refactor: remove code smell java:S5786 (#2159)

https://sonarcloud.io/organizations/iluwatar/rules?open=java%3AS5786&rule_key=java%3AS5786

circuit-breaker/src/test/java/com/iluwatar/circuitbreaker/AppTest.java

@@ -34,7 +34,7 @@ import org.slf4j.LoggerFactory;
 /**
  * App Test showing usage of circuit breaker.
  */
-public class AppTest {
+class AppTest {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(AppTest.class);
 
@@ -60,7 +60,7 @@ public class AppTest {
    * and retry time period of 2 seconds.
    */
   @BeforeEach
-  public void setupCircuitBreakers() {
+  void setupCircuitBreakers() {
     var delayedService = new DelayedRemoteService(System.nanoTime(), STARTUP_DELAY);
     //Set the circuit Breaker parameters
     delayedServiceCircuitBreaker = new DefaultCircuitBreaker(delayedService, 3000,
@@ -78,7 +78,7 @@ public class AppTest {
   }
 
   @Test
-  public void testFailure_OpenStateTransition() {
+  void testFailure_OpenStateTransition() {
     //Calling delayed service, which will be unhealthy till 4 seconds
     assertEquals("Delayed service is down", monitoringService.delayedServiceResponse());
     //As failure threshold is "1", the circuit breaker is changed to OPEN
@@ -93,7 +93,7 @@ public class AppTest {
   }
 
   @Test
-  public void testFailure_HalfOpenStateTransition() {
+  void testFailure_HalfOpenStateTransition() {
     //Calling delayed service, which will be unhealthy till 4 seconds
     assertEquals("Delayed service is down", monitoringService.delayedServiceResponse());
     //As failure threshold is "1", the circuit breaker is changed to OPEN
@@ -112,7 +112,7 @@ public class AppTest {
   }
 
   @Test
-  public void testRecovery_ClosedStateTransition() {
+  void testRecovery_ClosedStateTransition() {
     //Calling delayed service, which will be unhealthy till 4 seconds
     assertEquals("Delayed service is down", monitoringService.delayedServiceResponse());
     //As failure threshold is "1", the circuit breaker is changed to OPEN

circuit-breaker/src/test/java/com/iluwatar/circuitbreaker/DefaultCircuitBreakerTest.java

@@ -31,7 +31,7 @@ import org.junit.jupiter.api.Test;
 /**
  * Circuit Breaker test
  */
-public class DefaultCircuitBreakerTest {
+class DefaultCircuitBreakerTest {
 
   //long timeout, int failureThreshold, long retryTimePeriod
   @Test

circuit-breaker/src/test/java/com/iluwatar/circuitbreaker/DelayedRemoteServiceTest.java

@@ -53,7 +53,7 @@ class DelayedRemoteServiceTest {
    * @throws RemoteServiceException
    */
   @Test
-  public void testParameterizedConstructor() throws RemoteServiceException {
+  void testParameterizedConstructor() throws RemoteServiceException {
       var obj = new DelayedRemoteService(System.nanoTime()-2000*1000*1000,1);
       assertEquals("Delayed service is working",obj.call());
   }