Skip to main content

Privado.com - A Private Search Engine

https://www.privado.com/ Your searches should be private. We make sure they really are.  Private Search in Action  We don’t track you  We don’t store your searches in any identifiable way  We don’t store your IP address in our services Your privacy is important.  There are no traces of your activities and personal identity in our servers.  You can learn more about privacy in our blog  We don't like cookies!   https://www.privado.com/

Java J2EE Interview Questions and Answers - Part 5

  1. Which containers use a Border layout as their default layout?- Window, Frame and Dialog classes use a BorderLayout as their layout.
  2. Which containers use a Flow layout as their default layout?- Panel and Applet classes use the FlowLayout as their default layout.
  3. What are wrapper classes?- Wrapper classes are classes that allow primitive types to be accessed as objects.
  1. What are Vector, Hashtable, LinkedList and Enumeration?- Vector : The Vector class provides the capability to implement a growable array of objects. Hashtable : The Hashtable class implements a Hashtable data structure. A Hashtable indexes and stores objects in a dictionary using hash codes as the object’s keys. Hash codes are integer values that identify objects. LinkedList: Removing or inserting elements in the middle of an array can be done using LinkedList. A LinkedList stores each object in a separate link whereas an array stores object references in consecutive locations. Enumeration: An object that implements the Enumeration interface generates a series of elements, one at a time. It has two methods, namely hasMoreElements() and nextElement(). HasMoreElemnts() tests if this enumeration has more elements and nextElement method returns successive elements of the series.
  2. What is the difference between set and list?- Set stores elements in an unordered way but does not contain duplicate elements, whereas list stores elements in an ordered way but may contain duplicate elements.
  3. What is a stream and what are the types of Streams and classes of the Streams?- A Stream is an abstraction that either produces or consumes information. There are two types of Streams and they are: Byte Streams: Provide a convenient means for handling input and output of bytes. Character Streams: Provide a convenient means for handling input & output of characters. Byte Streams classes: Are defined by using two abstract classes, namely InputStream and OutputStream. Character Streams classes: Are defined by using two abstract classes, namely Reader and Writer.
  1. What is the difference between Reader/Writer and InputStream/Output Stream?- The Reader/Writer class is character-oriented and the InputStream/OutputStream class is byte-oriented.
  2. What is an I/O filter?- An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.
  3. What is serialization and deserialization?- Serialization is the process of writing the state of an object to a byte stream. Deserialization is the process of restoring these objects.
  1. What is JDBC?- JDBC is a set of Java API for executing SQL statements. This API consists of a set of classes and interfaces to enable programs to write pure Java Database applications.
  2. What are drivers available?- a) JDBC-ODBC Bridge driver b) Native API Partly-Java driver c) JDBC-Net Pure Java driver d) Native-Protocol Pure Java driver
  3. What is the difference between JDBC and ODBC?- a) OBDC is for Microsoft and JDBC is for Java applications. b) ODBC can’t be directly used with Java because it uses a C interface. c) ODBC makes use of pointers which have been removed totally from Java. d) ODBC mixes simple and advanced features together and has complex options for simple queries. But JDBC is designed to keep things simple while allowing advanced capabilities when required. e) ODBC requires manual installation of the ODBC driver manager and driver on all client machines. JDBC drivers are written in Java and JDBC code is automatically installable, secure, and portable on all platforms. f) JDBC API is a natural Java interface and is built on ODBC. JDBC retains some of the basic features of ODBC.
  1. What are the types of JDBC Driver Models and explain them?- There are two types of JDBC Driver Models and they are: a) Two tier model and b) Three tier model Two tier model: In this model, Java applications interact directly with the database. A JDBC driver is required to communicate with the particular database management system that is being accessed. SQL statements are sent to the database and the results are given to user. This model is referred to as client/server configuration where user is the client and the machine that has the database is called as the server. Three tier model: A middle tier is introduced in this model. The functions of this model are: a) Collection of SQL statements from the client and handing it over to the database, b) Receiving results from database to the client and c) Maintaining control over accessing and updating of the above.
  2. What are the steps involved for making a connection with a database or how do you connect to a database? a) Loading the driver : To load the driver, Class. forName() method is used. Class. forName(”sun. jdbc. odbc. JdbcOdbcDriver”); When the driver is loaded, it registers itself with the java. sql. DriverManager class as an available database driver. b) Making a connection with database: To open a connection to a given database, DriverManager. getConnection() method is used. Connection con = DriverManager. getConnection (”jdbc:odbc:somedb”, “user”, “password”); c) Executing SQL statements : To execute a SQL query, java. sql. statements class is used. createStatement() method of Connection to obtain a new Statement object. Statement stmt = con. createStatement(); A query that returns data can be executed using the executeQuery() method of Statement. This method executes the statement and returns a java. sql. ResultSet that encapsulates the retrieved data: ResultSet rs = stmt. executeQuery(”SELECT * FROM some table”); d) Process the results : ResultSet returns one row at a time. Next() method of ResultSet object can be called to move to the next row. The getString() and getObject() methods are used for retrieving column values: while(rs. next()) { String event = rs. getString(”event”); Object count = (Integer) rs. getObject(”count”);
  3. What type of driver did you use in project?- JDBC- ODBC Bridge driver (is a driver that uses native(C language) libraries and makes calls to an existing ODBC driver to access a database engine).

