Hibernate Caching

I found some useful information on internet about hibernate caching.I thought of sharing with everyone.
High-volume database traffic is a frequent cause of performance problems in Web applications. Hibernate is a high-performance, object/relational persistence and query service. In many cases, second-level caching can be just what Hibernate needs to realize its full performance-handling potential.

What is caching – Anything you can do to minimize traffic between a database and an application server is probably a good thing. In theory, an application ought to be able to maintain a cache containing data already loaded from the database, and only hit the database when information has to be updated. When the database is hit, the changes may invalidate the cache.

There are two different cache used in hibernate-
1. First Level cache – This is associated with session. This is default implemented in hibernate on a per-transaction basis. Hibernate uses this cache mainly to reduce the number of SQL queries it needs to generate within a given transaction. For example, if an object is modified several times within the same transaction, Hibernate will generate only one SQL UPDATE statement at the end of the transaction, containing all the modifications
2. Second level cache – This is associated with Session Factory object. It will survive Sessions and can be reused in new Session by same SessionFactory (which usually is one per application). By default the 2nd level cache is not enabled. This ’second-level’ cache exists as long as the session factory is alive. The second-level cache holds on to the ‘data’ for all properties and associations for individual entities that are marked to be cached. The second level cache is responsible for caching objects across sessions.

Cache Type
EHCache (Easy Hibernate Cache) — http://ehcache.sourceforge.net/
OSCache (Open Symphony) — http://www.opensymphony.com/oscache/
SwarmCache — http://swarmcache.sourceforge.net/
JBoss TreeCache — http://jboss.org/wiki/Wiki.jsp?page=JBossCache

• EHCache -s an open source widely used java distributed cache for general purpose caching, Java EE and light-weight containers. It features memory and disk stores, replicate by copy and invalidate, listeners, cache loaders, cache extensions, cache exception handlers, a gzip caching servlet filter, RESTful and SOAP APIs and much more. Ehcache is available under an Apache open source license and is actively developed, maintained and supported.It support read only, Non strict Read/write,Read/write caching.It does not support transactional caching architecture.
• OSCache – is “a Java framework” developed by OpenSymphony that makes it easy to cache content in Web applications.It is a caching solution that includes a JSP tag library and set of classes to perform fine grained dynamic caching of JSP content, servlet responses or arbitrary objects.It provides both in memory and persistent on disk caches.They can allow your site to have graceful error tolerance .It support read only, Non strict Read/write,Read/write caching.It does not support transactional schema caching architecture.
• SwarmCache is a simple cluster-based caching solution based on JavaGroups. It supports read-only or nonstrict read/write caching. This type of cache is appropriate for applications that typically have many more read operations than write operations.It support read only, Non strict Read/write caching.It does not support ,Read/write and transactional caching architecture.It is is a cluster-based caching.
• JBoss TreeCache – is a powerful replicated (synchronous or asynchronous) and transactional cache. Use this solution if you really need a true transaction-capable caching architecture.

Bean Scope

Bean scopes

When you create a bean definition what you are actually creating is a recipe for creating actual instances of the class defined by that bean definition. The idea that a bean definition is a recipe is important, because it means that, just like a class, you can potentially have many object instances created from a single recipe.

You can control not only the various dependencies and configuration values that are to be plugged into an object that is created from a particular bean definition, but also the scope of the objects created from a particular bean definition. This approach is very powerful and gives you the flexibility to choose the scope of the objects you create through configuration instead of having to 'bake in' the scope of an object at the Java class level. Beans can be defined to be deployed in one of a number of scopes: out of the box, the Spring Framework supports exactly five scopes (of which three are available only if you are using a web-awareApplicationContext).

The scopes supported out of the box are listed below:

Scope Description

singleton Scopes a single bean definition to a single object instance per Spring IoC container.

prototype Scopes a single bean definition to any number of object instances.

request Scopes a single bean definition to the lifecycle of a single HTTP request; that is each and every HTTP request will have its own instance of a bean created off the back of a single bean definition. Only valid in the context of a web-aware Spring ApplicationContext.

session Scopes a single bean definition to the lifecycle of a HTTP Session. Only valid in the context of a web-aware Spring ApplicationContext.

global session Scopes a single bean definition to the lifecycle of a global HTTP Session. Typically only valid when used in a portlet context. Only valid in the context of a web-aware Spring ApplicationContext.

reference

http://static.springsource.org/spring/docs/2.5.x/reference/beans.html#beans-factory-scopes

Strategies for starting a small business

• Expand your business horizons by reaching out to different customers
• Recognize your Unique Selling Point which is uniquely different from your competitors.
• Formulate an expert and professional team to execute your business plans
• Create Goodwill, impetus and proper management
• Recognize and safeguard your Intellectual Property
• Expand your business through various medium
• Look forward for tie-ups and meaningful collaborations with other companies
• Win the faith and reliability of your customers
• Do not neglect the importance of internet and create your business website
• Gain from your experience, deploy standard machinery and methodologies
• Provide money back assurance

Remember, business is all about proper approach, determination and dedication. Strike the perfect balance between vocation, family and leisure to go a long way.