diff --git a/nitrite/asciidoc.gradle b/nitrite/asciidoc.gradle
index d7297dc06..d2adffd80 100644
--- a/nitrite/asciidoc.gradle
+++ b/nitrite/asciidoc.gradle
@@ -52,6 +52,7 @@ javadoc {
     options.docletpath = configurations.asciidoclet.files as List
     options.doclet = 'org.asciidoctor.Asciidoclet'
     options.overview = "$generatedSources/overview.adoc"
+    options.encoding = "UTF-8"
     options.addStringOption "-base-dir", "${projectDir}"
     options.addStringOption "doctitle", "${project.name.capitalize()} ${project.version} API"
     options.addStringOption "windowtitle", "${project.name.capitalize()} ${project.version} API"
diff --git a/nitrite/src/main/java/org/dizitart/no2/filters/ElementMatchFilter.java b/nitrite/src/main/java/org/dizitart/no2/filters/ElementMatchFilter.java
index 62dc5d39c..52bf30ede 100644
--- a/nitrite/src/main/java/org/dizitart/no2/filters/ElementMatchFilter.java
+++ b/nitrite/src/main/java/org/dizitart/no2/filters/ElementMatchFilter.java
@@ -73,7 +73,7 @@ public Set<NitriteId> apply(NitriteMap<NitriteId, Document> documentMap) {
 
             if (fieldValue.getClass().isArray()) {
                 int length = Array.getLength(fieldValue);
-                List list = new ArrayList();
+                List list = new ArrayList(length);
                 for (int i = 0; i < length; i++) {
                     Object item = Array.get(fieldValue, i);
                     list.add(item);
diff --git a/nitrite/src/main/java/org/dizitart/no2/internals/DataService.java b/nitrite/src/main/java/org/dizitart/no2/internals/DataService.java
index 8dd7a98eb..f0aa23cdd 100644
--- a/nitrite/src/main/java/org/dizitart/no2/internals/DataService.java
+++ b/nitrite/src/main/java/org/dizitart/no2/internals/DataService.java
@@ -59,10 +59,10 @@ class DataService {
     }
 
     WriteResultImpl insert(Document... documents) {
-        List<NitriteId> nitriteIdList = new ArrayList<>();
-        List<ChangedItem> changedItems = new ArrayList<>();
+        List<NitriteId> nitriteIdList = new ArrayList<>(documents.length);
+        List<ChangedItem> changedItems = new ArrayList<>(documents.length);
 
-        log.debug("Total " + documents.length + " document(s) to be inserted in " + name);
+        log.debug("Total {} document(s) to be inserted in {}", documents.length, name);
 
         for (Document document : documents) {
             NitriteId nitriteId = document.getId();
@@ -81,12 +81,12 @@ WriteResultImpl insert(Document... documents) {
 
             synchronized (lock) {
                 Document already = underlyingMap.putIfAbsent(nitriteId, document);
-                log.debug("Inserting document " + document + " in " + name);
+                log.debug("Inserting document {} in {}", document, name);
 
                 if (already != null) {
                     // rollback changes
                     underlyingMap.put(nitriteId, already);
-                    log.debug("Another document already exists with id " + nitriteId);
+                    log.debug("Another document already exists with id {}", nitriteId);
                     throw new UniqueConstraintException(errorMessage("id constraint violation, " +
                             "entry with same id already exists in " + name, UCE_CONSTRAINT_VIOLATED));
                 } else {
@@ -115,7 +115,7 @@ WriteResultImpl insert(Document... documents) {
         WriteResultImpl result = new WriteResultImpl();
         result.setNitriteIdList(nitriteIdList);
 
-        log.debug("Returning write result " + result + " for collection " + name);
+        log.debug("Returning write result {}  for collection {}", result, name);
         return result;
     }
 
@@ -129,7 +129,7 @@ WriteResultImpl update(Filter filter, Document update, UpdateOptions updateOptio
 
         WriteResultImpl writeResult = new WriteResultImpl();
         if (cursor == null || cursor.size() == 0) {
-            log.debug("No document found to update by the filter " + filter + " in " + name);
+            log.debug("No document found to update by the filter {}  in  {}", filter, name);
             if (updateOptions.isUpsert()) {
                 return insert(update);
             } else {
@@ -152,10 +152,9 @@ WriteResultImpl update(Filter filter, Document update, UpdateOptions updateOptio
                 return writeResult;
             }
 
