java spring hibernate interview questions

#Java spring hibernate interview questions how to#
#Java spring hibernate interview questions free#

An application can use many session object. The first level cache data will not be available to entire application.

#Java spring hibernate interview questions free#

It is given by Hibernate at free of cost. Session object holds the first level cache data. There are mainly two types of caching: first level cache and second level cache. Hibernate caching improves the performance of the application by pooling the object in the cache. What are the core interfaces of Hibernate ? After detached state, object comes to persistent state if you call lock() or update() method.

Detached: The object is in detached state if session is closed.

Persistent: The object is in persistent state if session is open, and you just saved the instance in the database or retrieved the instance from the database.

Transient: The object is in transient state if it is just created but has no primary key (identifier) and not associated with session.

What are the different states of a hibernate object ?

Public void trace(Object message)It prints messages with the level Level.TRACE. Public void warn(Object message)It prints messages with the level Level.WARN. Public void info(Object message)It prints messages with the level Level.INFO. Public void fatal(Object message)It prints messages with the level Level.FATAL. Public void error(Object message)It prints messages with the level Level.ERROR. Public void debug(Object message)It prints messages with the level Level.DEBUG. What are the logging methods available in log4j ? 1 Clear this HashMap and your are done! The file monitor won’t really help since you have a custom classloader. All resources will be re-read from disk on request. All you can do is access that map via reflection and call the clear method. A change won’t be visible unless you restart the context. The Tomcat Webapp Classloader caches every resource which has been loaded by it.

#Java spring hibernate interview questions how to#

How to recognize properties file changes without restarting Tomcat ? That means I can put some object into modelAndView using the addObject() method, and it will be added to the session if the name of the object will be the same as the name of the argument in ( 'thought' ) In this example I have declared just one session attribute with the name “ thought“. Confusing nature: Autowiring is less exact than explicit wiring, so if possible prefer using explicit wiring.Primitive data types: You cannot autowire simple properties such as primitives, Strings, and Classes.Overriding: You can still specify dependencies using and settings which will always override autowiring.Singleton means only one instance, but in spring it is one instance per one ApplicationContext. REST permits different data format such as Plain text, HTML, XML, JSON etc.Īutowiring is automatic finding of dependencies by spring. RESTful web services inherits security measures from the underlying transport.

REST requires less bandwidth and resource than SOAP.

SOAP requires more bandwidth and resource than REST. REST does not define too much standards like SOAP. SOAP defines standards to be strictly followed. JAX-RS is the java API for RESTful web services. JAX-WS is the java API for SOAP web services. SOAP uses services interfaces to expose the business logic. REST can use SOAP web services because it is a concept and can use any protocol like HTTP, SOAP. SOAP can’t use REST because it is a protocol. REST stands for REpresentational State Transfer. SOAP stands for Simple Object Access Protocol. What is the difference between SOAP and REST webservices ? No. I have used Hibernate 4.3 version and JPA 2.1 version. Minimum version of Java to use Spring 4 is Java 6 Spring 4.0 is the first version to fully support Java 8 features. Spring 3.0 made use of Java 5 improvements in language. What are the major features in different versions of Spring ? But now as spring is giving object created the whole control is now with Spring. The whole control of the empid object is with employee class. When we create an object lets say empid, in a class named employee. So this is called as dependency injection. So here the reference variable is the dependent object and the injection is being done. Previously we used to create an object with the help of new or newInstance keyword, but now in spring we just create the reference variable and spring will create an object (bean) for us and give it to the reference variable.