @@
 package net.corda.client.rpc.internal
 
+import co.paralleluniverse.common.util.SameThreadExecutor
 import com.esotericsoftware.kryo.Kryo
 import com.esotericsoftware.kryo.Serializer
 import com.esotericsoftware.kryo.io.Input
 import com.esotericsoftware.kryo.io.Output
-import com.google.common.cache.Cache
-import com.google.common.cache.CacheBuilder
-import com.google.common.cache.RemovalCause
-import com.google.common.cache.RemovalListener
+import com.github.benmanes.caffeine.cache.Cache
+import com.github.benmanes.caffeine.cache.Caffeine
+import com.github.benmanes.caffeine.cache.RemovalCause
+import com.github.benmanes.caffeine.cache.RemovalListener
 import com.google.common.util.concurrent.SettableFuture
 import com.google.common.util.concurrent.ThreadFactoryBuilder
 import net.corda.client.rpc.RPCException
@@ -142,10 +143,10 @@ class RPCClientProxyHandler(
     private val serializationContextWithObservableContext = RpcClientObservableSerializer.createContext(serializationContext, observableContext)
 
     private fun createRpcObservableMap(): RpcObservableMap {
-        val onObservableRemove = RemovalListener<InvocationId, UnicastSubject<Notification<*>>> {
-            val observableId = it.key!!
+        val onObservableRemove = RemovalListener<InvocationId, UnicastSubject<Notification<*>>> { key, value, cause ->
+            val observableId = key!!
             val rpcCallSite = callSiteMap?.remove(observableId)
-            if (it.cause == RemovalCause.COLLECTED) {
+            if (cause == RemovalCause.COLLECTED) {
                 log.warn(listOf(
                         "A hot observable returned from an RPC was never subscribed to.",
                         "This wastes server-side resources because it was queueing observations for retrieval.",
@@ -156,10 +157,9 @@ class RPCClientProxyHandler(
             }
             observablesToReap.locked { observables.add(observableId) }
         }
-        return CacheBuilder.newBuilder().
+        return Caffeine.newBuilder().
                 weakValues().
-                removalListener(onObservableRemove).
-                concurrencyLevel(rpcConfiguration.cacheConcurrencyLevel).
+                removalListener(onObservableRemove).executor(SameThreadExecutor.getExecutor()).
                 build()
     }
 
diff --git a/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCConcurrencyTests.kt b/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCConcurrencyTests.kt
index 5ea77a66fd..fe405b37af 100644
--- a/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCConcurrencyTests.kt
+++ b/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCConcurrencyTests.kt
@@ -91,8 +91,7 @@ class RPCConcurrencyTests : AbstractRPCTest() {
         return testProxy<TestOps>(
                 TestOpsImpl(pool),
                 clientConfiguration = RPCClientConfiguration.default.copy(
-                        reapInterval = 100.millis,
-                        cacheConcurrencyLevel = 16
+                        reapInterval = 100.millis
                 ),
                 serverConfiguration = RPCServerConfiguration.default.copy(
                         rpcThreadPoolSize = 4
diff --git a/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCPerformanceTests.kt b/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCPerformanceTests.kt
index 689674d22f..0211d0b3ec 100644
--- a/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCPerformanceTests.kt
+++ b/client/rpc/src/test/kotlin/net/corda/client/rpc/RPCPerformanceTests.kt
@@ -87,7 +87,6 @@ class RPCPerformanceTests : AbstractRPCTest() {
             rpcDriver {
                 val proxy = testProxy(
                         RPCClientConfiguration.default.copy(
-                                cacheConcurrencyLevel = 16,
                                 observationExecutorPoolSize = 2
                         ),
                         RPCServerConfiguration.default.copy(
@@ -127,8 +126,7 @@ class RPCPerformanceTests : AbstractRPCTest() {
             val metricRegistry = startReporter(shutdownManager)
             val proxy = testProxy(
                     RPCClientConfiguration.default.copy(
-                            reapInterval = 1.seconds,
-                            cacheConcurrencyLevel = 16
+                            reapInterval = 1.seconds
                     ),
                     RPCServerConfiguration.default.copy(
                             rpcThreadPoolSize = 8
diff --git a/constants.properties b/constants.properties
index 3f219493b2..134d656085 100644
--- a/constants.properties
+++ b/constants.properties
@@ -7,3 +7,4 @@ typesafeConfigVersion=1.3.1
 jsr305Version=3.0.2
 artifactoryPluginVersion=4.4.18
 snakeYamlVersion=1.19
+caffeineVersion=2.6.2
diff --git a/node-api/build.gradle b/node-api/build.gradle
index 6cc03bd117..405221b374 100644
--- a/node-api/build.gradle
+++ b/node-api/build.gradle
@@ -40,6 +40,9 @@ dependencies {
     // Pure-Java Snappy compression
     compile 'org.iq80.snappy:snappy:0.4'
 
