Add application file and update entity in model

spring-boot-modules/spring-caching-2/src/main/java/com/baeldung/caching/twolevelcache/Customer.java

@@ -5,14 +5,18 @@ import lombok.Data;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 
+import javax.persistence.Entity;
+import javax.persistence.Id;
 import java.io.Serializable;
 
 @Data
+@Entity
 @AllArgsConstructor
 @NoArgsConstructor
 @Setter
 public class Customer implements Serializable {
 
+    @Id
     private String id;
 
     private String name;

spring-boot-modules/spring-caching-2/src/main/java/com/baeldung/caching/twolevelcache/TwoLevelCacheApplication.java

@@ -0,0 +1,14 @@
+package com.baeldung.caching.twolevelcache;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cache.annotation.EnableCaching;
+
+@SpringBootApplication
+@EnableCaching
+public class TwoLevelCacheApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(TwoLevelCacheApplication.class, args);
+    }
+}