• A procedure is a named PL/SQL block which performs one or more specific task.This is similar to a procedure in other programming languages.
• A procedure has a header and a body.
• The header consists of the name of the procedure and the parameters or variables passed to the procedure.
• The body consists declaration section, execution section and exception section similar to a general PL/SQL Block. A procedure is similar to an anonymous PL/SQL Block but it is named for repeated usage.

• A function is a named PL/SQL Block which is similar to a procedure.
• The major difference between a procedure and a function is, a function must always return a value, but a procedure may or may not return a value.

• Yes, we can define constructor in Servlet class.
• Constructor may be a Default Constructor or Parameterised Constructor. If we didn’t write any constructor then the default constructor will be executed. Because, to read init parameters of a servlet we need servlet config object in the life cycle of the servlet.
• Servlet config object is created after the execution of the constructor.

• Indexing is the One of the ways that will optimize the database searching and accessing is having indexes on the columns that access the data in a database table.
• An index object is created in database with the column/columns value that are mentioned while creating the index.
• The value in the index holds the row id of the physical data location in the database which helps for fast data retrieval of the corresponding rows.

• Clustered indexes define the physical sorting of a database table’s rows in the storage media. For this reason, each database table may have only one clustered index.
• Non-clustered indexes are created outside of the database table and contain a sorted list of references to the table itself.

• Indexes their use in queries usually results in much better performance.
• Make it possible to quickly retrieve (fetch) data.
• They can be used for sorting. A post-fetch-sort operation can be eliminated.
• Unique indexes guarantee uniquely identifiable records in the database.

• They decrease performance on inserts, updates, and deletes.
• It will take up space (this increases with the number of fields used and the length of the fields).
• Some databases will monocase values in fields that are indexed.

• DBMS is represented by the DataBase Management System. A database management system (DBMS) is a software that allows creation, definition and manipulation of database, allowing users to store, process and analyze data easily.
• DBMS provide us with an interface or a tool, to perform various operations like creating database, storing data in it, updating data, creating tables in the database and a lot more.
• DBMS also provides protection and security to the databases.
• It also maintains data consistency in case of multiple users.
• Here are some examples of popular DBMS used these days:
  • MySQL
  • Oracle
  • SQL Server
  • IBM DB2
  • PostgreSQL
  • Amazon Simple DB (cloud based) etc.

• Hierarchical Databse Model.
• Network Databse Model.
• Relational Databse Model.
• Object-Oriented Databse Model.

• In a Hierarchical database model, the data is organized in a tree-like structure.
• Data is Stored Hierarchically (top down or bottom up) format.
• Data is represented using a parent-child relationship that are one to one or one to many.
• In Hierarchical DBMS parent may have many children, but children have only one parent.

• The network database model allows each child to have multiple parents.
• If you need to address the model help us to more complex relationships like as the orders/parts many-to-many relationship.
• In this model, the entities are organized in a graph which can be accessed through several paths.

• Relational DBMS is the most widely used DBMS model because it is one of the easiest.
• This model is based on normalizing data in the rows and columns of the tables.
• Relational model stored in fixed structures and manipulated using SQL.

• In Object-oriented Model data stored in the form of objects.
• The structure which is called classes which display data within it. It defines a database as a collection of objects which stores both data members values and operations.

• Improved data sharing.
• Improved data security.
• Better data integration.
• Minimized data inconsistency.
• Improved data access.
• Improved decision making.
• Increased end-user productivity.

• Increased costs.
• Management complexity.
• Maintaining currency.
• Frequent upgrade/replacement cycles.

• Software Development Life Cycle (SDLC) is a set of phases that provide a common understanding of the software building process.
• How the software is realized and developed from the business understanding and requirements elicitation phase to convert these business ideas and requirements into functions and features until its usage and operation to achieve the business needs.
• Generally a software engineer should have enough knowledge on how to select the SDLC model based on the project context and the business requirements.
• Therefore, it may be required to choose the right SDLC model according to the specific concerns and requirements of the project to ensure its success.
• You can think of SDLC models as tools that you can use to better deliver your software project. Therefore, knowing and understanding each model and when to use it, the advantages and disadvantages of each one are important to know which one is suitable for the project context.

• There are some various software development life cycle models defined and designed which are followed during the software development process. These models are also referred as Software Development Process Models”.
• Each process model based on a Series of rules unique to its type to ensure success in the process of software development.

• Following are the most important and popular SDLC models followed in the industry & miuns

• • Waterfall Model
  • Iterative Model
  • Spiral Model
  • V-Model
  • Big Bang Model

• The waterfall is a widely accepted SDLC model. In this approach, the whole process of the software development is divided into various phases. In this SDLC model, the outcome of one phase acts as the input for the next phase.
• This SDLC model is documentation-intensive, with earlier phases documenting what need be performed in the subsequent phases.

