diff --git a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/ForkJoinStateMachineConfiguration.java b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/ForkJoinStateMachineConfiguration.java
index 3a3e632c51..55e1397823 100644
--- a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/ForkJoinStateMachineConfiguration.java
+++ b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/ForkJoinStateMachineConfiguration.java
@@ -64,11 +64,11 @@ public class ForkJoinStateMachineConfiguration extends StateMachineConfigurerAda
 
     @Bean
     public Guard<String, String> mediumGuard() {
-        return (ctx) -> false;
+        return ctx -> false;
     }
 
     @Bean
     public Guard<String, String> highGuard() {
-        return (ctx) -> false;
+        return ctx -> false;
     }
 }
\ No newline at end of file
diff --git a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/JunctionStateMachineConfiguration.java b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/JunctionStateMachineConfiguration.java
index 2f48a9dbb5..21b37381df 100644
--- a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/JunctionStateMachineConfiguration.java
+++ b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/JunctionStateMachineConfiguration.java
@@ -50,11 +50,11 @@ public class JunctionStateMachineConfiguration extends StateMachineConfigurerAda
 
     @Bean
     public Guard<String, String> mediumGuard() {
-        return (ctx) -> false;
+        return ctx -> false;
     }
 
     @Bean
     public Guard<String, String> highGuard() {
-        return (ctx) -> false;
+        return ctx -> false;
     }
 }
\ No newline at end of file
diff --git a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/SimpleStateMachineConfiguration.java b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/SimpleStateMachineConfiguration.java
index d1b1ce001c..0c392c2c35 100644
--- a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/SimpleStateMachineConfiguration.java
+++ b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/SimpleStateMachineConfiguration.java
@@ -18,7 +18,7 @@ import java.util.logging.Logger;
 @EnableStateMachine
 public class SimpleStateMachineConfiguration extends StateMachineConfigurerAdapter<String, String> {
 
-    public static final Logger LOGGER = Logger.getLogger(SimpleStateMachineConfiguration.class.getName());
+    private static final Logger LOGGER = Logger.getLogger(SimpleStateMachineConfiguration.class.getName());
 
     @Override
     public void configure(StateMachineConfigurationConfigurer<String, String> config) throws Exception {
@@ -80,7 +80,7 @@ public class SimpleStateMachineConfiguration extends StateMachineConfigurerAdapt
 
     @Bean
     public Guard<String, String> simpleGuard() {
-        return (ctx) -> {
+        return ctx -> {
             int approvalCount = (int) ctx
               .getExtendedState()
               .getVariables()
diff --git a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/StateMachineListener.java b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/StateMachineListener.java
index 47a274404e..09e8946810 100644
--- a/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/StateMachineListener.java
+++ b/spring-state-machine/src/main/java/com/baeldung/spring/statemachine/config/StateMachineListener.java
@@ -7,10 +7,10 @@ import java.util.logging.Logger;
 
 public class StateMachineListener extends StateMachineListenerAdapter {
 
-    public static final Logger LOGGER = Logger.getLogger(StateMachineListener.class.getName());
+    private static final Logger LOGGER = Logger.getLogger(StateMachineListener.class.getName());
 
     @Override
     public void stateChanged(State from, State to) {
-        LOGGER.info(String.format("Transitioned from %s to %s%n", from == null ? "none" : from.getId(), to.getId()));
+        LOGGER.info(() -> String.format("Transitioned from %s to %s%n", from == null ? "none" : from.getId(), to.getId()));
     }
 }
diff --git a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/ForkJoinStateMachineIntegrationTest.java b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/ForkJoinStateMachineIntegrationTest.java
index b34d5c47c6..66acad901c 100644
--- a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/ForkJoinStateMachineIntegrationTest.java
+++ b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/ForkJoinStateMachineIntegrationTest.java
@@ -1,18 +1,15 @@
 package com.baeldung.spring.statemachine;
 
 import com.baeldung.spring.statemachine.config.ForkJoinStateMachineConfiguration;
-import com.baeldung.spring.statemachine.config.JunctionStateMachineConfiguration;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
-import javax.annotation.Resource;
 import java.util.Arrays;
 