+    // For caches rather than guava
+    compile "com.github.ben-manes.caffeine:caffeine:$caffeine_version"
+
     // Unit testing helpers.
     testCompile "junit:junit:$junit_version"
     testCompile "org.assertj:assertj-core:$assertj_version"
diff --git a/node-api/src/main/kotlin/net/corda/nodeapi/internal/DeduplicationChecker.kt b/node-api/src/main/kotlin/net/corda/nodeapi/internal/DeduplicationChecker.kt
index b35b8922a3..86742c6325 100644
--- a/node-api/src/main/kotlin/net/corda/nodeapi/internal/DeduplicationChecker.kt
+++ b/node-api/src/main/kotlin/net/corda/nodeapi/internal/DeduplicationChecker.kt
@@ -1,7 +1,7 @@
 package net.corda.nodeapi.internal
 
-import com.google.common.cache.CacheBuilder
-import com.google.common.cache.CacheLoader
+import com.github.benmanes.caffeine.cache.CacheLoader
+import com.github.benmanes.caffeine.cache.Caffeine
 import java.time.Duration
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicLong
@@ -11,11 +11,11 @@ import java.util.concurrent.atomic.AtomicLong
  */
 class DeduplicationChecker(cacheExpiry: Duration) {
     // dedupe identity -> watermark cache
-    private val watermarkCache = CacheBuilder.newBuilder()
+    private val watermarkCache = Caffeine.newBuilder()
             .expireAfterAccess(cacheExpiry.toNanos(), TimeUnit.NANOSECONDS)
             .build(WatermarkCacheLoader)
 
-    private object WatermarkCacheLoader : CacheLoader<Any, AtomicLong>() {
+    private object WatermarkCacheLoader : CacheLoader<Any, AtomicLong> {
         override fun load(key: Any) = AtomicLong(-1)
     }
 
@@ -25,6 +25,7 @@ class DeduplicationChecker(cacheExpiry: Duration) {
      * @return true if the message is unique, false if it's a duplicate.
      */
     fun checkDuplicateMessageId(identity: Any, sequenceNumber: Long): Boolean {
-        return watermarkCache[identity].getAndUpdate { maxOf(sequenceNumber, it) } >= sequenceNumber
+        return watermarkCache[identity]!!.getAndUpdate { maxOf(sequenceNumber, it) } >= sequenceNumber
     }
 }
+
diff --git a/node-api/src/main/kotlin/net/corda/nodeapi/internal/serialization/SerializationScheme.kt b/node-api/src/main/kotlin/net/corda/nodeapi/internal/serialization/SerializationScheme.kt
index a093bc871b..369978bb62 100644
--- a/node-api/src/main/kotlin/net/corda/nodeapi/internal/serialization/SerializationScheme.kt
+++ b/node-api/src/main/kotlin/net/corda/nodeapi/internal/serialization/SerializationScheme.kt
@@ -1,7 +1,7 @@
 package net.corda.nodeapi.internal.serialization
 
-import com.google.common.cache.Cache
-import com.google.common.cache.CacheBuilder
+import com.github.benmanes.caffeine.cache.Cache
+import com.github.benmanes.caffeine.cache.Caffeine
 import net.corda.core.contracts.Attachment
 import net.corda.core.crypto.SecureHash
 import net.corda.core.internal.copyBytes
@@ -30,7 +30,7 @@ data class SerializationContextImpl @JvmOverloads constructor(override val prefe
                                                               override val useCase: SerializationContext.UseCase,
                                                               override val encoding: SerializationEncoding?,
                                                               override val encodingWhitelist: EncodingWhitelist = NullEncodingWhitelist) : SerializationContext {
-    private val cache: Cache<List<SecureHash>, AttachmentsClassLoader> = CacheBuilder.newBuilder().weakValues().maximumSize(1024).build()
+    private val cache: Cache<List<SecureHash>, AttachmentsClassLoader> = Caffeine.newBuilder().weakValues().maximumSize(1024).build()
 
     /**
      * {@inheritDoc}
@@ -49,7 +49,7 @@ data class SerializationContextImpl @JvmOverloads constructor(override val prefe
                 }
                 missing.isNotEmpty() && throw MissingAttachmentsException(missing)
                 AttachmentsClassLoader(attachments, parent = deserializationClassLoader)
-            })
+            }!!)
         } catch (e: ExecutionException) {
             // Caught from within the cache get, so unwrap.
             throw e.cause!!
diff --git a/node/build.gradle b/node/build.gradle
index 74cad1b2ef..2158c98b2c 100644
--- a/node/build.gradle
+++ b/node/build.gradle
@@ -79,6 +79,9 @@ dependencies {
 
     compile "com.google.guava:guava:$guava_version"
 
