Some minor changes to style and to sync with article code

core-java-8/src/main/java/com/baeldung/enums/Pizza.java

@@ -8,24 +8,24 @@ import java.util.stream.Collectors;
 public class Pizza {
 
     private static EnumSet<PizzaStatusEnum> deliveredPizzaStatuses =
-      EnumSet.of(PizzaStatusEnum.DELIVERED);
+            EnumSet.of(PizzaStatusEnum.DELIVERED);
 
     private PizzaStatusEnum status;
 
     public enum PizzaStatusEnum {
-        ORDERED (5){
+        ORDERED(5) {
             @Override
             public boolean isOrdered() {
                 return true;
             }
         },
-        READY (2){
+        READY(2) {
             @Override
             public boolean isReady() {
                 return true;
             }
         },
-        DELIVERED (0){
+        DELIVERED(0) {
             @Override
             public boolean isDelivered() {
                 return true;
@@ -34,16 +34,23 @@ public class Pizza {
 
         private int timeToDelivery;
 
-        public boolean isOrdered() {return false;}
+        public boolean isOrdered() {
+            return false;
+        }
 
-        public boolean isReady() {return false;}
+        public boolean isReady() {
+            return false;
+        }
+
+        public boolean isDelivered() {
+            return false;
+        }
 
-        public boolean isDelivered(){return  false;}
         public int getTimeToDelivery() {
             return timeToDelivery;
         }
 
-        private PizzaStatusEnum (int timeToDelivery) {
+        PizzaStatusEnum(int timeToDelivery) {
             this.timeToDelivery = timeToDelivery;
         }
     }
@@ -69,10 +76,9 @@ public class Pizza {
     }
 
     public static EnumMap<PizzaStatusEnum, List<Pizza>> groupPizzaByStatus(List<Pizza> pzList) {
-        EnumMap<PizzaStatusEnum, List<Pizza>> map = pzList.stream().collect(
-          Collectors.groupingBy(Pizza::getStatus,
-          () -> new EnumMap<PizzaStatusEnum, List<Pizza>>(PizzaStatusEnum.class), Collectors.toList()));
-        return map;
+        return pzList.stream().collect(
+                Collectors.groupingBy(Pizza::getStatus,
+                        () -> new EnumMap<>(PizzaStatusEnum.class), Collectors.toList()));
     }
 
     public void deliver() {
@@ -81,4 +87,5 @@ public class Pizza {
             this.setStatus(PizzaStatusEnum.DELIVERED);
         }
     }
+
 }

core-java-8/src/main/java/com/baeldung/enums/PizzaDeliverySystemConfiguration.java

@@ -2,9 +2,10 @@ package com.baeldung.enums;
 
 
 public enum PizzaDeliverySystemConfiguration {
-    INSTANCE ;
-    private PizzaDeliverySystemConfiguration() {
-        //Do the configuration initialization which
+    INSTANCE;
+
+    PizzaDeliverySystemConfiguration() {
+        // Do the configuration initialization which
         // involves overriding defaults like delivery strategy
     }
 

core-java-8/src/test/java/com/baeldung/enums/PizzaTest.java

@@ -10,6 +10,7 @@ import java.util.List;
 import static junit.framework.TestCase.assertTrue;
 
 public class PizzaTest {
+
     @Test
     public void givenPizaOrder_whenReady_thenDeliverable() {
         Pizza testPz = new Pizza();
@@ -19,7 +20,7 @@ public class PizzaTest {
 
     @Test
     public void givenPizaOrders_whenRetrievingUnDeliveredPzs_thenCorrectlyRetrieved() {
-        List<Pizza> pzList = new ArrayList<Pizza>();
+        List<Pizza> pzList = new ArrayList<>();
         Pizza pz1 = new Pizza();
         pz1.setStatus(Pizza.PizzaStatusEnum.DELIVERED);
 
@@ -44,7 +45,7 @@ public class PizzaTest {
     @Test
     public void givenPizaOrders_whenGroupByStatusCalled_thenCorrectlyGrouped() {
 
-        List<Pizza> pzList = new ArrayList<Pizza>();
+        List<Pizza> pzList = new ArrayList<>();
         Pizza pz1 = new Pizza();
         pz1.setStatus(Pizza.PizzaStatusEnum.DELIVERED);
 
@@ -75,4 +76,5 @@ public class PizzaTest {
         pz.deliver();
         assertTrue(pz.getStatus() == Pizza.PizzaStatusEnum.DELIVERED);
     }
+
 }