docs: update gateway

gateway/src/main/java/com/iluwatar/gateway/ExternalServiceA.java

@@ -26,7 +26,6 @@ package com.iluwatar.gateway;
 
 
 import lombok.extern.slf4j.Slf4j;
-import org.slf4j.Logger;
 
 /**
 * ExternalServiceA is one of external services.
@@ -40,4 +39,3 @@ class ExternalServiceA implements Gateway {
     Thread.sleep(1000);
   }
 }
-

gateway/src/main/java/com/iluwatar/gateway/ExternalServiceC.java

@@ -39,7 +39,7 @@ class ExternalServiceC implements Gateway {
     Thread.sleep(1000);
   }
 
-  public void error() throws Exception {
+  public void error() {
     // Simulate an exception
     throw new RuntimeException("Service C encountered an error");
   }

gateway/src/test/java/com/iluwatar/gateway/ServiceFactoryTest.java

@@ -25,17 +25,17 @@
 package com.iluwatar.gateway;
 
 
-import org.junit.Before;
-import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicBoolean;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import org.junit.Before;
+import org.junit.Test;
 
 public class ServiceFactoryTest {
     private GatewayFactory gatewayFactory;
@@ -65,7 +65,7 @@ public class ServiceFactoryTest {
     @Test
     public void testGatewayFactoryRegistrationWithNonExistingKey() {
         Gateway nonExistingService = gatewayFactory.getGateway("NonExistingService");
-        assertEquals(null, nonExistingService);
+        assertNull(nonExistingService);
     }
 
     @Test
@@ -88,6 +88,6 @@ public class ServiceFactoryTest {
         }
 
         latch.await();
-        assertTrue("This should not fail", !failed.get());
+        assertFalse("This should not fail", failed.get());
     }
 }