Java
If one class can be described as a 'specific example' of another, that relationship can be described as what OOP principal?
Inheritance
What are the three main stages in the LifeCycle of Servlet?
init (called once per lifecycle)
service (called once per request)
destroy (called once per lifecycle)
What is Angular?
Angular is framework for building client-side applications in HTML, CSS, and Typescript
What is SOAP?
SOAP or Simple Object Access Protocol is a protocol designed to exchange information in the form of Web Services. It is primarily based on XML documents exchanged over HTTP, but it's possible to transmit messages through other mediums like email and JMS.
What is IoC? What are the advantages?
Inversion of control - this is a principal in software engineering by which the control of objects or portions of a program is transferred to a container or framework.
IoC enables the framework to take control of the flow of a program and make calls to our custom code
Advantages of this architecture :
- decoupling the execution of a task from its implementation
- making it easier to switch between different implementations
- greater modularity of a program
- greater ease in testing a program by isolating components
What is the difference between the = and == operators?
The = operator is assignment, the == operator tests equality
What are some of the HTTP Status Codes and what do they mean?
(at least 3 specific codes)
200 OK. 201 Created. 204 No content.
301 Moved Permanently.
400 Bad Request.
401 Unauthorized.
404 Page Not Found.
500 Internal Server Error.
What is NPM? Name some commands.
Node Package Management
install
update
run
uninstall
Describe the Publisher/Subscriber model.
The person who is writing the message (The publisher) does so without knowledge of who is subscribed if anyone.
What is Dependency Injection?
dependency injection - process whereby objects define their dependencies (other objects they work with) through constructor arguments, arguments to a factory method, or properties that are set on the object instance after its constructed or returned from a factory method.
+ the container then injects those dependencies when it creates the bean.
What is the difference between Final, Finalize and Finally?
Final is a keyword that acts as a constant, declaring certain methods, references or classes as immutable.
Finally is associated with the Try-Catch-Finally block; anything declared within the finally block of code will run whether or not an exception is thrown.
Finalize in Garbage Collection -- the last method called on an object before it is garbage collected by the JVM, which is whenever the JVM determines that there is no longer any way in which that object can be accessed.
What is the difference between Safe & Idempotent?
Idempotent means given an input, the response always will have the same output. With safe, you will not affect the data in your database GET, HEAD, OPTIONS are safe. Everything except for POST is idempotent
What are pipes used for?
A pipe is a sort of filter that takes in data, manipulates it and returns different data.
Tell me the Characteristics of RESTful APIs
- Explicit use of HTTP for communication
- Using HTTP status code to identify success or failure of a request.
- Uniform naming convention for defining application endpoints.
- Server processes requests in a stateless manner.
- Use from a variety of data interchange formats (JSON, XML, etc.)
What is AOP? Common uses of AOP?
Spring has its own Aspect-Oriented Programming framework, which is based on AspectJ. Instead of OOP where the key unit of modularity is the class, AOP unit of modularity is the aspect.
Aspects are a modularization of concerns that cuts across multiple classes. Common cross-cutting concerns are logging, security, transaction management.
Aspects are implemented by using regular classes annotated with the @Aspect annotation
What is the hierarchy of Java Collection Framework?
The root interface is Iterable. Collection extends Iterable. Collection has three subclasses: Queue, Stack, and Set. Dequeue extends Queue.
What is the Servlet method signature to handle POST requests?
protected void doPost (HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException)
How does angular routing work?
Must define the path with the routerLink name, and then define the component that it should route to; must also define the list of ROUTES inside of the imports section of the node module
How do you create a SOAP service?
If it's Contract first, you have a WSDL and generate classes from it. Other wise
1. Contract last
@WebService on both
Differences between applicationContext & beanfactory?
Both BeanFactory and ApplicationContext
- can perform bean instantiation/wiring.
ApplicationContext has extra features
- ApplicationEvent publication
- MessageSource access (for internalization).
Its generally recommended that ApplicationContext should be used over BeanFactory for enterprise applications and systems. You would typically only use BeanFactory if the applications memory consumption was critical, and a few extra kilobytes might make a difference.
What is the difference between Error and Exception?
Exceptions are within our control-- checked or unchecked-- contingent upon bad logic or risky code. Errors are beyond the scope of the code, such as running out of memory
Tags found within a web.xml/deployment descriptor
<web-app> <servlet> <servlet-name> <servlet-class> <servlet-mapping> <servlet.name> <url-pattern> <filter> <filter-name> <filter-class>
What are the lifecycle hooks of an Angular component?
ng OnInit (called on initialization)
destroy (called when destroyed)
How do you consume a SOAP service?
Create duplicates of the model that you can get from the wsdl
Create a main method where you create a proxy object that's linked to the soap service
Set service class and endpoint
What are some annotations of Spring?
@Bean
@Configuration
@Controller
@Service
@Repository
@Autowired
@Component
@Qualifer
@SpringBootApplication
@ComponentScan
@EnableAutoConfiguration