+    // For caches rather than guava
+    compile "com.github.ben-manes.caffeine:caffeine:$caffeine_version"
+
     // JOpt: for command line flags.
     compile "net.sf.jopt-simple:jopt-simple:$jopt_simple_version"
 
diff --git a/node/src/main/kotlin/net/corda/node/internal/security/RPCSecurityManagerImpl.kt b/node/src/main/kotlin/net/corda/node/internal/security/RPCSecurityManagerImpl.kt
index 4b1daabdde..eec5d8ff33 100644
--- a/node/src/main/kotlin/net/corda/node/internal/security/RPCSecurityManagerImpl.kt
+++ b/node/src/main/kotlin/net/corda/node/internal/security/RPCSecurityManagerImpl.kt
@@ -1,7 +1,8 @@
 package net.corda.node.internal.security
 
-import com.google.common.cache.CacheBuilder
-import com.google.common.cache.Cache
+
+import com.github.benmanes.caffeine.cache.Cache
+import com.github.benmanes.caffeine.cache.Caffeine
 import com.google.common.primitives.Ints
 import net.corda.core.context.AuthServiceId
 import net.corda.core.utilities.loggerFor
@@ -94,7 +95,7 @@ class RPCSecurityManagerImpl(config: AuthServiceConfig) : RPCSecurityManager {
             return DefaultSecurityManager(realm).also {
                 // Setup optional cache layer if configured
                 it.cacheManager = config.options?.cache?.let {
-                    GuavaCacheManager(
+                    CaffeineCacheManager(
                             timeToLiveSeconds = it.expireAfterSecs,
                             maxSize = it.maxEntries)
                 }
@@ -257,9 +258,9 @@ private class NodeJdbcRealm(config: SecurityConfiguration.AuthService.DataSource
 private typealias ShiroCache<K, V> = org.apache.shiro.cache.Cache<K, V>
 
 /*
- * Adapts a [com.google.common.cache.Cache] to a [org.apache.shiro.cache.Cache] implementation.
+ * Adapts a [com.github.benmanes.caffeine.cache.Cache] to a [org.apache.shiro.cache.Cache] implementation.
  */
-private fun <K, V> Cache<K, V>.toShiroCache(name: String) = object : ShiroCache<K, V> {
+private fun <K : Any, V> Cache<K, V>.toShiroCache(name: String) = object : ShiroCache<K, V> {
 
     val name = name
     private val impl = this@toShiroCache
@@ -282,7 +283,7 @@ private fun <K, V> Cache<K, V>.toShiroCache(name: String) = object : ShiroCache<
         impl.invalidateAll()
     }
 
-    override fun size() = Ints.checkedCast(impl.size())
+    override fun size() = Ints.checkedCast(impl.estimatedSize())
     override fun keys() = impl.asMap().keys
     override fun values() = impl.asMap().values
     override fun toString() = "Guava cache adapter [$impl]"
@@ -290,22 +291,22 @@ private fun <K, V> Cache<K, V>.toShiroCache(name: String) = object : ShiroCache<
 
 /*
  * Implementation of [org.apache.shiro.cache.CacheManager] based on
- * cache implementation in [com.google.common.cache]
+ * cache implementation in [com.github.benmanes.caffeine.cache.Cache]
  */
-private class GuavaCacheManager(val maxSize: Long,
-                                val timeToLiveSeconds: Long) : CacheManager {
+private class CaffeineCacheManager(val maxSize: Long,
+                                   val timeToLiveSeconds: Long) : CacheManager {
 
     private val instances = ConcurrentHashMap<String, ShiroCache<*, *>>()
 
-    override fun <K, V> getCache(name: String): ShiroCache<K, V> {
+    override fun <K : Any, V> getCache(name: String): ShiroCache<K, V> {
         val result = instances[name] ?: buildCache<K, V>(name)
         instances.putIfAbsent(name, result)
         return result as ShiroCache<K, V>
     }
 
