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In Maven, SNAPSHOTS are used for ACTIVE projects. You can entirely rely on the snapshot RELEASE when you have SOFTWARE development projects are active. Here, Maven attempt to download the snapshots, when the user runs the build, from a repository.

Follow the below-written STEPS to check the PROPER installation of MAVEN:-

• MAKE a version check by running mvn -V from the command line
• You would see resembling output if you have Maven tool.
• You are all set to use Maven

Learn more about Best Maven Interview Questions with us.

It is ONE of the most common Maven INTERVIEW Question and most accessible to ANSWER and remember.

• Parent Pom
• Project Pom
• Settings
• CLI Parameters

Maven BUILD life cycle is the SEQUENCE of the STEPS for the execution of the goals and tasks of any Maven project. The categories under Maven build life cycle are default, clean and site. Here, the default lifecycle handles the deployment of the project and WHEREAS, the clean life cycle considers the CLEANING of the project. The task of handling the creation of the documentation of the project is dealt with by site lifecycle.

There are THREE TYPES of MAVEN REPOSITORY, namely-

• Local repository
• Central repository
• Remote repository

It is the directory of the JAR files which are packaged and that too with some metadata which are POM files. These are the files used for DOWNLOADING DEPENDENCIES of your dependencies TILL the time when all of them are DOWNLOADED. These are put into the local machine.

Maven INSTALL is used for framing a PROJECT configuration-based DEPENDENCY tree such as pom.xml. On an MVN install, framing project is DONE on all the subjects under downloads/compiles and super pom.xml for all the required components in the directory

• To ease handling of the dependencies on the availability of a lot of dependencies
• Updating the dependencies by choosing the CORRECT update version ID
• Facilitating the process of building, integrating and TESTING of the program ALONG with handling it continuously
• Compiling the source code, generating DOCUMENTS from it and packaging the COMPILED code.

POM, PROJECT Object Model is the fundamental work unit in Maven. Basically, it is an XML file CONTAINING details of the configuration and project INFORMATION with the help of Maven for building the project. The best thing is the AVAILABILITY of the default values for the PROJECTS.

• Helps in BETTER debugging
• Enhanced collaboration
• Clean GENERATED FILES from the project such as .class files
• Improved dependency management
• Project structure CONSISTENCY

A maven is a tool used for software project management and comprehension. Most of the times it is used with projects or software developed in Java, and other PROGRAMMING languages such as RUBY and C#.

• documentation, MANAGING builds, SCM (software configuration management)
• reporting, releases, dependencies
• project compilation WITHIN the IDE with the help of several IDES.

Here are some of the DESIGN PATTERNS USED in SPRING:

• MVC
• Front controller
• View Helper
• Singleton
• Prototype
• Factory
• Builder
• Template
• Proxy
• DI/IOC

Like all MVC frameworks that provide a WAY to work with views, SPRING offers the same feature through the VIEW resolvers. The view resolvers enable the developers to render MODELS in the browser without the need to implement a specific view METHOD. In ViewResolver, you can map view names with actual views. Some of the view resolvers in the Spring framework are InternalResourceViewResolver, ResourceBundleViewResolver, and XmlViewResolver.

Spring Security is one of the security modules in the Spring FRAMEWORK. BASED on the Java SE/Java EE framework, it provides authentication and authorization to web and ENTERPRISE applications. This powerful and highly customizable framework is the de-facto standard for securing all spring-based apps.

@Controller annotation is a specialization of @Component class that ALLOWS the implementation class to be detected through classpath scanning. @Controller annotation annotates Classic controllers. @Controller annotation is used in MVC framework in combination with @RequestMapping annotation in request handling.

DAO or Data Access Object is a design pattern where DAO is an object, which provides an abstract INTERFACE to a DATABASE or some other type of persistence mechanisms. This support AIMS at working with data access technologies like Hibernate and JPA EASY and CONSISTENT.

The @Qualifier annotation in SPRING is used in CASES where the developer has created more beans of the same type but only wants to wire one of them with the said PROPERTY. The @Qualifier annotation can be used with @Autowired for removing the confusion of SPECIFYING and identifying the exact bean to be wired.

Configuration annotation is a part of the spring framework. It indicates that class includes @BEAN definition METHODS. This helps the container process the class and GENERATE BEANS for using in the application and generating definitions and service requests at the runtime.

The Autowiring FEATURE enables developers to inject DEPENDENCIES in the object implicitly. Autowiring internally USES the setter or constructor INJECTION. This feature cannot be used for injecting primitive or string values, and it only WORKS with reference.

Setter Injection is a type of dependency injection (DI) in which the framework uses a setter METHOD to inject dependent objects into the client. The CONTAINER first calls the no-argument constructor and later it calls the setters. Such setter-based injections can work even if dependencies are injected using the constructor.

Constructor injection uses a constructor for injecting dependencies on Spring-managed BEANS. The constructor DI is achieved when the container initiates a CLASS constructor with arguments, each argument REPRESENTING dependencies on other classes.

BeanFactory is the container that instantiates, manages and configures beans. Beans usually collaborate with each another and SHARE dependencies, which are shown in the data used by the BeanFactory.

The APPLICATIONCONTEXT is the INTERFACE within a SPRING application for offering configuration information to the application.

Spring provides 2 types of containers:

• Spring BEANFACTORY Container : It provides basic support for DI and is defined by org.springframework.beans.factory.BeanFactory INTERFACE. BeanFactory and related interfaces are AVAILABLE in Spring for backward compatibility with third-party frameworks.
• Spring ApplicationContext Container : It adds enterprise-specific functionalities to INTERESTED event LISTENERS. It is defined by org.springframework.context.ApplicationContext interface.

