diff --git a/core/src/main/resources/org/elasticsearch/bootstrap/security.policy b/core/src/main/resources/org/elasticsearch/bootstrap/security.policy
index f953123c7a4..4909959015b 100644
--- a/core/src/main/resources/org/elasticsearch/bootstrap/security.policy
+++ b/core/src/main/resources/org/elasticsearch/bootstrap/security.policy
@@ -33,7 +33,10 @@ grant codeBase "${codebase.securesm-1.0.jar}" {
 
 grant codeBase "${codebase.lucene-core-6.0.0-snapshot-bea235f.jar}" {
   // needed to allow MMapDirectory's "unmap hack" (die unmap hack, die)
+  // java 8 package
   permission java.lang.RuntimePermission "accessClassInPackage.sun.misc";
+  // java 9 "package"
+  permission java.lang.RuntimePermission "accessClassInPackage.jdk.internal.ref";
   permission java.lang.reflect.ReflectPermission "suppressAccessChecks";
   // NOTE: also needed for RAMUsageEstimator size calculations
   permission java.lang.RuntimePermission "accessDeclaredMembers";
diff --git a/core/src/test/java/org/elasticsearch/cluster/routing/PrimaryAllocationIT.java b/core/src/test/java/org/elasticsearch/cluster/routing/PrimaryAllocationIT.java
index d911a1175c7..94336d23623 100644
--- a/core/src/test/java/org/elasticsearch/cluster/routing/PrimaryAllocationIT.java
+++ b/core/src/test/java/org/elasticsearch/cluster/routing/PrimaryAllocationIT.java
@@ -109,7 +109,12 @@ public class PrimaryAllocationIT extends ESIntegTestCase {
         logger.info("--> check that old primary shard does not get promoted to primary again");
         // kick reroute and wait for all shard states to be fetched
         client(master).admin().cluster().prepareReroute().get();
-        assertBusy(() -> assertThat(internalCluster().getInstance(GatewayAllocator.class, master).getNumberOfInFlightFetch(), equalTo(0)));
+        assertBusy(new Runnable() { 
+            @Override
+            public void run() {
+                assertThat(internalCluster().getInstance(GatewayAllocator.class, master).getNumberOfInFlightFetch(), equalTo(0));
+            }
+        });
         // kick reroute a second time and check that all shards are unassigned
         assertThat(client(master).admin().cluster().prepareReroute().get().getState().getRoutingNodes().unassigned().size(), equalTo(2));
     }
diff --git a/core/src/test/java/org/elasticsearch/common/lucene/LuceneTests.java b/core/src/test/java/org/elasticsearch/common/lucene/LuceneTests.java
index 8f8aea578de..8df6f5c78cc 100644
--- a/core/src/test/java/org/elasticsearch/common/lucene/LuceneTests.java
+++ b/core/src/test/java/org/elasticsearch/common/lucene/LuceneTests.java
@@ -364,6 +364,6 @@ public class LuceneTests extends ESTestCase {
      */
     public void testMMapHackSupported() throws Exception {
         // add assume's here if needed for certain platforms, but we should know if it does not work.
-        assertTrue(MMapDirectory.UNMAP_SUPPORTED);
+        assertTrue("MMapDirectory does not support unmapping: " + MMapDirectory.UNMAP_NOT_SUPPORTED_REASON, MMapDirectory.UNMAP_SUPPORTED);
     }
 }