-    private fun <K, V> buildCache(name: String) : ShiroCache<K, V> {
+    private fun <K : Any, V> buildCache(name: String): ShiroCache<K, V> {
         logger.info("Constructing cache '$name' with maximumSize=$maxSize, TTL=${timeToLiveSeconds}s")
-        return CacheBuilder.newBuilder()
+        return Caffeine.newBuilder()
                 .expireAfterWrite(timeToLiveSeconds, TimeUnit.SECONDS)
                 .maximumSize(maxSize)
                 .build<K, V>()
@@ -313,6 +314,6 @@ private class GuavaCacheManager(val maxSize: Long,
     }
 
     companion object {
-        private val logger = loggerFor<GuavaCacheManager>()
+        private val logger = loggerFor<CaffeineCacheManager>()
     }
 }
\ No newline at end of file
diff --git a/node/src/main/kotlin/net/corda/node/services/messaging/RPCServer.kt b/node/src/main/kotlin/net/corda/node/services/messaging/RPCServer.kt
index 657de9535e..e70f80d39d 100644
--- a/node/src/main/kotlin/net/corda/node/services/messaging/RPCServer.kt
+++ b/node/src/main/kotlin/net/corda/node/services/messaging/RPCServer.kt
@@ -1,12 +1,13 @@
 package net.corda.node.services.messaging
 
+import co.paralleluniverse.common.util.SameThreadExecutor
 import com.esotericsoftware.kryo.Kryo
 import com.esotericsoftware.kryo.Serializer
 import com.esotericsoftware.kryo.io.Input
 import com.esotericsoftware.kryo.io.Output
-import com.google.common.cache.Cache
-import com.google.common.cache.CacheBuilder
-import com.google.common.cache.RemovalListener
+import com.github.benmanes.caffeine.cache.Cache
+import com.github.benmanes.caffeine.cache.Caffeine
+import com.github.benmanes.caffeine.cache.RemovalListener
 import com.google.common.collect.HashMultimap
 import com.google.common.collect.Multimaps
 import com.google.common.collect.SetMultimap
@@ -145,11 +146,11 @@ class RPCServer(
     }
 
     private fun createObservableSubscriptionMap(): ObservableSubscriptionMap {
-        val onObservableRemove = RemovalListener<InvocationId, ObservableSubscription> {
-            log.debug { "Unsubscribing from Observable with id ${it.key} because of ${it.cause}" }
-            it.value.subscription.unsubscribe()
+        val onObservableRemove = RemovalListener<InvocationId, ObservableSubscription> { key, value, cause ->
+            log.debug { "Unsubscribing from Observable with id ${key} because of ${cause}" }
+            value!!.subscription.unsubscribe()
         }
-        return CacheBuilder.newBuilder().removalListener(onObservableRemove).build()
+        return Caffeine.newBuilder().removalListener(onObservableRemove).executor(SameThreadExecutor.getExecutor()).build()
     }
 
     fun start(activeMqServerControl: ActiveMQServerControl) {
diff --git a/node/src/main/kotlin/net/corda/node/services/network/PersistentNetworkMapCache.kt b/node/src/main/kotlin/net/corda/node/services/network/PersistentNetworkMapCache.kt
index 19fb9fd875..caefa2d3d6 100644
--- a/node/src/main/kotlin/net/corda/node/services/network/PersistentNetworkMapCache.kt
+++ b/node/src/main/kotlin/net/corda/node/services/network/PersistentNetworkMapCache.kt
@@ -164,9 +164,9 @@ open class PersistentNetworkMapCache(
 
     override fun getNodesByLegalName(name: CordaX500Name): List<NodeInfo> = database.transaction { queryByLegalName(session, name) }
 
-    override fun getNodesByLegalIdentityKey(identityKey: PublicKey): List<NodeInfo> = nodesByKeyCache[identityKey]
+    override fun getNodesByLegalIdentityKey(identityKey: PublicKey): List<NodeInfo> = nodesByKeyCache[identityKey]!!
 
-    private val nodesByKeyCache = NonInvalidatingCache<PublicKey, List<NodeInfo>>(1024, 8, { key -> database.transaction { queryByIdentityKey(session, key) } })
+    private val nodesByKeyCache = NonInvalidatingCache<PublicKey, List<NodeInfo>>(1024, { key -> database.transaction { queryByIdentityKey(session, key) } })
 
     override fun getNodesByOwningKeyIndex(identityKeyIndex: String): List<NodeInfo> {
         return database.transaction {
@@ -176,9 +176,9 @@ open class PersistentNetworkMapCache(
 
     override fun getNodeByAddress(address: NetworkHostAndPort): NodeInfo? = database.transaction { queryByAddress(session, address) }
 
-    override fun getPeerCertificateByLegalName(name: CordaX500Name): PartyAndCertificate? = identityByLegalNameCache.get(name).orElse(null)
+    override fun getPeerCertificateByLegalName(name: CordaX500Name): PartyAndCertificate? = identityByLegalNameCache.get(name)!!.orElse(null)
 
