Make the code build on Java 8

Gerrit v3.4 technically still supports Java 8 and the code
should be compatible with it.

Remove some avoidable Java 11 specific constructs and use the
equivalents in Java 8.

Change-Id: I0ca7e1d1a2b0bd3b7aa004e887c0e626b346d127

src/main/java/com/googlesource/gerrit/plugins/replication/pull/auth/PullReplicationGroupBackend.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/auth/PullReplicationGroupBackend.java b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/auth/PullReplicationGroupBackend.java
index ffd3c1f..c61d4d9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/auth/PullReplicationGroupBackend.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/auth/PullReplicationGroupBackend.java
@@ -28,7 +28,6 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.List;
 
 /** Backend to expose the pull-replication internal user group membership. */
 @Singleton
@@ -84,7 +83,7 @@
   @Override
   public Collection<GroupReference> suggest(String name, ProjectState project) {
     return NAME_PREFIX.contains(name.toLowerCase())
-        ? List.of(GroupReference.create(INTERNAL_GROUP_UUID, INTERNAL_GROUP_NAME))
+        ? Arrays.asList(GroupReference.create(INTERNAL_GROUP_UUID, INTERNAL_GROUP_NAME))
         : Collections.emptyList();
   }
 

src/main/java/com/googlesource/gerrit/plugins/replication/pull/fetch/InexistentRefTransportException.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/fetch/InexistentRefTransportException.java b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/fetch/InexistentRefTransportException.java
index 7c2e637..f97f648 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/fetch/InexistentRefTransportException.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/fetch/InexistentRefTransportException.java
@@ -40,8 +40,11 @@
   }
 
   public static Optional<TransportException> getOptionalPermanentFailure(TransportException e) {
-    return wrapException(JGIT_INEXISTENT_REF_PATTERN, e)
-        .or(() -> wrapException(CGIT_INEXISTENT_REF_PATTERN, e));
+    Optional<TransportException> jgitEx = wrapException(JGIT_INEXISTENT_REF_PATTERN, e);
+    if (jgitEx.isPresent()) {
+      return jgitEx;
+    }
+    return wrapException(CGIT_INEXISTENT_REF_PATTERN, e);
   }
 
   private static Optional<TransportException> wrapException(