diff --git a/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBKeyValueStore.java b/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBKeyValueStore.java
index 30058c7..3ffaf9d 100644
--- a/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBKeyValueStore.java
+++ b/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBKeyValueStore.java
@@ -16,8 +16,8 @@
 
 import com.apple.foundationdb.KeyValue;
 import com.apple.foundationdb.LocalityUtil;
-import com.apple.foundationdb.async.CloseableAsyncIterator;
 import com.apple.foundationdb.async.AsyncIterator;
+import com.apple.foundationdb.async.CloseableAsyncIterator;
 import com.apple.foundationdb.directory.DirectorySubspace;
 import com.google.common.base.Preconditions;
 import org.janusgraph.diskstorage.BackendException;
@@ -75,11 +75,6 @@ private static FoundationDBTx getTransaction(StoreTransaction txh) {
 
     @Override
     public synchronized void close() throws BackendException {
-        try {
-            //if(isOpen) db.close();
-        } catch (Exception e) {
-            throw new PermanentBackendException(e);
-        }
         if (isOpen) manager.removeDatabase(this);
         isOpen = false;
     }
@@ -168,7 +163,7 @@ public RecordIterator<KeyValueEntry> getSliceAsync(KVQuery query, StoreTransacti
 
             return new FoundationDBRecordAsyncIterator(db, tx, rangeQuery, result, query.getKeySelector());
         } catch (Exception e) {
-            log.error("getSliceAsync db=%s, tx=%s with exception", name, txh, e);
+            log.error("getSliceAsync db={}, tx={} with exception", name, txh, e);
             throw new PermanentBackendException(e);
         }
     }
@@ -259,6 +254,9 @@ public void delete(StaticBuffer key, StoreTransaction txh) throws BackendExcepti
         }
     }
 
+    /* this method is not called within JanusGraph, it's used for bulk access in Spark jobs.
+    For more: Please check: {@link https://github.com/JanusGraph/janusgraph-foundationdb/pull/48#discussion_r498917927}
+     */
     public List<StaticBuffer> getBoundaryKeys() {
         List<StaticBuffer> keys = new ArrayList<>();
         try (CloseableAsyncIterator<byte[]> it = LocalityUtil.getBoundaryKeys(manager.db, db.range().begin, db.range().end)) {
@@ -275,4 +273,6 @@ public List<StaticBuffer> getBoundaryKeys() {
     static StaticBuffer getBuffer(byte[] entry) {
         return new StaticArrayBuffer(entry);
     }
+
+
 }
diff --git a/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBRangeQuery.java b/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBRangeQuery.java
index febb502..fe4acce 100644
--- a/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBRangeQuery.java
+++ b/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBRangeQuery.java
@@ -25,10 +25,10 @@
  */
 public class FoundationDBRangeQuery {
 
-    private KVQuery originalQuery;
+    private final KVQuery originalQuery;
     private KeySelector startKeySelector;
     private KeySelector endKeySelector;
-    private int limit;
+    private final int limit;
 
     public FoundationDBRangeQuery(Subspace db, KVQuery kvQuery) {
         originalQuery = kvQuery;
diff --git a/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBTx.java b/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBTx.java
index 159d676..f98f86e 100644
--- a/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBTx.java
+++ b/src/main/java/org/janusgraph/diskstorage/foundationdb/FoundationDBTx.java
@@ -52,8 +52,8 @@ public class FoundationDBTx extends AbstractStoreTransaction {
 
     private final Database db;
 
-    private List<Insert> inserts = Collections.synchronizedList(new ArrayList<>());
-    private List<byte[]> deletions = Collections.synchronizedList(new ArrayList<>());
+    private final List<Insert> inserts = Collections.synchronizedList(new ArrayList<>());
+    private final List<byte[]> deletions = Collections.synchronizedList(new ArrayList<>());
 
     private int maxRuns = 1;
 
@@ -61,10 +61,10 @@ public enum IsolationLevel {SERIALIZABLE, READ_COMMITTED_NO_WRITE, READ_COMMITTE
 
     private final IsolationLevel isolationLevel;
 
-    private AtomicInteger txCtr = new AtomicInteger(0);
+    private final AtomicInteger txCtr = new AtomicInteger(0);
 
-    private static AtomicInteger transLocalIdCounter = new AtomicInteger(0);
-    private int transactionId = 0;
+    private static final AtomicInteger transLocalIdCounter = new AtomicInteger(0);
+    private final int transactionId;
 
     public FoundationDBTx(Database db, Transaction t, BaseTransactionConfig config, IsolationLevel isolationLevel) {
         super(config);
@@ -149,7 +149,7 @@ public synchronized void rollback() throws BackendException {
 
 
     private void logFDBException(Throwable t) {
-        if (t != null && t instanceof FDBException) {
+        if (t instanceof FDBException) {
             FDBException fe = (FDBException) t;
             if (log.isDebugEnabled()) {
                 log.debug("Catch FDBException code= {}, isRetryable={}, isMaybeCommitted={}, "
@@ -449,8 +449,8 @@ public void clear(final byte[] key) {
 
 
     private class Insert {
-        private byte[] key;
-        private byte[] value;
+        private final byte[] key;
+        private final byte[] value;
 
         public Insert(final byte[] key, final byte[] value) {
             this.key = key;