• The incremental model is not a separate model. It is essentially a series of waterfall cycles.
• The requirements are divided into groups at the start of the project. For each group, the SDLC model is followed to develop software.
• The SDLC process is repeated, with each release adding more functionality until all requirements are met. In this method, every cycle act as the maintenance phase for the previous software release.
• Modification to the incremental model allows development cycles to overlap. After that subsequent cycle may begin before the previous cycle is complete.

• In this type of SDLC model testing and the development, the phase is planned in parallel.
• So, there are verification phases on the side and the validation phase on the other side. V-Model joins by Coding phase.

• Agile methodology is a practice which promotes continue interaction of development and testing during the SDLC process of any project.
• In the Agile method, the entire project is divided into small incremental builds. All of these builds are provided in iterations, and each iteration lasts from one to three weeks.

• Phase 1: Requirement collection and analysis
• Phase 2: Feasibility study
• Phase 3: Design
• Phase 4: Coding
• Phase 5: Testing
• Phase 6: Installation/Deployment
• Phase 7: Maintenance

• The requirement is the first stage in the SDLC process. It is conducted by the senior team members with inputs from all the stakeholders and domain experts in the industry.
• Planning for the quality assurance requirements and recognization of the risks involved is also done at this stage.

• Once the requirement analysis phase is completed the next step is to define and document software needs.
• This process conducted with the help of ‘Software Requirement Specification’ document also known as ‘SRS’ document.

• Economic: Can we complete the project within the budget or not ?
• Legal: Can we handle this project as cyber law and other regulatory framework/compliances.
• Operation feasibility: Can we create operations which is expected by the client ?
• Technical: Need to check whether the current computer system can support the software
• Schedule: Decide that the project can be completed within the given schedule or not.

• In this third phase, the system and software design documents are prepared as per the requirement specification document. This helps define overall system architecture.
• This design phase serves as input for the next phase of the model.There are two kinds of design documents developed in this phase,

• Brief description and name of each module
• An outline about the functionality of every module
• Interface relationship and dependencies between modules
• Database tables identified along with their key elements
• Complete architecture diagrams along with technology details

• Functional logic of the modules
• Database tables, which include type and size
• Complete detail of the interface
• Addresses all types of dependency issues
• Listing of error messages
• Complete input and outputs for every module

• Once the system design phase is over, the next phase is coding. In this phase, developers start build the entire system by writing code using the chosen programming language.
• In the coding phase, tasks are divided into units or modules and assigned to the various developers. It is the longest phase of the Software Development Life Cycle process.
• In this phase, Developer needs to follow certain predefined coding guidelines. They also need to use programming tools like compiler, interpreters, debugger to generate and implement the code.

• Once the software is complete, and it is deployed in the testing environment. The testing team starts testing the functionality of the entire system.
• This is done to verify that the entire application works according to the customer requirement.

• Once the software testing phase is over and no bugs or errors left in the system then the final deployment process starts.
• Based on the feedback given by the project manager, the final software is released and checked for deployment issues if any.

• Bug fixing – bugs are reported because of some scenarios which are not tested at all
• Upgrade – Upgrading the application to the newer versions of the Software
• Enhancement – Adding some new features into the existing software

• Software Testing Life Cycle (STLC) is the testing process which is executed in systematic and planned manner.
• In STLC process, different activities are carried out to improve the quality of the product.

• Requirement Analysis
• Test Planning
• Test Case Development
• Environment Setup
• Test Execution
• Test Cycle Closure

• Requirement Analysis is the very first step in Software Testing Life Cycle (STLC). In this step Quality Assurance (QA) team understands the requirement in terms of what we will testing & figure out the testable requirements.
• If any conflict, missing or not understood any requirement, then QA team follow up with the various stakeholders like Business Analyst, System Architecture, Client, Technical Manager/Lead etc., to better understand the detail knowledge of requirement.

• Test Planning is most important phase of Software testing life cycle where all testing strategy is defined.
• This phase also called as Test Strategy phase. In this phase typically Test Manager (or Test Lead based on company to company) involved to determine the effort and cost estimates for entire project.

• The test case development activity is started once the test planning activity is finished.
• This is the phase of STLC where testing team write down the detailed test cases. Along with test cases testing team also prepare the test data if any required for testing.
• Once the test cases are ready then these test cases are reviewed by peer members or QA lead.

• Setting up the test environment is vital part of the STLC. Basically test environment decides on which conditions software is tested.
• This is independent activity and can be started parallel with Test Case Development. In process of setting up testing environment test team is not involved in it.

• Once the preparation of Test Case Development and Test Environment setup is completed then test execution phase can be kicked off.
• In this phase testing team start executing test cases based on prepared test planning & prepared test cases in the prior step.

