diff --git a/.idea/compiler.xml b/.idea/compiler.xml
index 83b640e02c..652807fef9 100644
--- a/.idea/compiler.xml
+++ b/.idea/compiler.xml
@@ -14,6 +14,9 @@
       <module name="client_test" target="1.8" />
       <module name="corda-project_main" target="1.8" />
       <module name="corda-project_test" target="1.8" />
+      <module name="corda-webserver_integrationTest" target="1.8" />
+      <module name="corda-webserver_main" target="1.8" />
+      <module name="corda-webserver_test" target="1.8" />
       <module name="cordform-common_main" target="1.8" />
       <module name="cordform-common_test" target="1.8" />
       <module name="core_main" target="1.8" />
@@ -96,6 +99,8 @@
       <module name="verifier_test" target="1.8" />
       <module name="webcapsule_main" target="1.6" />
       <module name="webcapsule_test" target="1.6" />
+      <module name="webserver-webcapsule_main" target="1.6" />
+      <module name="webserver-webcapsule_test" target="1.6" />
       <module name="webserver_integrationTest" target="1.8" />
       <module name="webserver_main" target="1.8" />
       <module name="webserver_test" target="1.8" />
diff --git a/core/src/test/java/net/corda/core/flows/FlowsInJavaTest.java b/core/src/test/java/net/corda/core/flows/FlowsInJavaTest.java
index 5c6308c2d5..af255b2938 100644
--- a/core/src/test/java/net/corda/core/flows/FlowsInJavaTest.java
+++ b/core/src/test/java/net/corda/core/flows/FlowsInJavaTest.java
@@ -1,6 +1,7 @@
 package net.corda.core.flows;
 
 import co.paralleluniverse.fibers.Suspendable;
+import com.google.common.primitives.Primitives;
 import net.corda.core.identity.Party;
 import net.corda.testing.node.MockNetwork;
 import org.junit.After;
@@ -11,6 +12,7 @@ import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 
 import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.junit.Assert.fail;
 
 public class FlowsInJavaTest {
 
@@ -41,6 +43,30 @@ public class FlowsInJavaTest {
         assertThat(result.get()).isEqualTo("Hello");
     }
 
+    @Test
+    public void primitiveClassForReceiveType() throws InterruptedException {
+        // Using the primitive classes causes problems with the checkpointing so we use the wrapper classes and convert
+        // to the primitive class at callsite.
+        for (Class<?> receiveType : Primitives.allWrapperTypes()) {
+            primitiveReceiveTypeTest(receiveType);
+        }
+    }
+
+    private void primitiveReceiveTypeTest(Class<?> receiveType) throws InterruptedException {
+        PrimitiveReceiveFlow flow = new PrimitiveReceiveFlow(node2.getInfo().getLegalIdentity(), receiveType);
+        Future<?> result = node1.getServices().startFlow(flow).getResultFuture();
+        mockNet.runNetwork();
+        try {
+            result.get();
+            fail("ExecutionException should have been thrown");
+        } catch (ExecutionException e) {
+            assertThat(e.getCause())
+                    .isInstanceOf(IllegalArgumentException.class)
+                    .hasMessageContaining("primitive")
+                    .hasMessageContaining(receiveType.getName());
+        }
+    }
+
     @InitiatingFlow
     private static class SendInUnwrapFlow extends FlowLogic<String> {
         private final Party otherParty;
@@ -74,4 +100,21 @@ public class FlowsInJavaTest {
         }
     }
 
+    @InitiatingFlow
+    private static class PrimitiveReceiveFlow extends FlowLogic<Void> {
+        private final Party otherParty;
+        private final Class<?> receiveType;
+
+        private PrimitiveReceiveFlow(Party otherParty, Class<?> receiveType) {
+            this.otherParty = otherParty;
+            this.receiveType = receiveType;
+        }
+
+        @Suspendable
+        @Override
+        public Void call() throws FlowException {
+            receive(Primitives.unwrap(receiveType), otherParty);
+            return null;
+        }
+    }
 }
diff --git a/node/src/main/kotlin/net/corda/node/services/statemachine/FlowStateMachineImpl.kt b/node/src/main/kotlin/net/corda/node/services/statemachine/FlowStateMachineImpl.kt
index 977e1b416e..d8fa038ed2 100644
--- a/node/src/main/kotlin/net/corda/node/services/statemachine/FlowStateMachineImpl.kt
+++ b/node/src/main/kotlin/net/corda/node/services/statemachine/FlowStateMachineImpl.kt
@@ -1,9 +1,11 @@
 package net.corda.node.services.statemachine
 
 import co.paralleluniverse.fibers.Fiber
+import co.paralleluniverse.fibers.Fiber.parkAndSerialize
 import co.paralleluniverse.fibers.FiberScheduler
 import co.paralleluniverse.fibers.Suspendable
 import co.paralleluniverse.strands.Strand
+import com.google.common.primitives.Primitives
 import net.corda.core.concurrent.CordaFuture
 import net.corda.core.crypto.SecureHash
 import net.corda.core.crypto.random63BitValue
@@ -165,24 +167,26 @@ class FlowStateMachineImpl<R>(override val id: StateMachineRunId,
                                           payload: Any,
                                           sessionFlow: FlowLogic<*>,
                                           retrySend: Boolean): UntrustworthyData<T> {
+        requireNonPrimitive(receiveType)
         logger.debug { "sendAndReceive(${receiveType.name}, $otherParty, ${payload.toString().abbreviate(300)}) ..." }
         val session = getConfirmedSessionIfPresent(otherParty, sessionFlow)
-        val sessionData = if (session == null) {
+        val receivedSessionData: ReceivedSessionMessage<SessionData> = if (session == null) {
             val newSession = startNewSession(otherParty, sessionFlow, payload, waitForConfirmation = true, retryable = retrySend)
             // Only do a receive here as the session init has carried the payload
-            receiveInternal<SessionData>(newSession, receiveType)
+            receiveInternal(newSession, receiveType)
         } else {
             val sendData = createSessionData(session, payload)
-            sendAndReceiveInternal<SessionData>(session, sendData, receiveType)
+            sendAndReceiveInternal(session, sendData, receiveType)
         }
-        logger.debug { "Received ${sessionData.message.payload.toString().abbreviate(300)}" }
-        return sessionData.checkPayloadIs(receiveType)
+        logger.debug { "Received ${receivedSessionData.message.payload.toString().abbreviate(300)}" }
+        return receivedSessionData.checkPayloadIs(receiveType)
     }
 
     @Suspendable
     override fun <T : Any> receive(receiveType: Class<T>,
                                    otherParty: Party,
                                    sessionFlow: FlowLogic<*>): UntrustworthyData<T> {
+        requireNonPrimitive(receiveType)
         logger.debug { "receive(${receiveType.name}, $otherParty) ..." }
         val session = getConfirmedSession(otherParty, sessionFlow)
         val sessionData = receiveInternal<SessionData>(session, receiveType)
@@ -190,6 +194,12 @@ class FlowStateMachineImpl<R>(override val id: StateMachineRunId,
         return sessionData.checkPayloadIs(receiveType)
     }
 
+    private fun requireNonPrimitive(receiveType: Class<*>) {
+        require(!receiveType.isPrimitive) {
+            "Use the wrapper type ${Primitives.wrap(receiveType).name} instead of the primitive $receiveType.class"
+        }
+    }
+
     @Suspendable
     override fun send(otherParty: Party, payload: Any, sessionFlow: FlowLogic<*>) {
         logger.debug { "send($otherParty, ${payload.toString().abbreviate(300)})" }