Comments

Post a Comment

Popular Posts

DOT NET Interview Questions with Answers

When not to use Design Patterns? Do not use design patterns in any of the following situations. • When the software being designed would not change with time. • When the requirements of the source code of the application are unique. If any of the above applies in the current software design, there is no need to apply design patterns in the current design and increase unnecessary complexity in the design. When to use Design Patterns? Design Patterns are particularly useful in one of the following scenarios. • When the software application would change in due course of time. • When the application contains source code that involves object creation and event notification. Benefits of Design Patterns: The following are some of the major advantages of using Design Patterns in software development. • Flexibility • Adaptability to change • Reusability What are Design Patterns? A Design Pattern essentially consists of a problem in a software design and a solutio

Freewares / Free Softwares 19 Nov 09

Quick Config Quick Config is a convenient tool to help change quickly various settings of your computer. This is a useful utility especially for those who travel with their laptops and wish to change network connection settings, set default printer and etc, with just a click. All one needs to do is to create one or more configuration profiles, set the required settings for each profile, and when a change is needed activate the profile by double clicking on it. Features: The current version of Quick Config can change - TCP/IP settings (IP address, mask, gateway, DNS server, MAC), state of network connection; computer name, domain or workgroup membership; map, unmap network drives; share, unshare local resources; Hosts file; Routing table, Sound volume and theme; Set default printer; Start, stop, restart system services; IE, FireFox and Opera network connection settings, Desktop- Display screen dimensions, color depth; and change default applications such as E-Mail client and o

CG CoreEI Offcampus for Freshers: Dec 5

Company        CG CoreEl Programmable Solutions About Company CG CoreEl Programmables Pvt. Ltd. in Bangalore is a VLSI design house, which provides embedded system design services with emphasis on quality deliverables. Our core business offerings are design services in the areas of FPGA, ASIC, PCB and embedded system level requirements. A visit to our web site www.cg-coreel.com would give you a detailed view of our offerings as an Employer. We believe in providing state of the art facilities and technical tools to our technical team to evaluate and deliver. We have to our credit an independent Engineering facility to house over 300 engineers. Batch      2008/2009 Passouts Outside Kerala Students     Registration of outside Kerala students less than 16000 is invalidnow.Outside Kerala Students with Reg No under 16,000 will have to register afresh. Such Candidates who have taken SHREDS Cards should get the old register numbers corrected by SHREDS Secretary. Date     Saturday 5th Dece

Probationary/ Specialist Officers in Indian Bank

Probationary/ Specialist Officers Location :  Across India Eligibility: BE/ B.Tech (Che/ Electrical/ Mech/ Prdn/ Textile/ ETE/ ECE/ CS/ IT)/ MCA/ MBA www.freshersworld.com Details:     Indian Bank (A Govt of India Undertaking) Recruitment of Probationary Officers/ Specialist Officers (Industrial Development Officers/ Computer Officers) Indian Bank, a leading Public Sector Bank, with headquarters in Chennai having geographical presence all over India and abroad invites online applications from Indian Citizens for the following posts. Post Code Post Scale Total Vacancy Age as on 01.07.09 Min Max 1 Probationary Officers I 118 21 30 Specialist Officers         Industrial Development Officers in the following Engineering disciplines         2 Chemical I 02 21 30 3 Electrical I 02 21 30 4 Electronics I 02 21 30 5 Leather Technology I 02 21 30 6 Mechanical I 02 21 30 7 Production/ Metallurgy I 02

DesignEvo - A free and easy online logo designer

DesignEvo is  easy-to-use online logo design tool with millions of icons, 100+ stylish  fonts, 3,000+ practical logo templates and handy editing tools. It can help  people easily create appealing and effective logos for their brands,  websites, blogs, social media channels, etc.  It is really awesome and intuitive interface. Easy to design and customize. A person can easily design by selecting a pre-defined logo design and modify it on the fly. Hardly you need 1 minute to design your new logo with minor modifications. Its really awesome site. I suggest you to try it out.   You can discover more about DesignEvo here: https://www.designevo.com Learn more about Designevo  @ YouTube designevo, free logo design, logo maker, create a logo, easy logo maker, design logo free, free logo, logo designs, logo images

Contact Form

Name

Email *

Message *