 import static org.junit.Assert.assertEquals;
diff --git a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/HierarchicalStateMachineIntegrationTest.java b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/HierarchicalStateMachineIntegrationTest.java
index 3d7c0be828..00a9c9a08c 100644
--- a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/HierarchicalStateMachineIntegrationTest.java
+++ b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/HierarchicalStateMachineIntegrationTest.java
@@ -1,18 +1,15 @@
 package com.baeldung.spring.statemachine;
 
 import com.baeldung.spring.statemachine.config.HierarchicalStateMachineConfiguration;
-import com.baeldung.spring.statemachine.config.JunctionStateMachineConfiguration;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
-import javax.annotation.Resource;
 import java.util.Arrays;
 
 import static org.junit.Assert.assertEquals;
diff --git a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/JunctionStateMachineIntegrationTest.java b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/JunctionStateMachineIntegrationTest.java
index 93de23fad3..f0ee757522 100644
--- a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/JunctionStateMachineIntegrationTest.java
+++ b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/JunctionStateMachineIntegrationTest.java
@@ -1,20 +1,16 @@
 package com.baeldung.spring.statemachine;
 
 import com.baeldung.spring.statemachine.config.JunctionStateMachineConfiguration;
-import com.baeldung.spring.statemachine.config.SimpleEnumStateMachineConfiguration;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
-import javax.annotation.Resource;
-
 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration(classes = JunctionStateMachineConfiguration.class)
 public class JunctionStateMachineIntegrationTest {
diff --git a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateEnumMachineIntegrationTest.java b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateEnumMachineIntegrationTest.java
index 9074ece001..d345cd0dfc 100644
--- a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateEnumMachineIntegrationTest.java
+++ b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateEnumMachineIntegrationTest.java
@@ -3,19 +3,15 @@ package com.baeldung.spring.statemachine;
 import com.baeldung.spring.statemachine.applicationreview.ApplicationReviewEvents;
 import com.baeldung.spring.statemachine.applicationreview.ApplicationReviewStates;
 import com.baeldung.spring.statemachine.config.SimpleEnumStateMachineConfiguration;
-import com.baeldung.spring.statemachine.config.SimpleStateMachineConfiguration;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 
-import javax.annotation.Resource;
-
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
diff --git a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineBuilderIntegrationTest.java b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineBuilderIntegrationTest.java
index c1de8b8958..e5431d9d83 100644
--- a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineBuilderIntegrationTest.java
+++ b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineBuilderIntegrationTest.java
@@ -1,11 +1,11 @@
 package com.baeldung.spring.statemachine;
 
-import static org.junit.Assert.assertEquals;
-
 import org.junit.Test;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.config.StateMachineBuilder;
 
+import static org.junit.Assert.assertEquals;
+
 public class StateMachineBuilderIntegrationTest {
 
     @Test
diff --git a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineIntegrationTest.java b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineIntegrationTest.java
index 25df7c8cd3..aab07225a3 100644
--- a/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineIntegrationTest.java
+++ b/spring-state-machine/src/test/java/com/baeldung/spring/statemachine/StateMachineIntegrationTest.java
@@ -1,22 +1,17 @@
 package com.baeldung.spring.statemachine;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
+import com.baeldung.spring.statemachine.config.SimpleStateMachineConfiguration;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.statemachine.StateMachine;
-
-import com.baeldung.spring.statemachine.config.SimpleStateMachineConfiguration;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
-import org.springframework.test.context.junit4.SpringRunner;
 
-import javax.annotation.Resource;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 @RunWith(SpringJUnit4ClassRunner.class)
 @ContextConfiguration(classes = SimpleStateMachineConfiguration.class)
@@ -42,7 +37,7 @@ public class StateMachineIntegrationTest {
     }
 
     @Test
-    public void whenSimpleStringMachineActionState_thenActionExecuted() throws InterruptedException {
+    public void whenSimpleStringMachineActionState_thenActionExecuted() {
 
         stateMachine.sendEvent("E3");
         assertEquals("S3", stateMachine.getState().getId());