# Random Overview #

Q: Difference One-Way SLL and two-way SSL binding?

Answer:

One-way SSL authentication is if the client only verifies the certificate of the server. This validation is done to make sure that it is the expected server, i.e. no man in the middle attack.

Two-way SSL authentication (or better mutual authentication or client authentication) is if the server also verifies the certificate of the client.

2: What is difference between Angular and Angular8?

Initially, Google started by introducing AngularJS in 2012.

AngularJS is based on the Javascript framework while Angular 8 and its versions are typescript frontend web application framework.

Currently, Angular 9 is the latest version.

Let’s see how they are different…

Language:

AngularJS is written in Javascript whereas Angular 8 is a typescript framework.

Mobile Support

AngularJS does not build with mobile support while angular 8 support mobile and desktop application.

Architecture

AngularJS is based on MVC architecture. Angular 8 architecture depends on certain fundamental concepts including the concept of a component-based application.

Now, let’s look at Pros and Cons…

AngularJS

PROS:

• Faster and Scalable Development

• Easy to Use

• Provide Simplest Routing

CONS:

• Javascript Dependent

• Not Secure

Angular 8

PROS:

• Good for single-page web applications

• Reusability

• High Performance

CONS:

• Not SEO Friendly

• Hard to use

• Migration requires lots of time

Both have certain pros & cons. All depends on your requirements. Hopefully, now you have got some idea.

3. What is the difference between simple authentication and Oauth2 Authentication?

4. How to provide security to web services?

Four Ways to Secure RESTful Web Services

·         2.1. BASIC Authentication. It’s simplest of all techniques and probably most used as well. You use login/password forms...

·         2.2. DIGEST Authentication. This authentication method makes use of a hashing algorithms to encrypt the password (called...

·         2.3. Client CERT Authentication. This is a mechanism in which a trust agreement is established between the server and...

·         2.4. OAUTH2 API Keys. If you have ever developed applications which interact other with other applications over...

Difference between Basic Authentication and OAUTH2 Authentication?

1^st Answer:

Yes, they both are different.

Http Basic:

This is for authentication and user credentials are encoded then passed in HTTP header to the client server. Basic example for HTTP Basic: Just like traditional web application which asked user to provide credentials and these credentials sent to server in HTTP header. Later server utilize those credentials to authenticate the user.

OAuth 2 :

This is for authorization, here the client server required authorization of user data(resource owner) from authorization server. Basic example for OAuth 2 : Let say there is a online game application running on a server, the user accessed the application which starts loading into user's browser. Now that application asking grants from user to post data about games on his Facebook account. Here user authorize his that application to access his Facebook posts through OAuth Standard. Refer the internal mechanism https://tools.ietf.org/html/rfc6749

2^ND Answer:

Basic access authentication usage is comparable to OAuth 2.0 Client Credentials Grant Type.

A session can be created using Basic Authentication and services can be accessed using a sessionid in a stateful environment.

But if you do not want to use the session due to session limitations or stateless services, you can use the OAuth 2.0 Client Credentials Grant Type instead, which creates a token instead of session and sessionid. This token provides access to the services.

5. In Spring Boot why we deploy jar file not a war files?

Differences between jar and war in Spring Boot?

14

Spring Boot can be told to produce a 'fat JAR' which includes all of your module/service's dependencies and can be run with java -jar <your jar>. See "Create an executable JAR with Maven" here.

Spring Boot can also be told to produce a WAR file, in which case you'll likely choose to deploy it to a web container such as Tomcat or Jetty.

Plenty more details on Spring Boot deployment here.

9

Depends on your deployment. If you are planning to deploy your application to an existing Java EE Application Server (e.g. Tomcat), then standard approach is to perform a war build.

When you use fat jar approach, your application will be deployed on embedded application container provided by spring boot. Conduct Deploying Spring Boot Applications for more information.

Running spring-boot application as fat *.jar

It is possible to build so called fat JAR that is executable *.jar file with embedded application container (Tomcat as default option). There are spring-boot plugins for various build systems. Here is the one for maven: spring-boot-maven-plugin

To execute the kind of fat *.jar you could simple run command:

java -jar *.jar

Or using spring-boot-maven goal:

mvn spring-boot: run

 

Building spring-boot application as *.war archive

The other option is to ship your application as old-fashioned war file. It could be deployed to any servlet container out there. Here is step by step how-to list:

1.    Change packaging to war (talking about maven's pom.xml)

2.    Inherit main spring-boot application class from SpringBootServletInitializer and override SpringApplicationBuilder configure(SpringApplicationBuilder) method (see javadoc)

3.    Make sure to set the scope of spring-boot-starter-tomcat as provided

One-sentence definitions of OAuth 2.0 and OpenID Connect

OAuth 2.0 is a framework where a user of a service can allow a third-party application to access his/her data hosted in the service without revealing his/her credentials (ID & password) to the application.

