A hyHow does multithreading take place on a computer with a ... - Ning

burgerraraΛογισμικό & κατασκευή λογ/κού

18 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

88 εμφανίσεις

A hy
How does multithreading take place on a computer with a single CPU?(3
marks)

Ans:

I
t is the responsibility of scheduler to organise multiple tasks by allocating
execution time to each task, in such a way that it seems to be executed in a
sequential fas
hion to rest of the world.

What are the two ways to read initialization parameters of a servlet? 5 marks

The ServletConfig object can be used to read init
ialization parameter.

public void init(ServletConfig config) throws ServletException {

string name

=config.getInitParameter(“paramName”);

}

Another way to read initialization parameters out side the init () method is

Call getServletConfig() to obtain the ServletConfig object

Use getInitParameter() of ServletConfig to read initialization parameter
s

public void anyMethod

// defined inside servlet{

ServletConfig config = getServletConfig();

String name = config.getInitParameter(“param_name");

}


What is meant by Twin Tag Libraries?(5 marks)

JSTL comes in two flavors to support various skill set p
ersonal

Expression Language (EL) version :

-

Dynamic attribute values of JSTL tags are specified using JSTL expression
language (i.e. ${expression})

The EL based JSTL tag libraries Sql,Core,Internationalization/ Format ,XML having
prefixes of c,sql,fmt
,x


Request Time (RT) version:

-

Dynamic attribute values of JSTL tags are specified using JSP expression

(i.e. <%= expression %>)

The RT based JSTL tag libraries Sql,Core,Internationalization/ Format ,XML having
prefixes of c_rt,sql_rt,fmt_rt,x_rt


What

impact a JavaBeans object can produce when it is stored in Page scope? (3
marks)

Beans created with page scope are always accessed (their values) by
jsp:getProperty,

jsp:setProperty, scriptlets or expressions
.when
MyBean object ,
are not available.
BEAN specify

scop
e

“pag
e” results in using the object on the
same page where they are created.

The scope attribute is optional and default to page.

A page scoped variable is set to value of request parameter by using

paramimplicit object. If paramete
r is defined in JSP page as:


<input type=”text” value = “
parameter
” />



Can a vector contain heterogenous objects? If yes then explain why?(3 marks)

Ans:

Yes a Vector can contain heterogenous objects. Because a Vector stores
everything in terms of Ob
ject.


How does JSF provide Navigation?(3 marks)

Page navigation determines the control flow of a Web application. JSF provides a
default navigational handler and this behavior can be configured in configuration.
However, you can do it visually in most too
ls like Sun Studio Creator




How can we read cookies from the client? (3 marks)

To read the cookies that
come back from the client, foll
owing steps are generally
followed.

Reading Cookies from the Client

To read incoming cookies, get them from the r
equest objec
t
of the
HttpServeltRequest by calling following method

Cookie cookie s[] = request.getCookies();

This call returns an array of Cookies object corresponding to the name & values
that came in the HT
T
P request header.

Looping down Cookies
:

Once you have an array of

cookies,

you can iterate over it. Two important
methods of Cookie class are

getName
() and getValue().
These are used to
retrieve cookie name and value respectively.





Write the code of java beans class named as "MyBean" and havin
g an attribute
named "name" of String data type.


5 marks

package My Bean;

port java.io.*;

Public class MyBeanClass implements Serializable{


private String name;


// no argument constructor


public MyBeanClass() {


name = "";


}

//setter

public void setName(String n){

name = n;

}

// getters


public String getName( ){


return name;

}

} // end class MyBeanClass

What are the high
-
level thread states?2 mark

The high
-
level thread states are runable,running
,waiting,sleeping
,blocked,blocked on i/o



Name any two typical solutions of session tracking?

The typical solutions come across to accomplish session tracking. These are:

1 Cookies

2 URL Rewriting


Write the syntax of Update SQL query.