-    private val identityByLegalNameCache = NonInvalidatingCache<CordaX500Name, Optional<PartyAndCertificate>>(1024, 8, { name -> Optional.ofNullable(database.transaction { queryIdentityByLegalName(session, name) }) })
+    private val identityByLegalNameCache = NonInvalidatingCache<CordaX500Name, Optional<PartyAndCertificate>>(1024, { name -> Optional.ofNullable(database.transaction { queryIdentityByLegalName(session, name) }) })
 
     override fun track(): DataFeed<List<NodeInfo>, MapChange> {
         synchronized(_changed) {
diff --git a/node/src/main/kotlin/net/corda/node/services/persistence/NodeAttachmentService.kt b/node/src/main/kotlin/net/corda/node/services/persistence/NodeAttachmentService.kt
index 9593cfc634..e4ea68a1e6 100644
--- a/node/src/main/kotlin/net/corda/node/services/persistence/NodeAttachmentService.kt
+++ b/node/src/main/kotlin/net/corda/node/services/persistence/NodeAttachmentService.kt
@@ -1,7 +1,7 @@
 package net.corda.node.services.persistence
 
 import com.codahale.metrics.MetricRegistry
-import com.google.common.cache.Weigher
+import com.github.benmanes.caffeine.cache.Weigher
 import com.google.common.hash.HashCode
 import com.google.common.hash.Hashing
 import com.google.common.hash.HashingInputStream
@@ -24,7 +24,6 @@ import net.corda.node.services.config.NodeConfiguration
 import net.corda.node.services.vault.HibernateAttachmentQueryCriteriaParser
 import net.corda.node.utilities.NonInvalidatingCache
 import net.corda.node.utilities.NonInvalidatingWeightBasedCache
-import net.corda.node.utilities.defaultCordaCacheConcurrencyLevel
 import net.corda.nodeapi.internal.persistence.NODE_DATABASE_PREFIX
 import net.corda.nodeapi.internal.persistence.currentDBSession
 import net.corda.nodeapi.internal.withContractsInJar
@@ -209,7 +208,6 @@ class NodeAttachmentService(
 
     private val attachmentContentCache = NonInvalidatingWeightBasedCache<SecureHash, Optional<Pair<Attachment, ByteArray>>>(
             maxWeight = attachmentContentCacheSize,
-            concurrencyLevel = defaultCordaCacheConcurrencyLevel,
             weigher = object : Weigher<SecureHash, Optional<Pair<Attachment, ByteArray>>> {
                 override fun weigh(key: SecureHash, value: Optional<Pair<Attachment, ByteArray>>): Int {
                     return key.size + if (value.isPresent) value.get().second.size else 0
@@ -234,12 +232,11 @@ class NodeAttachmentService(
 
     private val attachmentCache = NonInvalidatingCache<SecureHash, Optional<Attachment>>(
             attachmentCacheBound,
-            defaultCordaCacheConcurrencyLevel,
             { key -> Optional.ofNullable(createAttachment(key)) }
     )
 
     private fun createAttachment(key: SecureHash): Attachment? {
-        val content = attachmentContentCache.get(key)
+        val content = attachmentContentCache.get(key)!!
         if (content.isPresent) {
             return content.get().first
         }
@@ -249,7 +246,7 @@ class NodeAttachmentService(
     }
 
     override fun openAttachment(id: SecureHash): Attachment? {
-        val attachment = attachmentCache.get(id)
+        val attachment = attachmentCache.get(id)!!
         if (attachment.isPresent) {
             return attachment.get()
         }
diff --git a/node/src/main/kotlin/net/corda/node/utilities/AppendOnlyPersistentMap.kt b/node/src/main/kotlin/net/corda/node/utilities/AppendOnlyPersistentMap.kt
index c6b875dbd9..ad3df17747 100644
--- a/node/src/main/kotlin/net/corda/node/utilities/AppendOnlyPersistentMap.kt
+++ b/node/src/main/kotlin/net/corda/node/utilities/AppendOnlyPersistentMap.kt
@@ -1,7 +1,7 @@
 package net.corda.node.utilities
 
-import com.google.common.cache.LoadingCache
-import com.google.common.cache.Weigher
+import com.github.benmanes.caffeine.cache.LoadingCache
+import com.github.benmanes.caffeine.cache.Weigher
 import net.corda.core.utilities.contextLogger
 import net.corda.nodeapi.internal.persistence.currentDBSession
 import java.util.*
@@ -29,7 +29,7 @@ abstract class AppendOnlyPersistentMapBase<K, V, E, out EK>(
      * Returns the value associated with the key, first loading that value from the storage if necessary.
      */
     operator fun get(key: K): V? {
-        return cache.get(key).orElse(null)
+        return cache.get(key)!!.orElse(null)
     }
 