OpenID Connect is a framework on top of OAuth 2.0 where a third-party application can obtain a user's identity information which is managed by a service.

^{(Sorry, these definitions are excerpts from the overview page of my company)}

What is Cross-Site –Scripting?

Cross-Site Scripting is an attack on the web security of the user, the main motive of the attacker is to steal the data of the user by running a malicious script in the browser that is injected in the website content which is used by the user, as a result of this attack, the attacker gains full control of the victims browser which he can use to browse and send the worm to the user computer, this attack is classified into two categories i.e. Stored XSS attack and Procedure XSS attack.

Question: How to sort the object using Lanbda using Java1.8 ?

Solution :

https://www.javaguides.net/2020/04/java-8-lambda-sort-list-in-ascending-and-descending-order.html

Sort List of Employee Objects in Ascending and Descending Order using Lambda Expressions

In this example, we will see how to sort a list of employees by name in ascending and descending order using Lambda Expressions:

package com.java.tutorials.sorting;

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.List;

public class SortList {

    public static void main(String[] args) {

        List < Employee > employees = new ArrayList < Employee > ();

        employees.add(new Employee(10, "Ramesh", 30, 400000));

        employees.add(new Employee(20, "Santosh", 29, 350000));

        employees.add(new Employee(30, "Sanjay", 30, 450000));

        employees.add(new Employee(40, "Pramod", 29, 500000));

        Collections.sort(employees, new Comparator < Employee > () {

            @Override

            public int compare(Employee o1, Employee o2) {

                return (int)(o1.getName().compareTo(o2.getName()));

            }

        });

        // using lambda expression

        // ascending order

        Collections.sort(employees, (o1, o2) - > (o1.getName().compareTo(o2.getName())));

        System.out.println("Ascending order => " + employees);

        // descending order

        Collections.sort(employees, (o1, o2) - > (o2.getName().compareTo(o1.getName())));

        System.out.println("Descending order => " + employees);

        // using Comparator.comparing() method

        Collections.sort(employees, Comparator.comparing(Employee::getName));

    }

}

class MySort implements Comparator < Employee > {

    @Override

    public int compare(Employee o1, Employee o2) {

        return (int)(o1.getSalary() - o2.getSalary());

    }

}

Note that the lambda expression we used to sort List of employees:

 // using lambda expression

        // ascending order

        Collections.sort(employees, (o1, o2) - > (o1.getName().compareTo(o2.getName())));

        System.out.println("Ascending order => " + employees);

        // descending order

        Collections.sort(employees, (o1, o2) - > (o2.getName().compareTo(o1.getName())));

        System.out.println("Descending order => " + employees);

Output:

Ascending order => [Employee [id=40, name=Pramod, age=29, salary=500000], Employee [id=10, name=Ramesh, age=30, salary=400000], Employee [id=30, name=Sanjay, age=30, salary=450000], Employee [id=20, name=Santosh, age=29, salary=350000]]

Descending order => [Employee [id=20, name=Santosh, age=29, salary=350000], Employee [id=30, name=Sanja

Question :SOAP message Format?

Answer:

·        Envelope − Defines the start and the end of the message. It is a mandatory element.

·        Header − Contains any optional attributes of the message used in processing the message, either at an intermediary point or at the ultimate end-point. It is an optional element.

·        Body − Contains the XML data comprising the message being sent. It is a mandatory element.

·        Fault − An optional Fault element that provides information about errors that occur while processing the message.

Question: Difference between Interface and Abstract class?

Question : What is difference between GROUPID & Artifact ID?

The main difference between groupId and artifactId in Maven is that the groupId specifies the id of the project group while the artifactId specifies the id of the project.

It is required to use third party libraries when developing a project. The programmer can download and add these third-party libraries to the project, but it is difficult to update them later. Maven provides a solution to this issue. It helps to include all the dependencies required for the project. Moreover, the programmer can specify the required dependencies in the POM.XML file. It has the configuration information to build the project. Furthermore, this file consists of several XML elements, and two of them are groupId and artifactId.