Updated the code and test cases

core-java-modules/core-java-serialization/src/main/java/com/baeldung/serialization/Customer.java

@@ -0,0 +1,35 @@
+package com.baeldung.serialization;
+
+import java.io.Serializable;
+
+public class Customer implements Serializable {
+    private static final long serialVersionUID = 1L;
+
+    private long id;
+    private volatile String name;
+    private Address address;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Address getAddress() {
+        return address;
+    }
+
+    public void setAddress(Address address) {
+        this.address = address;
+    }
+}

core-java-modules/core-java-serialization/src/main/java/com/baeldung/util/MySerializationUtils.java

@@ -29,7 +29,7 @@ public class MySerializationUtils {
     public static boolean isSerializable(Class<?> it) {
         boolean serializable = it.isPrimitive() || it.isInterface() || Serializable.class.isAssignableFrom(it);
         if (!serializable) {
-            return serializable;
+            return false;
         }
         Field[] declaredFields = it.getDeclaredFields();
         for (Field field : declaredFields) {
@@ -37,7 +37,7 @@ public class MySerializationUtils {
                 continue;
             }
             Class<?> fieldType = field.getType();
-            return isSerializable(fieldType);
+            serializable = isSerializable(fieldType);
         }
         return serializable;
     }

core-java-modules/core-java-serialization/src/test/java/com/baeldung/serialization/SerializationUnitTest.java

@@ -107,5 +107,7 @@ public class SerializationUnitTest {
         assertFalse(MySerializationUtils.isSerializable(Address.class));
         assertTrue(MySerializationUtils.isSerializable(Person.class));
         assertTrue(MySerializationUtils.isSerializable(Integer.class));
+        assertFalse(MySerializationUtils.isSerializable(Customer.class));
+        assertTrue(MySerializationUtils.isSerializable(Employee.class));
     }
 }