     val size get() = allPersisted().toList().size
@@ -62,7 +62,7 @@ abstract class AppendOnlyPersistentMapBase<K, V, E, out EK>(
             } else {
                 Optional.of(value)
             }
-        }
+        }!!
         if (!insertionAttempt) {
             if (existingInCache.isPresent) {
                 // Key already exists in cache, do nothing.
@@ -71,7 +71,7 @@ abstract class AppendOnlyPersistentMapBase<K, V, E, out EK>(
                 // This happens when the key was queried before with no value associated. We invalidate the cached null
                 // value and recursively call set again. This is to avoid race conditions where another thread queries after
                 // the invalidate but before the set.
-                cache.invalidate(key)
+                cache.invalidate(key!!)
                 return set(key, value, logWarning, store)
             }
         }
@@ -148,7 +148,6 @@ class AppendOnlyPersistentMap<K, V, E, out EK>(
     //TODO determine cacheBound based on entity class later or with node config allowing tuning, or using some heuristic based on heap size
     override val cache = NonInvalidatingCache<K, Optional<V>>(
             bound = cacheBound,
-            concurrencyLevel = 8,
             loadFunction = { key -> Optional.ofNullable(loadValue(key)) })
 }
 
@@ -166,7 +165,6 @@ class WeightBasedAppendOnlyPersistentMap<K, V, E, out EK>(
         persistentEntityClass) {
     override val cache = NonInvalidatingWeightBasedCache<K, Optional<V>>(
             maxWeight = maxWeight,
-            concurrencyLevel = 8,
             weigher = object : Weigher<K, Optional<V>> {
                 override fun weigh(key: K, value: Optional<V>): Int {
                     return weighingFunc(key, value)
diff --git a/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingCache.kt b/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingCache.kt
index f08a0631cb..d8840bacc2 100644
--- a/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingCache.kt
+++ b/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingCache.kt
@@ -1,29 +1,28 @@
 package net.corda.node.utilities
 
-import com.google.common.cache.CacheBuilder
-import com.google.common.cache.CacheLoader
-import com.google.common.cache.LoadingCache
-import com.google.common.cache.Weigher
-import com.google.common.util.concurrent.ListenableFuture
+import com.github.benmanes.caffeine.cache.CacheLoader
+import com.github.benmanes.caffeine.cache.Caffeine
+import com.github.benmanes.caffeine.cache.LoadingCache
+import com.github.benmanes.caffeine.cache.Weigher
 
 
 class NonInvalidatingCache<K, V> private constructor(
         val cache: LoadingCache<K, V>
 ) : LoadingCache<K, V> by cache {
 
-    constructor(bound: Long, concurrencyLevel: Int, loadFunction: (K) -> V) :
-            this(buildCache(bound, concurrencyLevel, loadFunction))
+    constructor(bound: Long, loadFunction: (K) -> V) :
+            this(buildCache(bound, loadFunction))
 
     private companion object {
-        private fun <K, V> buildCache(bound: Long, concurrencyLevel: Int, loadFunction: (K) -> V): LoadingCache<K, V> {
-            val builder = CacheBuilder.newBuilder().maximumSize(bound).concurrencyLevel(concurrencyLevel)
+        private fun <K, V> buildCache(bound: Long, loadFunction: (K) -> V): LoadingCache<K, V> {
+            val builder = Caffeine.newBuilder().maximumSize(bound)
             return builder.build(NonInvalidatingCacheLoader(loadFunction))
         }
     }
 
     // TODO look into overriding loadAll() if we ever use it
-    class NonInvalidatingCacheLoader<K, V>(val loadFunction: (K) -> V) : CacheLoader<K, V>() {
-        override fun reload(key: K, oldValue: V): ListenableFuture<V> {
+    class NonInvalidatingCacheLoader<K, V>(val loadFunction: (K) -> V) : CacheLoader<K, V> {
+        override fun reload(key: K, oldValue: V): V {
             throw IllegalStateException("Non invalidating cache refreshed")
         }
 
@@ -34,16 +33,14 @@ class NonInvalidatingCache<K, V> private constructor(
 class NonInvalidatingWeightBasedCache<K, V> private constructor(
         val cache: LoadingCache<K, V>
 ) : LoadingCache<K, V> by cache {
-    constructor (maxWeight: Long, concurrencyLevel: Int, weigher: Weigher<K, V>, loadFunction: (K) -> V) :
-            this(buildCache(maxWeight, concurrencyLevel, weigher, loadFunction))
+    constructor (maxWeight: Long, weigher: Weigher<K, V>, loadFunction: (K) -> V) :
+            this(buildCache(maxWeight, weigher, loadFunction))
 
