fixed ArangoCollection.rename() thread safety

Author: rashtao

core/src/main/java/com/arangodb/internal/ArangoCollectionImpl.java

@@ -466,9 +466,7 @@ public CollectionPropertiesEntity changeProperties(final CollectionPropertiesOpt
 
     @Override
     public synchronized CollectionEntity rename(final String newName) {
-        final CollectionEntity result = executor.execute(renameRequest(newName), CollectionEntity.class);
-        name = result.getName();
-        return result;
+        return executor.execute(renameRequest(newName), CollectionEntity.class);
     }
 
     @Override

core/src/main/java/com/arangodb/internal/InternalArangoCollection.java

@@ -61,7 +61,7 @@ public abstract class InternalArangoCollection<A extends InternalArangoDB<E>, D
     private static final String TRANSACTION_ID = "x-arango-trx-id";
 
     private final D db;
-    protected volatile String name;
+    protected final String name;
 
     protected InternalArangoCollection(final D db, final String name) {
         super(db.executor, db.serde);

docs/v7_detailed_changes.md

@@ -342,6 +342,9 @@ The class `com.arangodb.DbName` has been removed. The database names can now be
 Support to unicode characters in data definition names (databases, collections, views, indexes) has been added, see
 [Support to unicode data definition names](v7_java.md#unicode-characters-in-data-definition-names).
 
+`com.arangodb.ArangoCollection.rename(String)` does not change anymore the collection name of the instance
+of `ArangoCollection` on which it is invoked. To interact with the renamed collection, a new instance
+of `ArangoCollection` with the new name must be created.
 
 ## API entities