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Spring 3.x certification mock test

Questions very similar to originals with almost the same difficulty level. Majority questions are from most important sections at exam: container, testing, AOP, transactions. Only few from other sections like MVC, REST, JMX, JMS.

This is a 30 question practice test. 5 questions are free for you to try.

It is very reasonably priced at $1.99.

If you buy all there tests, you would save on paypal fees.

I am sure you would like the test. Jacek is looking for feedback and inputs to make the test better.

Here are way to add google + on your site.

1. Go to your webmaster console.  i am sure if you would like to add google+ on your site you would have a  account with google webmaster.

2. Go to +1 Metrics –> search impact on your left and click on it.

3. You would find see a heading Add +1 button on right. Click on that and it will lead you to a page which code generated like

<!– Place this tag in your head or just before your close body tag –>
<script type=”text/javascript” src=”https://apis.google.com/js/plusone.js”></script>

<!– Place this tag where you want the +1 button to render –>
<g:plusone></g:plusone>

4. Add that code on your site. If for some reasons this does not work as it dies work with jsp and jsf sites, add this
<!– Place this tag in your head or just before your close body tag –>
<script type=”text/javascript” src=”https://apis.google.com/js/plusone.js”></script>
<div data-size=”standard” data-count=”true” align=”left”></div>

Preview the page and + 1 button has been added to your  site

1. If it is a small project with few tables , I think there is no need for a full fledge ORM framework like hibernate. You can very well using Spring with JDBC and keep complexity to minimum.

But this is a classic mistake made by teams initially. You assume that the project will have only 3-4 tables and few updates and inserts, but as and when you gather requirements, dive deep into design , add more features, it starts to get bigger.

At later stage you wishes you had started with ORM framework else you might have to write all the inserts, updates and selects which is a huge waste of time ,considering all this can be configured easily by hibernate.

2. Performance : A lot is being talked about hibernate performance. We have used Spring and hibernate with one of the biggest deployment in clinical applications and I can tell you, I have not seen any issues or so because of hibernate.

Yes we had to fix the hqls at few places but that is a normal tuning process.

3. Hibernate is slow because it uses run time reflection:  People who had faced performance issues with reflection in early ears were skeptical about hibernate’s use of reflection. But not anymore. You should not worry about performance loss due to reflection. From hibernate’s doc

Modern JVMs implement reflection extremely efficiently and the overhead is minimal compared to the cost of disk access or IPC. Developers from other traditions (eg. Smalltalk) have always relied upon reflection to do things that C/C++ needs code-generation for.

In the very latest versions of Hibernate, “reflection” is optimized via the CGLIB runtime bytecode generation library. This means that “reflected” property get / set calls no longer carry the overhead of the Java reflection API and are actually just normal method calls. This results in a (very) small performance gain.

You can always hancode sql’s at places where you think it is going to be complex scenarios and a native sql would perform much better. But this is required rarely , so this is an exception , not a rule.

4.  Composite mapping is complex : If you do not understand it , yes it is complex . But this will not be a disadvantage. We have talked about this here mapping composite keys in hibernate.

3. Everything is returned as object : Yes that is true and even if you would like to get an id or name, you would write the hql and get an object which has the complete data set. This is anyways not bad because while designing methods, you will have coarse grained objects which well be returned. I would not prefer to return String or int from my methods.

Our application was developed using Spring framework 2.5 , spring webflow and hibernate 3.0. We had Oracle application server (not the oracle weblogic ) and oracle database 10g

Caching : Second level caching was done using ehcache. The caching strategy was read-only which is the simplest and best-performing cache strategy

Stored Procedures : Procs were used at couple of places. These procs had business logic and were communicating with another database through DB Link.

Native queries : We did not use any native queries.

We have used Spring and hibernate with one of the biggest deployment in applications and I can tell you, I have not seen any issues or so because of hibernate.

Yes we had to fix the hqls at few places but that is a normal tuning process.

I cannot share much details here neither the performance statistics but will be happy to answer your questions.

Make sure that database statistics is upto-date. As this is one of the factor which can influence explain plan. We can gather statistics by executing following command:

EXEC DBMS_STATS.gather_schema_stats(‘TDWDBA’);

Where TDWDBA is the schema name.

Surefire runs unit tests during build phase, not integration tests which are executed during package phase. But you can include integration tests also to be run

Below is the configuration for surefire plugin in your pom.xml

<profile>
<id>itest</id>
<build>
<plugins>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>${maven.surefire.report.version}</version>
<configuration>
<includes>
<include>**/*IntTest.java</include>
<include>**/*IntTests.java</include>
</includes>
</configuration>
</plugin>

</plugins>
</build>
</profile>

Take a look at this code :

Session hSession = this.getCurrentSession();

hSession.beginTransaction();
User u = (User)hSession.get(User.class, 8);
u.setLoginName(“skillguru”);
u.setPassword(“forgetmenot”);
hibernateSession.getTransaction().commit();

session.get() makes a hit to the database to get the data if the obejct does not
exist in the application.
Session.load gets the proxy for the instance, hence saving a database trip.But if there was no such object in the database then the method session.load() throws an exception whereas session.get() returns null.
Both the methods will return the instance or a proxy for the instance, if the instance or
proxy is already associated with the session.Only difference is that the session.load()
will throw an exception if the persistent entity does not exist in the database

Let us say you have database user name , password etc configured in jdbc.properties and would like to inject the values at run time.

Here is what will go in applicationContext.xml

<bean id=”dataSource” destroy-method=”close”>
<property name=”driverClass” value=”${jdbc.driverClass}”/>
<property name=”jdbcUrl” value=”${jdbc.url}”/>
<property name=”user” value=”${jdbc.user}”/>
<property name=”password” value=”${jdbc.password}”/>
<property name=”minPoolSize” value=”${jdbc.minPoolSize}”/>
<property name=”maxPoolSize” value=”${jdbc.maxPoolSize}”/>
</bean>

and this will be your properties file

jdbc.driverClass=oracle.jdbc.driver.OracleDriver
jdbc.url=jdbc:oracle:thin:@abc.com:1521:ORAC
jdbc.user=hello
jdbc.password=hello
jdbc.minPoolSize=1
jdbc.maxPoolSize=10

At run time, the properties file value will be injected  into the applicationContext.xml

Ctrl + Space : Content Assist

syso + Ctrl + space = writes out System.out.Println for you (I love this one)

Ctrl + Shift + T : Open resource box to look for a Java file

Ctrl + Shift + R: Open resource box to look for a non Java file

Ctrl + F8 : Switch between perspective

Ctrl + F11 : Run the last launched

F11 : Run the last launched in debug mode

Ctrl + Page Up / Ctrl + Page Down : Move between open classes

Alt +Shift +J : Add block comments to a clas sor method

Ctrl + Shift + / : Comment the selected code

Ctrl + Shift + \ : Un comment the selected code

Ctrl + / : Add or remove line comments

F3 : open declaration

Ctrl + Shift + L : See all the shortcuts in eclipse , if you do not remember anyone of above