Aspect-oriented PROGRAMMING or AOP is a programming approach that allows different properties of a program to DETERMINE how they are compiled into a program. You can use AOP with object-oriented programming or OOP.

Spring framework has 7 modules.

• The Core container MODULE
• Application context module
• AOP module (Aspect Oriented PROGRAMMING)
• JDBC abstraction and DAO module
• O/R mapping INTEGRATION module (Object/Relational)
• Web module
• MVC framework module

Dependency Injection or DI is a DESIGN pattern that implements inversion or change of control for resolving dependencies. It is a process through which OBJECTS define their dependencies. Transferring the task of creating objects to someone ELSE and using the dependency is CALLED dependency injection. It can be done in 2 ways: constructor-based DI and setter-based DI.

Following are the benefits of using Spring Framework:

• Enables developers to use POJO to build enterprise-class applications
• Simpler testing processes
• MVC framework provides good ALTERNATIVE to other FRAMEWORKS, LIKE Struts
• Convenient API TRANSLATES technology-specific exceptions
• Lightweight IoC containers
• Consistent TRANSACTION management interface

Spring is ONE of the most POPULAR open source app development frameworks for enterprise-class Java. Spring is lightweight in terms of size. Some of its core features can be used to develop any Java application, and there are in-built EXTENSIONS on top of the Java EE platform for BUILDING web applications. Spring FRAMEWORK is called a one-stop platform for building enterprise-level Java applications.

There are THREE TYPES of RESULTSET in JDBC, namely

• Forward-only
• Scroll-insensitive
• Scroll-sensitive

It is a standardized protocol ASSURING the implementation of a database commit in such a situation where the commit operation has to be broken into 2 parts. Saving the changes in the database is CALLED commit whereas, rollback is undoing the changes. In the first phase of the commit, data is written into the data records by the servers needing commit data to the log. In the next step, it begins after getting the successful MESSAGE from the previous phase, and the particular object, i.e., the coordinator, SENDS a signal to each SERVER with the instructions of the commit.

The LOCKS are the preventive SOFTWARE mechanism which the other users cannot USE the DATA resource.

• Row and KEY locks
• Page Locks
• Table locks
• Database locks

Connection pooling is a maintained CACHE of DATABASE connections which are kept to be USED for the future use of the database requests arise. It HELPS in improving the performance of the commands to be executed in the database.

PACKAGE Javax.sql is USED for JDBC APPLICATION.

There are SEVERAL JDBC EXCEPTIONS such as

• Java.sql.BatchUpdateException
• java.sql.SQLException
• java.sql.DataTruncation
• java.sql.SQLWarning

It is the point to which the TRANSACTION gets ROLLED back without affecting the preceding work. The method which is used for setting a SAVEPOINT object WITHIN the CURRENT transaction is Connection.setSavepoint().

In JDBC, CARRYING out of all the sets of actions in ONE go is known as a TRANSACTION. It is an atomic action in which either all are carried out, or none of them is carried out. Java Transaction API

The method is used for EXECUTING a query. It returns true if the ResultSet object is the query return. It returns ONE ResultSet object.

Int m = st.executeUpdate(SQL);

If (m==1)

System.out.println (“inserted successfully: “+sql);

Else

System.out.println (“insertion failed”);

It is used for rolling BACK the transactions or committing them explicitly. It is LIKE UNDOING the changes. An action can be rolled back to the same SAVEPOINT more than once.

The two statements in JDBC, such as PreparedStatement, and CallableStatement are USED for DEFINING the properties and the METHODS for letting the user send PL/SQL or SQL commands. Also, RECEIVING the data from the database and determining the methods for bridging the data type differences become comfortable with the statement interfaces.

The FOLLOWING are the TYPES of JDBC drivers-

• JDBC-ODBC BRIDGE DRIVER
• Native-API Driver
• All Java+ Middleware translation driver
• Pure Java Driver

• IMPORT JDBC packages and then load in any of the FOLLOWING WAYS- Class.forName(), DriverManager.registerDriver(). Then register JDBC driver
• Open the connection to the database Connection con= DriverManager.getConnection (url, user, password)
• To PERFORM a query, create a statement object Statement st= con.createStatement ();
• Implement the statement object and then RETURN the query resultset. After that process it.
• Close the resultset, statement objects, and the connection Con.close();

This JAVA SE TECHNOLOGY is used for building connecting java application with the database. It gets automatically installed with JDK software and used for the communication of Java application to the database in the platform and database INDEPENDENT MANNER.

• Exception handling- In the new features of JDBC 4.0, there is an addition of the abilities to recover from the exceptions by including support for the chained exceptions. These are used for the retrieval of the chained exceptions.
• Driver and connection management- DriverManager with the appropriate DataSource object GIVES way to the connection retrieval and allows the portability and transparency of the data source INSTANCE. There are no requirements of bringing any changes in the APPLICATION code for building a connection to the different DATABASE instance.
• Data type support- Additions of some new data types and the rise in the support for others is another UNIQUE feature of JDBC 4.0. Also, new features of the interface, SQLML are added.
• Changes in API- Important and most required API changes have been done here in JDBC 4.0- Array, Connection and PooledConnection, DatabaseMetaData, Wrapper, Statement, PreparerdStatement, and CallableStatement, etc.