-            log.debug("Filter " + filter + " found total " + cursor.size()
-                    + " document(s) to update with options " + updateOptions + " in " + name);
+            log.debug("Filter {} found total {} document(s) to update with options {} in {}", filter, cursor.size(), updateOptions, name);
 
-            List<ChangedItem> changedItems = new ArrayList<>();
+            List<ChangedItem> changedItems = new ArrayList<>(cursor.size());
             for(final Document document : cursor) {
                 if (document != null) {
                     NitriteId nitriteId = document.getId();
@@ -163,7 +162,7 @@ WriteResultImpl update(Filter filter, Document update, UpdateOptions updateOptio
                     synchronized (lock) {
                         Document oldDocument = new Document(document);
 
-                        log.debug("Document to update " + document + " in " + name);
+                        log.debug("Document to update {} in {}", document, name);
 
                         if (!REPLICATOR.contentEquals(update.getSource())) {
                             update.remove(DOC_SOURCE);
@@ -177,7 +176,7 @@ WriteResultImpl update(Filter filter, Document update, UpdateOptions updateOptio
                         }
 
                         underlyingMap.put(nitriteId, document);
-                        log.debug("Document " + document + " updated in " + name);
+                        log.debug("Document {} updated in {}", document, name);
 
                         // if 'update' only contains id value, affected count = 0
                         if (update.size() > 0) {
@@ -198,7 +197,7 @@ WriteResultImpl update(Filter filter, Document update, UpdateOptions updateOptio
             notify(ChangeType.UPDATE, changedItems);
         }
 
-        log.debug("Returning write result " + writeResult + " for collection " + name);
+        log.debug("Returning write result {} for collection {}", writeResult, name);
         return writeResult;
     }
 
@@ -212,14 +211,13 @@ WriteResultImpl remove(Filter filter, RemoveOptions removeOptions) {
 
         WriteResultImpl result = new WriteResultImpl();
         if (cursor == null) {
-            log.debug("No document found to remove by the filter " + filter + " in " + name);
+            log.debug("No document found to remove by the filter {} in {}", filter, name);
             return result;
         }
 
-        log.debug("Filter " + filter + " found total " + cursor.size()
-                + " document(s) to remove with options " + removeOptions + " from " + name);
+        log.debug("Filter {} found total {} document(s) to remove with options {} from {}", filter, cursor.size(), removeOptions, name);
 
-        List<ChangedItem> changedItems = new ArrayList<>();
+        List<ChangedItem> changedItems = new ArrayList<>(cursor.size());
 
         synchronized (lock) {
             for (Document document : cursor) {
@@ -231,7 +229,7 @@ WriteResultImpl remove(Filter filter, RemoveOptions removeOptions) {
                 removed.put(DOC_REVISION, rev + 1);
                 removed.put(DOC_MODIFIED, System.currentTimeMillis());
 
-                log.debug("Document removed " + removed + " from " + name);
+                log.debug("Document removed {} from {}", removed, name);
 
                 result.addToList(nitriteId);
 
@@ -250,7 +248,7 @@ WriteResultImpl remove(Filter filter, RemoveOptions removeOptions) {
 
         notify(ChangeType.REMOVE, changedItems);
 
-        log.debug("Returning write result " + result + " for collection " + name);
+        log.debug("Returning write result {} for collection {}", result, name);
         return result;
     }
 
@@ -259,7 +257,7 @@ Document getById(NitriteId nitriteId) {
     }
 
     private void notify(ChangeType action, Collection<ChangedItem> changedItems) {
-        log.debug("Notifying " + action + " event for items " + changedItems + " from " + name);
+        log.debug("Notifying {} event for items {} from {}", action, changedItems, name);
         if (eventBus != null) {
             ChangeInfo changeInfo = new ChangeInfo(action);
             changeInfo.setChangedItems(changedItems);
diff --git a/nitrite/src/main/java/org/dizitart/no2/internals/DefaultNitriteCollection.java b/nitrite/src/main/java/org/dizitart/no2/internals/DefaultNitriteCollection.java
index 493a8c117..f9113f208 100644
--- a/nitrite/src/main/java/org/dizitart/no2/internals/DefaultNitriteCollection.java
+++ b/nitrite/src/main/java/org/dizitart/no2/internals/DefaultNitriteCollection.java
@@ -50,8 +50,8 @@ class DefaultNitriteCollection implements NitriteCollection {
     private NitriteService nitriteService;
     private volatile boolean isDropped;
     private EventBus<ChangeInfo, ChangeListener> eventBus;
-    private String collectionName;
-    private NitriteContext nitriteContext;
+    private final String collectionName;
+    private final NitriteContext nitriteContext;
 