 
     private companion object {
-        private fun <K, V> buildCache(maxWeight: Long, concurrencyLevel: Int, weigher: Weigher<K, V>, loadFunction: (K) -> V): LoadingCache<K, V> {
-            val builder = CacheBuilder.newBuilder().maximumWeight(maxWeight).weigher(weigher).concurrencyLevel(concurrencyLevel)
+        private fun <K, V> buildCache(maxWeight: Long, weigher: Weigher<K, V>, loadFunction: (K) -> V): LoadingCache<K, V> {
+            val builder = Caffeine.newBuilder().maximumWeight(maxWeight).weigher(weigher)
             return builder.build(NonInvalidatingCache.NonInvalidatingCacheLoader(loadFunction))
         }
     }
-}
-
-val defaultCordaCacheConcurrencyLevel: Int = 8
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingUnboundCache.kt b/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingUnboundCache.kt
index ea16bfd064..b1fef1d2e6 100644
--- a/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingUnboundCache.kt
+++ b/node/src/main/kotlin/net/corda/node/utilities/NonInvalidatingUnboundCache.kt
@@ -1,21 +1,23 @@
 package net.corda.node.utilities
 
-import com.google.common.cache.*
-import com.google.common.util.concurrent.ListenableFuture
-
+import co.paralleluniverse.common.util.SameThreadExecutor
+import com.github.benmanes.caffeine.cache.CacheLoader
+import com.github.benmanes.caffeine.cache.Caffeine
+import com.github.benmanes.caffeine.cache.LoadingCache
+import com.github.benmanes.caffeine.cache.RemovalListener
 
 class NonInvalidatingUnboundCache<K, V> private constructor(
         val cache: LoadingCache<K, V>
 ) : LoadingCache<K, V> by cache {
 
-    constructor(concurrencyLevel: Int, loadFunction: (K) -> V, removalListener: RemovalListener<K, V> = RemovalListener {},
+    constructor(loadFunction: (K) -> V, removalListener: RemovalListener<K, V> = RemovalListener { key, value, cause -> },
                 keysToPreload: () -> Iterable<K> = { emptyList() }) :
-            this(buildCache(concurrencyLevel, loadFunction, removalListener, keysToPreload))
+            this(buildCache(loadFunction, removalListener, keysToPreload))
 
     private companion object {
-        private fun <K, V> buildCache(concurrencyLevel: Int, loadFunction: (K) -> V, removalListener: RemovalListener<K, V>,
+        private fun <K, V> buildCache(loadFunction: (K) -> V, removalListener: RemovalListener<K, V>,
                                       keysToPreload: () -> Iterable<K>): LoadingCache<K, V> {
-            val builder = CacheBuilder.newBuilder().concurrencyLevel(concurrencyLevel).removalListener(removalListener)
+            val builder = Caffeine.newBuilder().removalListener(removalListener).executor(SameThreadExecutor.getExecutor())
             return builder.build(NonInvalidatingCacheLoader(loadFunction)).apply {
                 getAll(keysToPreload())
             }
@@ -23,8 +25,8 @@ class NonInvalidatingUnboundCache<K, V> private constructor(
     }
 
     // TODO look into overriding loadAll() if we ever use it
-    private class NonInvalidatingCacheLoader<K, V>(val loadFunction: (K) -> V) : CacheLoader<K, V>() {
-        override fun reload(key: K, oldValue: V): ListenableFuture<V> {
+    private class NonInvalidatingCacheLoader<K, V>(val loadFunction: (K) -> V) : CacheLoader<K, V> {
+        override fun reload(key: K, oldValue: V): V {
             throw IllegalStateException("Non invalidating cache refreshed")
         }
 
diff --git a/node/src/main/kotlin/net/corda/node/utilities/PersistentMap.kt b/node/src/main/kotlin/net/corda/node/utilities/PersistentMap.kt
index c023d113fb..d205e2be15 100644
--- a/node/src/main/kotlin/net/corda/node/utilities/PersistentMap.kt
+++ b/node/src/main/kotlin/net/corda/node/utilities/PersistentMap.kt
@@ -1,8 +1,7 @@
 package net.corda.node.utilities
 
-import com.google.common.cache.RemovalCause
-import com.google.common.cache.RemovalListener
-import com.google.common.cache.RemovalNotification
+import com.github.benmanes.caffeine.cache.RemovalCause
+import com.github.benmanes.caffeine.cache.RemovalListener
 import net.corda.core.utilities.contextLogger
 import net.corda.nodeapi.internal.persistence.currentDBSession
 import java.util.*
@@ -10,7 +9,7 @@ import java.util.*
 /**
  * Implements an unbound caching layer on top of a table accessed via Hibernate mapping.
  */
-class PersistentMap<K, V, E, out EK>(
+class PersistentMap<K : Any, V, E, out EK>(
         val toPersistentEntityKey: (K) -> EK,
         val fromPersistentEntity: (E) -> Pair<K, V>,
         val toPersistentEntity: (key: K, value: V) -> E,
@@ -22,7 +21,6 @@ class PersistentMap<K, V, E, out EK>(
     }
 