Used to execute for INSERT,
UPDATE

or DELETE SQL statements.

For example,


int num = stmt.executeUpdate(“DELETE from Person WHERE id = 2” );


What type of problem persists with Struts Framework?

Struts Framework creates following problems

Adds complexity and doesn’t provide UI t
ags

Very Java programmer centric


What is the meaning of error page if after using url
http://localhost:8080/myapp/index.html in internet explorer an error appear
showing error status 404 at server side?

Ans:

The
404

or
Not Found

error message is a HTT
P standard response code in TOMCAT indicating
that the client was able to communicate with the server, but the server could not find what was
requested.



How does multithreading take place on a computer with a single CPU?(3 marks)

Ans:

t is the responsib
ility of scheduler to organise multiple tasks by allocating
execution time to each task, in such a way that it seems to be executed in a
sequential fashion to rest of the world.

What are the two ways to read initialization parameters of a servlet? 5 marks

The ServletConfig object can be used to read initialization parameter.

public void init(ServletConfig config) throws ServletException {

string name =config.getInitParameter(“paramName”);

}

Another way to read initialization parameters out side the in
it () method is

Call getServletConfig() to obtain the ServletConfig object

Use getInitParameter() of ServletConfig to read initialization parameters

public void anyMethod

// defined inside servlet{

ServletConfig config = getServletConfig();

String n
ame = config.getInitParameter(“param_name");

}


What is meant by Twin Tag Libraries?(5 marks)

JSTL comes in two flavors to support various skill set personal

Expression Language (EL) version :

-

Dynamic attribute values of JSTL tags are specified using JS
TL expression
language (i.e. ${expression})

The EL based JSTL tag libraries Sql,Core,Internationalization/ Format ,XML having
prefixes of c,sql,fmt,x


Request Time (RT) version:

-

Dynamic attribute values of JSTL tags are specified using JSP expression


(i.e. <%= expression %>)

The RT based JSTL tag libraries Sql,Core,Internationalization/ Format ,XML having
prefixes of c_rt,sql_rt,fmt_rt,x_rt


What impact a JavaBeans object can produce when it is stored in Page scope? (3
marks)

Beans created with pag
e scope are always accessed (their values) by
jsp:getProperty,

jsp:setProperty, scriptlets or expressions.when MyBean object ,
are not available. BEAN specify scope “page” results in using the object on the
same page where they are created.

The sco
pe attribute is optional and default to page.

A page scoped variable is set to value of request parameter by using

paramimplicit object. If parameter is defined in JSP page as:


<input type=”text” value = “parameter” />



Can a vector contain hetero
genous objects? If yes then explain why?(3 marks)

Ans:

Yes a Vector can contain heterogenous objects. Because a Vector stores
everything in terms of Object.


How does JSF provide Navigation?(3 marks)

Page navigation determines the control flow of a Web app
lication. JSF provides a
default navigational handler and this behavior can be configured in configuration.
However, you can do it visually in most tools like Sun Studio Creator




How can we read cookies from the client? (3 marks)

To read the cookies th
at come back from the client, following steps are generally
followed.

Reading Cookies from the Client

To read incoming cookies, get them from the request object of the
HttpServeltRequest by calling following method

Cookie cookie s[] = request.getCook
ies();

This call returns an array of Cookies object corresponding to the name & values
that came in the HTTP request header.

Looping down Cookies:

Once you have an array of cookies,

you can iterate over it. Two important
methods of Cookie class are get
Name() and getValue().These are used to
retrieve cookie name and value respectively.





Write the code of java beans class named as "MyBean" and having an attribute
named "name" of String data type.


5 marks

package My Bean;

port java.io.*;

Public cl
ass MyBeanClass implements Serializable{


private String name;


// no argument constructor


public MyBeanClass() {


name = "";


}

//setter

public void setName(String n){

name = n;

}

// getters


public String getName( ){


retur
n name;

}

} // end class MyBeanClass