diff --git a/core/src/test/java/org/elasticsearch/cluster/ClusterModuleTests.java b/core/src/test/java/org/elasticsearch/cluster/ClusterModuleTests.java
index 7ec086d4d68..81acd138d26 100644
--- a/core/src/test/java/org/elasticsearch/cluster/ClusterModuleTests.java
+++ b/core/src/test/java/org/elasticsearch/cluster/ClusterModuleTests.java
@@ -216,28 +216,35 @@ public class ClusterModuleTests extends ModuleTestCase {
         assertTrue(customSuppliers.containsKey(RestoreInProgress.TYPE));
         assertTrue(customSuppliers.containsKey("foo"));
 
-
-        IllegalStateException ise = expectThrows(IllegalStateException.class,
-            () -> ClusterModule.getClusterStateCustomSuppliers(Collections.singletonList(new ClusterPlugin() {
-            @Override
-            public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-                return Collections.singletonMap(SnapshotsInProgress.TYPE, () -> null);
-            }
-        })));
-        assertEquals(ise.getMessage(), "custom supplier key [snapshots] is registered more than once");
-
-        ise = expectThrows(IllegalStateException.class,
-            () -> ClusterModule.getClusterStateCustomSuppliers(Arrays.asList(new ClusterPlugin() {
-            @Override
-            public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-                return Collections.singletonMap("foo", () -> null);
-            }
-        }, new ClusterPlugin() {
-            @Override
-            public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
-                return Collections.singletonMap("foo", () -> null);
-            }
-        })));
-        assertEquals(ise.getMessage(), "custom supplier key [foo] is registered more than once");
+        {
+            // Eclipse Neon 2 didn't compile the plugins definition inside the lambda expression,
+            // probably due to https://bugs.eclipse.org/bugs/show_bug.cgi?id=511750, which is
+            // fixed in Eclipse Oxygon. Pulled out the plugins definition to make it work in older versions
+            List<ClusterPlugin> plugins = Collections.singletonList(new ClusterPlugin() {
+                @Override
+                public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
+                    return Collections.singletonMap(SnapshotsInProgress.TYPE, () -> null);
+                }
+            });
+            IllegalStateException ise = expectThrows(IllegalStateException.class,
+                    () -> ClusterModule.getClusterStateCustomSuppliers(plugins));
+            assertEquals(ise.getMessage(), "custom supplier key [snapshots] is registered more than once");
+        }
+        {
+            List<ClusterPlugin> plugins = Arrays.asList(new ClusterPlugin() {
+                @Override
+                public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
+                    return Collections.singletonMap("foo", () -> null);
+                }
+            }, new ClusterPlugin() {
+                @Override
+                public Map<String, Supplier<ClusterState.Custom>> getInitialClusterStateCustomSupplier() {
+                    return Collections.singletonMap("foo", () -> null);
+                }
+            });
+            IllegalStateException ise = expectThrows(IllegalStateException.class,
+                    () -> ClusterModule.getClusterStateCustomSuppliers(plugins));
+            assertEquals(ise.getMessage(), "custom supplier key [foo] is registered more than once");
+        }
     }
 }