diff --git a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapClassTest.java b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapClassTest.java
index f44d4ac6b8..dea194734f 100644
--- a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapClassTest.java
+++ b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapClassTest.java
@@ -15,11 +15,11 @@ import rx.Observable;
 
 public class AutomapClassTest {
 
-    ConnectionProvider connectionProvider = Connector.connectionProvider;
-    Database db = Database.from(connectionProvider);
+    private ConnectionProvider connectionProvider = Connector.connectionProvider;
+    private Database db = Database.from(connectionProvider);
 
-    Observable<Integer> create = null;
-    Observable<Integer> insert1, insert2 = null;
+    private Observable<Integer> create = null;
+    private Observable<Integer> insert1, insert2 = null;
 
     @Before
     public void setup() {
diff --git a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapInterfaceTest.java b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapInterfaceTest.java
index 79bae281eb..730e64fd34 100644
--- a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapInterfaceTest.java
+++ b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/AutomapInterfaceTest.java
@@ -15,11 +15,11 @@ import rx.Observable;
 
 public class AutomapInterfaceTest {
 
-    ConnectionProvider connectionProvider = Connector.connectionProvider;
-    Database db = Database.from(connectionProvider);
+    private ConnectionProvider connectionProvider = Connector.connectionProvider;
+    private Database db = Database.from(connectionProvider);
 
-    Observable<Integer> create = null;
-    Observable<Integer> insert1, insert2 = null;
+    private Observable<Integer> create = null;
+    private Observable<Integer> insert1, insert2 = null;
 
     @Before
     public void setup() {
diff --git a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/BasicQueryTypesTest.java b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/BasicQueryTypesTest.java
index 7677b2375d..034b3c1f50 100644
--- a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/BasicQueryTypesTest.java
+++ b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/BasicQueryTypesTest.java
@@ -15,10 +15,10 @@ import rx.Observable;
 
 public class BasicQueryTypesTest {
 
-    ConnectionProvider connectionProvider = Connector.connectionProvider;
-    Database db = Database.from(connectionProvider);
+    private ConnectionProvider connectionProvider = Connector.connectionProvider;
+    private Database db = Database.from(connectionProvider);
 
-    Observable<Integer> create, insert1, insert2, insert3, update, delete = null;
+    private Observable<Integer> create, insert1, insert2, insert3, update, delete = null;
 
     @Test
     public void whenCreateTableAndInsertRecords_thenCorrect() {
diff --git a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertBlobTest.java b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertBlobTest.java
index fb3018ede4..1ca82f81f3 100644
--- a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertBlobTest.java
+++ b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertBlobTest.java
@@ -18,13 +18,13 @@ import rx.Observable;
 
 public class InsertBlobTest {
 
-    ConnectionProvider connectionProvider = Connector.connectionProvider;
-    Database db = Database.from(connectionProvider);
+    private ConnectionProvider connectionProvider = Connector.connectionProvider;
+    private Database db = Database.from(connectionProvider);
 
-    String expectedDocument = null;
-    String actualDocument = null;
+    private String expectedDocument = null;
+    private String actualDocument = null;
 
-    Observable<Integer> create, insert = null;
+    private Observable<Integer> create, insert = null;
 
     @Before
     public void setup() throws IOException {
diff --git a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertClobTest.java b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertClobTest.java
index d29c2e3de2..0a685075f3 100644
--- a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertClobTest.java
+++ b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/InsertClobTest.java
@@ -17,13 +17,13 @@ import rx.Observable;
 
 public class InsertClobTest {
 
-    ConnectionProvider connectionProvider = Connector.connectionProvider;
-    Database db = Database.from(connectionProvider);
+    private ConnectionProvider connectionProvider = Connector.connectionProvider;
+    private Database db = Database.from(connectionProvider);
 
-    String expectedDocument = null;
-    String actualDocument = null;
+    private String expectedDocument = null;
+    private String actualDocument = null;
 
-    Observable<Integer> create, insert = null;
+    private Observable<Integer> create, insert = null;
 
     @Before
     public void setup() throws IOException {
diff --git a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/ReturnKeysTest.java b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/ReturnKeysTest.java
index 87604b6c5f..50c81afcc4 100644
--- a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/ReturnKeysTest.java
+++ b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/ReturnKeysTest.java
@@ -13,11 +13,11 @@ import rx.Observable;
 
 public class ReturnKeysTest {
 
-    Observable<Boolean> begin, commit = null;
-    Observable<Integer> createStatement, insertStatement, updateStatement = null;
+    private Observable<Boolean> begin = null;
+    private Observable<Integer> createStatement = null;
 
-    ConnectionProvider connectionProvider = Connector.connectionProvider;
-    Database db = Database.from(connectionProvider);
+    private ConnectionProvider connectionProvider = Connector.connectionProvider;
+    private Database db = Database.from(connectionProvider);
 
     @Before
     public void setup() {
diff --git a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/TransactionTest.java b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/TransactionTest.java
index 9603a11c46..b7a1bb5b79 100644
--- a/rxjava/src/test/java/com/baeldung/rxjava/jdbc/TransactionTest.java
+++ b/rxjava/src/test/java/com/baeldung/rxjava/jdbc/TransactionTest.java
@@ -12,11 +12,10 @@ import rx.Observable;
 
 public class TransactionTest {
 
-    Observable<Boolean> begin, commit = null;
-    Observable<Integer> createStatement, insertStatement, updateStatement = null;
+    private Observable<Integer> createStatement = null;
 
-    ConnectionProvider connectionProvider = Connector.connectionProvider;
-    Database db = Database.from(connectionProvider);
+    private ConnectionProvider connectionProvider = Connector.connectionProvider;
+    private Database db = Database.from(connectionProvider);
 
     @Test
     public void whenCommitTransaction_thenRecordUpdated() {