     DefaultNitriteCollection(NitriteMap<NitriteId, Document> nitriteMap, NitriteContext nitriteContext) {
         this.nitriteMap = nitriteMap;
diff --git a/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVMap.java b/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVMap.java
index 3b8eb8b0d..c07f15fff 100644
--- a/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVMap.java
+++ b/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVMap.java
@@ -33,8 +33,8 @@
  * @author Anindya Chatterjee.
  */
 class NitriteMVMap<Key, Value> implements NitriteMap<Key, Value> {
-    private MVMap<Key, Value> mvMap;
-    private NitriteStore nitriteStore;
+    private final MVMap<Key, Value> mvMap;
+    private final NitriteStore nitriteStore;
 
     NitriteMVMap(MVMap<Key, Value> mvMap, NitriteStore nitriteStore) {
         this.mvMap = mvMap;
diff --git a/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVStore.java b/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVStore.java
index 548bacf1b..e92d246d6 100644
--- a/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVStore.java
+++ b/nitrite/src/main/java/org/dizitart/no2/store/NitriteMVStore.java
@@ -33,7 +33,7 @@
  * @author Anindya Chatterjee.
  */
 public final class NitriteMVStore implements NitriteStore {
-    private MVStore mvStore;
+    private final MVStore mvStore;
 
     /**
      * Instantiates a new {@link NitriteMVStore}.
diff --git a/nitrite/src/main/java/org/dizitart/no2/tool/Importer.java b/nitrite/src/main/java/org/dizitart/no2/tool/Importer.java
index 20427d1bb..6ff95536b 100644
--- a/nitrite/src/main/java/org/dizitart/no2/tool/Importer.java
+++ b/nitrite/src/main/java/org/dizitart/no2/tool/Importer.java
@@ -80,8 +80,9 @@ public void importFrom(String file) {
      * @throws NitriteIOException  if there is any low-level I/O error.
      */
     public void importFrom(File file) {
-        try {
-            importFrom(new FileInputStream(file));
+
+        try(FileInputStream stream = new FileInputStream(file);) {
+            importFrom(stream);
         } catch (IOException ioe) {
             throw new NitriteIOException(
                     errorMessage("I/O error while reading content from file " + file,
diff --git a/potassium-nitrite/README.adoc b/potassium-nitrite/README.adoc
index 045bbf7d0..748db2cf8 100644
--- a/potassium-nitrite/README.adoc
+++ b/potassium-nitrite/README.adoc
@@ -54,6 +54,14 @@ val db = nitrite("userId", "password") {
     autoCompact = false
 }
 
+// for android context
+val db = nitrite {
+    file = File(applicationContext.filesDir, fileName)
+    autoCommitBufferSize = 2048
+    compress = true
+    autoCompact = false
+}
+
 --
 
 *Collection / Repository*
diff --git a/potassium-nitrite/src/test/kotlin/org/dizitart/kno2/ImportExportTest.kt b/potassium-nitrite/src/test/kotlin/org/dizitart/kno2/ImportExportTest.kt
index 79745b8b3..59a6c175a 100644
--- a/potassium-nitrite/src/test/kotlin/org/dizitart/kno2/ImportExportTest.kt
+++ b/potassium-nitrite/src/test/kotlin/org/dizitart/kno2/ImportExportTest.kt
@@ -38,7 +38,7 @@ class ImportExportTest : BaseExternalTest() {
     @Test
     fun testImportExport() {
         schemaFile = (System.getProperty("java.io.tmpdir") + File.separator
-            + "nitrite" + File.separator + "schema.json")
+            + "kno2" + File.separator + "schema.json")
 
         val random = Random()
         for (i in 0..4) {