• Call out the testing team member meeting & evaluate cycle completion criteria based on Test coverage, Quality, Cost, Time, Critical Business Objectives and Software.
• Discuss what all went good, which area needs to be improve & taking the lessons from current STLC as input to upcoming test cycles, which will help to improve bottleneck in the STLC process.

• UDP vs TCP – TCP/IP means Transmission Control Protocol and Internet Protocol. It is the network model used in the current Internet architecture as well.
• Protocols are set of rules which govern every possible communication over a network.
• These protocols describe the movement of data between the source and destination or the internet. They also offer simple naming and addressing schemes.

• Support for a flexible architecture. Adding more machines to a network was easy.
• The network was robust, and connections remained intact until the source and destination machines were functioning.

• Lowest layer of the all.
• Protocol is used to connect to the host, so that the packets can be sent over it. Varies from host to host and network to network.

• Selection of a packet switching network which is based on a connectionless internetwork layer is called a internet layer. This layer which holds the whole architecture together.
• It helps the packet to travel independently to the destination.
• Order in which packets are received is different from the way they are sent.
• IP (Internet Protocol) is used in this layer.

• Delivering IP packets.
• Performing routing.
• Avoiding congestion.

• It decides if data transmission should be on parallel path or single path.
• Functions such as multiplexing, segmenting or splitting on the data is done by transport layer.
• The applications can read and write to the transport layer.
• Transport layer adds header information to the data.
• Transport layer breaks the message (data) into small units so that they are handled more efficiently by the network layer.
• Transport layer also arrange the packets to be sent, in sequence.

• The TCP/IP specifications described a lot of applications that were at the top of the protocol stack. Some of them were TELNET, FTP, SMTP, DNS etc.
  • TELNET is a two-way communication protocol which allows connecting to a remote machine and run applications on it.
  • FTP (File Transfer Protocol) is a protocol, that allows File transfer amongst computer users connected over a network. It is reliable, simple and efficient.
  • SMTP (Simple Mail Transport Protocol) is a protocol, which is used to transport electronic mail between a source and destination, directed via a route.
  • DNS (Domain Name Server) resolves an IP address into a textual address for Hosts connected over a network.
• It allows peer entities to carry conversation.
• It defines two end-to-end protocols : TCP and UDP
  • TCP (Transmission Control Protocol) : It is a reliable connection-oriented protocol which handles byte-stream from source to destination without error and flow control.
  • UDP (User-Datagram Protocol) : It is an unreliable connection-less protocol that do not want TCPs, sequencing and flow control. For Example One-shot request-reply kind of service.

• It operated independently.
• It is scalable.
• Client/server architecture.
• Supports a number of routing protocols.
• Can be used to establish a connection between two computers.

• In this layer does not guarantee delivery of packets.
• The model cannot be used in any other application.
• Replacing protocol is not easy.
• It has not clearly separated its services, interfaces and protocols.

• Switching is the most valuable asset of computer networking.
• Everytime in computer network you have access the internet or another computer network outside your immediate location, or your messages are sent through a maze of transmission media and connection devices.
• The mechanism for exchange of information between different computer networks and network segments is called switching in Networking.
• On the other words we can say that any type signal or data element directing or Switching toward a particular hardware address or hardware pieces.
• Hardware devices that can be used for switching or transferring data from one location to another that can use multiple layers of the Open Systems Interconnection (OSI) model.

• There are basically three types of switching methods are available.
  • Circuit Switching
  • Packet Switching
  • Message Switching

• Circuit-switching is the real-time connection-oriented system. In Circuit Switching a dedicated channel (or circuit) is set up for a single connection between the sender and recipient during the communication session.
• In telephone communication system, the normal voice call is the example of Circuit Switching. The telephone service provider maintain a unbroken link for each telephone call.
• Circuit switching is pass through three phases, that are circuit establishment, data transfer and circuit disconnect.

• The basic example of Packet Switching is the Internet. In Packet Switching, data can be fragmented into suitably-sized pieces in variable length or blocks that are called packets that can be routed independently by network devices based on the destination address contained certain “formatted” header within each packet.
• The packet switched networks allow sender and recipient without reserving the circuit. Multiple paths are exist between sender and recipient in a packet switching network.
• They does not require a call setup to transfer packets between sender and recipient.

• There are two type of Packet Switching connectionless or Connection-Oriented.

• It is also known as datagram switching. In this type of network each packet routed individually by network devices based on the destination address contained within each packet.
• Due to each packet is routed individually, the result is that each packet is delivered out-of-order with different paths of transmission, it depend on the networking devices like (switches and routers) at any given time.
• After reaching recipient location, the packets are reassemble to the original form.