     private val cache = NonInvalidatingUnboundCache(
-            concurrencyLevel = 8,
             loadFunction = { key -> Optional.ofNullable(loadValue(key)) },
             removalListener = ExplicitRemoval(toPersistentEntityKey, persistentEntityClass)
     ).apply {
@@ -34,11 +32,11 @@ class PersistentMap<K, V, E, out EK>(
     }
 
     class ExplicitRemoval<K, V, E, EK>(private val toPersistentEntityKey: (K) -> EK, private val persistentEntityClass: Class<E>) : RemovalListener<K, V> {
-        override fun onRemoval(notification: RemovalNotification<K, V>?) {
-            when (notification?.cause) {
+        override fun onRemoval(key: K?, value: V?, cause: RemovalCause) {
+            when (cause) {
                 RemovalCause.EXPLICIT -> {
                     val session = currentDBSession()
-                    val elem = session.find(persistentEntityClass, toPersistentEntityKey(notification.key))
+                    val elem = session.find(persistentEntityClass, toPersistentEntityKey(key!!))
                     if (elem != null) {
                         session.remove(elem)
                     }
@@ -53,14 +51,14 @@ class PersistentMap<K, V, E, out EK>(
     }
 
     override operator fun get(key: K): V? {
-        return cache.get(key).orElse(null)
+        return cache.get(key)!!.orElse(null)
     }
 
     fun all(): Sequence<Pair<K, V>> {
         return cache.asMap().asSequence().filter { it.value.isPresent }.map { Pair(it.key, it.value.get()) }
     }
 
-    override val size get() = cache.size().toInt()
+    override val size get() = cache.estimatedSize().toInt()
 
     private tailrec fun set(key: K, value: V, logWarning: Boolean = true, store: (K, V) -> V?, replace: (K, V) -> Unit): Boolean {
         var insertionAttempt = false
@@ -72,7 +70,7 @@ class PersistentMap<K, V, E, out EK>(
             // Store the value, depending on store implementation this may replace existing entry in DB.
             store(key, value)
             Optional.of(value)
-        }
+        }!!
         if (!insertionAttempt) {
             if (existingInCache.isPresent) {
                 // Key already exists in cache, store the new value in the DB (depends on tore implementation) and refresh cache.
@@ -165,7 +163,7 @@ class PersistentMap<K, V, E, out EK>(
      * Removes the mapping for the specified key from this map and underlying storage if present.
      */
     override fun remove(key: K): V? {
-        val result = cache.get(key).orElse(null)
+        val result = cache.get(key)!!.orElse(null)
         cache.invalidate(key)
         return result
     }
@@ -253,7 +251,7 @@ class PersistentMap<K, V, E, out EK>(
     override fun put(key: K, value: V): V? {
         val old = cache.get(key)
         addWithDuplicatesReplaced(key, value)
-        return old.orElse(null)
+        return old!!.orElse(null)
     }
 
     fun load() {
diff --git a/tools/explorer/src/main/kotlin/net/corda/explorer/identicon/IdenticonRenderer.kt b/tools/explorer/src/main/kotlin/net/corda/explorer/identicon/IdenticonRenderer.kt
index 74f6998f93..5ec79549e8 100644
--- a/tools/explorer/src/main/kotlin/net/corda/explorer/identicon/IdenticonRenderer.kt
+++ b/tools/explorer/src/main/kotlin/net/corda/explorer/identicon/IdenticonRenderer.kt
@@ -1,8 +1,8 @@
 package net.corda.explorer.identicon
 
+import com.github.benmanes.caffeine.cache.CacheLoader
+import com.github.benmanes.caffeine.cache.Caffeine
 import com.google.common.base.Splitter
-import com.google.common.cache.CacheBuilder
-import com.google.common.cache.CacheLoader
 import javafx.scene.SnapshotParameters
 import javafx.scene.canvas.Canvas
 import javafx.scene.canvas.GraphicsContext
@@ -75,7 +75,7 @@ object IdenticonRenderer {
 
     private val renderingSize = 30.0
 
-    private val cache = CacheBuilder.newBuilder().build(CacheLoader.from<SecureHash, Image> { key ->
+    private val cache = Caffeine.newBuilder().build(CacheLoader<SecureHash, Image> { key ->
         key?.let { render(key.hashCode(), renderingSize) }
     })
 
@@ -92,7 +92,7 @@ object IdenticonRenderer {
     }
 
     fun getIdenticon(hash: SecureHash): Image {
-        return cache.get(hash)
+        return cache.get(hash)!!
     }
 
     /**