docs: update dao

dao/src/main/java/com/iluwatar/dao/CustomException.java

@@ -24,20 +24,16 @@
  */
 package com.iluwatar.dao;
 
+import java.io.Serial;
+
 /**
  * Custom exception.
  */
 public class CustomException extends Exception {
 
+  @Serial
   private static final long serialVersionUID = 1L;
 
-  public CustomException() {
-  }
-
-  public CustomException(String message) {
-    super(message);
-  }
-
   public CustomException(String message, Throwable cause) {
     super(message, cause);
   }

dao/src/test/java/com/iluwatar/dao/AppTest.java

@@ -35,7 +35,6 @@ class AppTest {
 
   /**
    * Issue: Add at least one assertion to this test case.
-   *
    * Solution: Inserted assertion to check whether the execution of the main method in {@link App#main(String[])}
    * throws an exception.
    */

dao/src/test/java/com/iluwatar/dao/DbCustomerDaoTest.java

@@ -87,7 +87,7 @@ class DbCustomerDaoTest {
     }
 
     /**
-     * Represents the scenario when DAO operations are being performed on a non existing customer.
+     * Represents the scenario when DAO operations are being performed on a non-existing customer.
      */
     @Nested
     class NonExistingCustomer {
@@ -206,39 +206,29 @@ class DbCustomerDaoTest {
 
     @Test
     void addingACustomerFailsWithExceptionAsFeedbackToClient() {
-      assertThrows(Exception.class, () -> {
-        dao.add(new Customer(2, "Bernard", "Montgomery"));
-      });
+      assertThrows(Exception.class, () -> dao.add(new Customer(2, "Bernard", "Montgomery")));
     }
 
     @Test
     void deletingACustomerFailsWithExceptionAsFeedbackToTheClient() {
-      assertThrows(Exception.class, () -> {
-        dao.delete(existingCustomer);
-      });
+      assertThrows(Exception.class, () -> dao.delete(existingCustomer));
     }
 
     @Test
     void updatingACustomerFailsWithFeedbackToTheClient() {
       final var newFirstname = "Bernard";
       final var newLastname = "Montgomery";
-      assertThrows(Exception.class, () -> {
-        dao.update(new Customer(existingCustomer.getId(), newFirstname, newLastname));
-      });
+      assertThrows(Exception.class, () -> dao.update(new Customer(existingCustomer.getId(), newFirstname, newLastname)));
     }
 
     @Test
     void retrievingACustomerByIdFailsWithExceptionAsFeedbackToClient() {
-      assertThrows(Exception.class, () -> {
-        dao.getById(existingCustomer.getId());
-      });
+      assertThrows(Exception.class, () -> dao.getById(existingCustomer.getId()));
     }
 
     @Test
     void retrievingAllCustomersFailsWithExceptionAsFeedbackToClient() {
-      assertThrows(Exception.class, () -> {
-        dao.getAll();
-      });
+      assertThrows(Exception.class, () -> dao.getAll());
     }
 
   }

dao/src/test/java/com/iluwatar/dao/InMemoryCustomerDaoTest.java

@@ -48,7 +48,7 @@ class InMemoryCustomerDaoTest {
   }
 
   /**
-   * Represents the scenario when the DAO operations are being performed on a non existent
+   * Represents the scenario when the DAO operations are being performed on a non-existent
    * customer.
    */
   @Nested
@@ -78,7 +78,7 @@ class InMemoryCustomerDaoTest {
     }
 
     @Test
-    void updationShouldBeFailureAndNotAffectExistingCustomers() throws Exception {
+    void updateShouldBeFailureAndNotAffectExistingCustomers() {
       final var nonExistingId = getNonExistingCustomerId();
       final var newFirstname = "Douglas";
       final var newLastname = "MacArthur";