Over the years, the Enterprise Java Technologies Tech Tips have covered a wide variety of enterprise Java technology topics. Here's a short quiz that tests your knowledge of some topics covered in past Tech Tips. You can find the answers at the end of the quiz.

1.                  Which of the following inheritance strategies is not supported by the Java Persistence API?

a.                               Single Table Per Class Hierarchy

b.                              Joined Subclass

c.                               Single Table Per Class

d.                              Multiple Hierarchy

2.                  What is the primary purpose of the javax.xml.ws.Provider API?

a.                               Binds XML to Java objects.

b.                              Allows web services to work directly with messages.

c.                               Simplifies WSDL creation.

d.                              Specifies the URL of a web service provider.

e.                               None of the above

3.                  Which of the following statements about the ELResolver class is true?

a.                               In Java EE 5, the classes VariableResolver and PropertyResolver have been merged into the ELResolver class.

b.                              The way an expression is resolved can be customized by adding custom ELResolver subclasses to the ELResolver chain.

c.                               To make an ELResolver class visible to the Java EE runtime, it must be declared in an application configuration resource file.

d.                              All of the above.

4.                  What does the <service-name-pattern> element in the following set of XML statements do: 
            <handler-chains xmlns="http://java.sun.com/xml/ns/javaee">
              <handler-chain>\
               <service-name-pattern   xmlns:ns1="http://example.com/handlers">
                ns1:HelloService      
                  </service-name-pattern>
                        <handler/>
                        <handler/>
                    </handler-chain>
              </handler-chains>
    

a.                               Applies the handlers specified in the <handler-chain> element to the service with the Java EE qname {http://example.com/handlers}HelloService .

b.                              Adds a service named HelloService to the handlers specified in the <handler-chain> element.

c.                               Applies the handlers specified in the <handler-chain> element to all ports whose names begin with HelloService .

d.                              None of the above.

5.                  What role does an XMLHttpRequest object play in an AJAX-enabled application?

a.                               It's used as a proxy to transmit requests to a server in a different domain.

b.                              It's used to identify a filter for exchange of XML-based AJAX requests between the client and server.

c.                               It's used to transmit AJAX requests asynchronously over HTTP to a server-side component.

d.                              There is no such thing as an XMLHttpRequest object.

Answers

1.                  Which of the following inheritance strategies is not supported by the Java Persistence API?

d.                              Multiple Hierarchy. The Java Persistence API allows for three different inheritance strategies that dictate how subclasses are mapped to database tables. The three strategies are single table per class hierarchy, joined subclass, and single table per class. 

2.                  What is the primary purpose of the javax.xml.ws.Provider API?

b.                              Allows web services to work directly with messages. The JAX-WS 2.0 specification provides two new APIs which make it possible for web services to work with messages or message payloads. The APIs are javax.xml.ws.Provider and java.xml.ws.Dispatch . Provider is a server-side API, while Dispatch is a client-side API. 
 

3.                  Which of the following statements about the ELResolver class is true?

d.                              All of the above. For more about the ELResolver class, especially how to create a customized ELResolver .

4. What does the <service-name-pattern> element in the following set of XML statements do: 
            <handler-chains xmlns="http://java.sun.com/xml/ns/javaee">        
            <handler-chain>       
                 <service-name-pattern 
                   xmlns:ns1="http://example.com/handlers">     
                      ns1:HelloService
                       </service-name-pattern>  
                <handler/>  
                <handler/>
                 </handler-chain>
           </handler-chains>
    e.       Applies the handlers in the specified in the <handler-chain>element to the service with the Java EE qname {http://example.com/handlers}HelloService. The <service-name-pattern>element applies handlers to specific services. Handlers are interceptors that can be easily plugged into the JAX-WS 2.0 runtime environment to do additional processing of inbound and outbound messages. A handler chain is an ordered list of handlers that is used for configuring handlers. .

5.What role does an XMLHttpRequest object play in an AJAX-enabled application?

  c.      It's used to transmit AJAX requests asynchronously over HTTP to a server-side component. An XMLHttpRequest object plays a central role in the AJAX methodology as the means of interaction between the client and server-side component that processes AJAX requests. 

<?xml version="1.0"?>

   < xsl:stylesheet version="1.0"

            xmlns:xsl="http://www.w3.org/1999/ XSL/Transform">

< /xsl:stylesheet >

4). Using XSLT, how would you extract a specfic attribute from an element in an XML document?
Ans: Extract attributes from XML data
   <xsl:template match="element-name">
     Attribute Value:
        <xsl:value-of select="@attribute" />
         <xsl:apply-templates/>
    </xsl:template>

5). Templates--Controls which output is created from which input

--" xsl:template element form

--" match attribute contains an Xpath expression (Xpath expression identifies input node set it matches)

--" For each node in the node set, the

template contents (things between xsl:template tags) are instantiated and inserted into the output tree.

6). Attributes

In the DTD, XML element attributes are declared with an ATTLIST declaration. An attribute declaration has the following syntax:

<!ATTLIST element-name attribute-name attribute-type default-value>

The attribute-type can have the following values:

CDATA

The value is character data

(eval|eval|..)

The value must be an enumerated value

ID

The value is an unique id 

IDREF

The value is the id of another element

IDREFS

The value is a list of other ids

NMTOKEN

The value is a valid XML name

NMTOKENS

The value is a list of valid XML names

ENTITY

The value is an entity 

ENTITIES

The value is a list of entities

NOTATION

The value is a name of a notation

xml:

The value is predefined

The attribute-default-value can have the following values:

#DEFAULT value

The attribute has a default value

#REQUIRED

The attribute value must be included in the element

#IMPLIED

The attribute does not have to be included

#FIXED value

The attribute value is fixed

Attribute declaration example

DTD example:
<!ELEMENT square EMPTY>
  <!ATTLIST square width CDATA "0">

XML example:
<square width="100"></square>

Default attribute value

Syntax:
<!ATTLIST element-name attribute-name CDATA "default-value">

DTD example:
<!ATTLIST payment type CDATA "check">

XML example:
<payment type="check">

Implied attribute

Syntax:
<!ATTLIST element-name attribute-name attribute-type #IMPLIED>

DTD example:
<!ATTLIST contact fax CDATA #IMPLIED>

XML example:
<contact fax="555-667788">

Required attribute

Syntax:
<!ATTLIST element-name attribute_name attribute-type #REQUIRED>

DTD example:
<!ATTLIST person number CDATA #REQUIRED>

XML example:
<person number="5677">

Fixed attribute value

Syntax:
<!ATTLIST element-name attribute-name attribute-type #FIXED "value">

DTD example:
<!ATTLIST sender company CDATA #FIXED "Microsoft">


XML example:
<sender company="Microsoft">

Enumerated attribute values

Syntax:
<!ATTLIST element-name attribute-name (eval|eval|..) default-value>

DTD example:
<!ATTLIST payment type (check|cash) "cash">

XML example:
<payment type="check">
or
<payment type="cash">