Senior Software Engineer

Index hunting helps in improving the speed as well as the query performance of database. The followed measures are achieved to do that:

1) The query optimizer is used to coordinate the study of queries with the workload and the best use of queries suggested based on this.
2) Index, query distribution along with their performance is observed to check the effect.
3) Tuning databases to a small collection of problem queries is also recommended.

The process of collecting, extracting, transforming, and loading data from multiple sources and storing them into one database is known as data warehousing. A data warehouse can be considered as a central repository where data flows from transactional systems and other relational databases and is used for data analytics. A data warehouse comprises a wide variety of organization’s historical data that supports the decision-making process in an organization.

Spring boot provides numbers of starter dependency, here are the most commonly used -
1) Data JPA starter.
2) Test Starter.
3) Security starter.
4) Web starter.
5) Mail starter.
6) Thymeleaf starter.

Spring Boot application scans all the beans and package declarations when the application initializes. You need to add the @ComponentScan annotation for your class file to scan your components added to your project.

The super keyword is used to access hidden fields and overridden methods or attributes of the parent class.
Following are the cases when this keyword can be used:
1) Accessing data members of parent class when the member names of the class and its child subclasses are same.
2) To call the default and parameterized constructor of the parent class inside the child class.
3) Accessing the parent class methods when the child classes have overridden them.

The locator can be termed as an address that identifies a web element uniquely within the webpage. Thus, to identify web elements accurately and precisely we have different types of locators in Selenium:

1) ID
2) ClassName
3) Name
4) TagName
5) LinkText
6) PartialLinkText
7) Xpath
8) CSS Selector
9) DOM

Answer :
driver.close() command closes the currently active window on which the user is working or the window being currently accessed by the web driver.

driver.quit() command, unlike the driver.close() command closes all the windows opened by the program and hence should be used with care.

Both the commands don’t take any parameter and don’t return any value either.

Answer :
1) Garbage Collection in Java is a process by which the programs perform memory management automatically.
2) The Garbage Collector(GC) finds the unused objects and deletes them to reclaim the memory. I
3) In Java, dynamic memory allocation of objects is achieved using the new operator that uses some memory and the memory remains allocated until there are references for the use of the object.
4) When there are no references to an object, it is assumed to be no longer needed, and the memory, occupied by the object can be reclaimed.
5) There is no explicit need to destroy an object as Java handles the de-allocation automatically.
The technique that accomplishes this is known as Garbage Collection. Programs that do not de-allocate memory can eventually crash when there is no memory left in the system to allocate. These programs are said to have memory leaks.

Garbage collection in Java happens automatically during the lifetime of the program, eliminating the need to de-allocate memory and thereby avoiding memory leaks.

In C language, it is the programmer’s responsibility to de-allocate memory allocated dynamically using free() function.This is where Java memory management leads.

An interface refers to a special type of class, which contains methods, but not their definition. Only the declaration of methods is allowed inside an interface. To use an interface, you cannot create objects. Instead, you need to implement that interface and define the methods for their implementation.

Classloader is a subsystem of JVM which is used to load class files. Whenever we run the java program, it is loaded
first by the classloader. There are three built-in classloaders in Java.

1) Bootstrap ClassLoader: This is the first classloader which is the superclass of Extension classloader. It loads the
rt.jar file which contains all class files of Java Standard Edition like java.lang package classes, java.net package
classes, java.util package classes, java.io package classes, java.sql package classes, etc.

2) Extension ClassLoader: This is the child classloader of Bootstrap and parent classloader of System classloader. It
loads the jar files located inside $JAVA_HOME/jre/lib/ext directory.

3) System/Application ClassLoader: This is the child classloader of Extension classloader. It loads the class files from
the classpath. By default, the classpath is set to the current directory. You can change the classpath using "-cp" or "-
classpath" switch. It is also known as Application classloader.

Java Virtual Machine is a virtual machine that enables the computer to run the Java program. JVM acts like a run-time engine which calls the main method present in the Java code. JVM is the specification which must be implemented in the computer system. The Java code is compiled by JVM to be a Bytecode which is machine independent and close to the native code.

Tip : For an experienced professional seeking a change, this is a common question. The easiest method to respond
to this question is to state that you are leaving your current work in order to advance your career. Make sure you don't
criticize or speak poorly about the company where you now work.