• It is also known as virtual circuit switching. In this type of Networking packets are send in sequential order over a defined route.

• Message switching does not set up a dedicated channel (or circuit) between the sender and recipient during the communication session.
• In Message Switching each message is treated as an independent blocks.
• In this type of networking, each message is then transmitted from first network device to second network device through the internetwork i.e. message is transmitted from the sender to intermediate device.

• The intermediate device stores the message for a time being, after inspects it for errors, intermediate device transmitting the message to the next node with its routing information. Because the message switching networks are called store and forward networks in networking.

• Routing refers to establishing the routes that data packets take on their way to a particular destination.
• This term can be applied to data traveling on the Internet, over 3G or 4G networks, or over similar networks used for telecom and other digital communications setups. Routing can also take place within proprietary networks.

• Every network Routing protocol performs three basic functions:
  • Discovery – Identify other routers on the network.
  • Route Management – Keep track of all the possible destinations (for network messages) along with some data describing the pathway of each.
  • Path Determination – Make dynamic decisions for where to send each network message.

• Static Routing is a process in which we have to manually add routes in Routing table.

• No Routing overhead for router CPU which means a cheaper router can be used to do Routing.
• It adds security because only administrator can allow Routing to particular networks only.
• No bandwidth usage between routers.

• For a large network, it is a difficult task for administrator to manually add each route for the network in the Routing table on each router.
• The administrator should have good knowledge of the topology.
• If a new administrator comes, then he has to manually add each route so he should have very good knowledge of the routes of the topology.

• This method where the router is configured to send all packets towards a single router (next hop).
• It is very useful method for small networks or networks with a single entry and exit point.
• Basically this method used in addition to Static and/or Dynamic routing.
• It is generally used with stub routers. A stub router is a router which has only one route to reach all other networks.

• • Dynamic Routing makes automatic adjustment of the routes according to the current state of the route in the Routing table.
  • Dynamic Routing uses protocols to discover network destinations and the routes to reach it.
  • RIP and OSPF are the best examples of dynamic Routing protocol. Automatic adjustment will be made to reach the network destination if one route goes down.

Dynamic Routing

• A dynamic protocol have following features,
  • The routers should have the same dynamic protocol running in order to exchange routes.
  • When a router finds a change in the topology then router advertises it to all other routers.

• Easy to configure.
• More effective at selecting the best route to a destination remote network and also for discovering remote network.

• Consumes more bandwidth for communicating with other neighbours.
• Less secure than static Routing.

• Polymorphism in Java is a concept in different ways we can perform a single action.
• Poly and morphs. The word “poly” means many and “morphs” means forms. Many forms are known as polymorphism.

• There are two types of polymorphism in Java:
  • Compile-Time Polymorphism and
  • Runtime Polymorphism.

• Polymorphism in java we can perform by method overloading and method overriding.

• Java supports Runtime Polymorphism is one of the ways is method overriding
• A call to an overridden method is resolved at run time, rather than compile time it is called as dynamic method dispatch mechanism.
• At run-time, it depends on the type of the object being referred that determines which version of an overridden method will be executed.
• A subclass object refers by a superclass variable. This is also known as upcasting. Java uses this statistic to resolve calls to overridden methods at run time.

• The Binary search tree is a node-based on the binary tree data structure has the following properties,
  • The left-side sub tree of a node contains only nodes with keys lesser than the node’s key.
  • The right-side sub tree of a node contains only nodes with keys greater than the node’s key.
  • The left-side and right-side subtree each must also be a binary search tree.

• Pre-order traversal.
• Post-order traversal.
• In-order traversal.

• This traversal technique it may be traversal order is root-left-right.
  • Visit the node.
  • Call itself to traverse the node’s left subtree.
  • Call itself to traverse the node’s right subtree.

• An object is an abstraction of a real-world entity. It may represent a person, a place, a number and icons or something else that can be modelled. Any data in an object occupy some space in memory and can communicate with each other.

• A class is a collection of objects having common features. It is a user defined datatype which has data members as well functions that manipulate these data’s.

• It can be defined as the separation of unnecessary details or explanation from system requirements so as to reduce the complexities of understanding requirements.

• It is a mechanism that puts the data and function together. It is the result of hiding implementation details of an object from its user.The object hides its data to de accessed by only those functions which are packed in the class of that object.

• It is the relationship between two classes of object such that one of the classes ,the child takes all the relevant features of other class the parent. Inheritance bring about reusability.

• Polymorphism means having many forms that in a single entity can takes more than one form. Polymorphism is implemented through operator overloading and function overloading.

• Dynamic binding is the process of resolving the function to be associated with the respective functions calls during their runtime rather than compile time.

• Every data in an object in oops that is capable of processing request known as message .
• All object can communicate with each other by sending message to each other