How to enable second level cache in Hibernate

Question

I need some pojo objects across my application so I want to know how to enable Second Level Cache. Until now by default First Level cache is enabled, I would also like to know what advantages and disadvantages of Second Level cache there are.

Answer 1

This is what you need to do:

1. Set the following Hibernate properties:

    <property name="hibernate.cache.use_second_level_cache">true</property>
    <property name="hibernate.cache.provider_class">ehcache</property>
   

2. Add an ehcache.xml file in your classpath, containing the cache configuration entries:

    <cache name="com.mycompany.MyEntity"
       maxElementsInMemory="50"
       eternal="true"
       overflowToDisk="false"
       timeToIdleSeconds="600"
       timeToLiveSeconds="600"
       diskPersistent="false"
       memoryStoreEvictionPolicy="LRU"       
    />
   

3. Define the Caching type for each entity:

    @Entity
    @Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
    public class MyEntity {
            ...
    }