Please learn about @SpringBootApplication also

@SpringBootApplication
public class Application {

public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}

}

### 6. Add a main controller

java
package com.example.demo;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MainController {

@GetMapping("/")
public String index() {
return "Hello, World!";
}

}

### 7. Run the application

mvn spring-boot:run
`

### 8. Visit http://localhost:8080

You should see `Hello, World!`

@SpringBootApplication
public class App {

public static void main(String[] args) {
SpringApplication.run(App.class, args);
}

}
</code>
I have created a controller to test the basic rest call :
<code>package com.santhosh.rest.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HomeController {

@GetMapping("/")
public String home() {
return "Welcome to the world of rest";
}

}
</code>
When I hit the url <code>localhost:8080/</code> I am getting below error :
<code>Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Apr 09 11:45:37 IST 2019
There was an unexpected error (type=Not Found, status=404).
No message available
</code>
Please help me to resolve this issue.


A:


verify if your application is running on the port 8080
check your mapping annotation
check if your application is not running multiple instances

if you are using eclipse, you can check the log console for more details about the error

Now you are end to end FullStack dev after completing this many things 😂😂

On Sunday if you guys are available I will conduct one masterclass for end to end FullStack related to the concept not for programming will clear each n every concept with real-time implementation of that particular keyword

Please let me update with your names n batch I will share Google meet link and Google forms

Do work on this part

Because if you are getting below this value u r not really enjoying the upcoming day's

If you are getting issues in voting please leave this channel we don't want sleeper cells here to be active or stay at home don't be in this channel ☺️

Be into competition else have fun

Message me @stockkida for any query or assistance

public class IndexOutOfBoundException {

public static void main(String[] args) {

int[] arr = {1,2,3,4,5};

try {
for(int i = 0; i <= arr.length; i++) {
System.out.println(arr[i]);
}
} catch(ArrayIndexOutOfBoundsException e) {
System.out.println("Index Out Of Bound Exception");
}

}

}

Throw this exception if you don't know the answer

Tomorrow will update you with a link in the evening for java(core java, advance java, Spring and spring boot) n react-js practice test

Just focus on the concept of today's paper

ALGORITHM YOU SHOULD KNOW for PREPARING SYSTEM DESIGN INTERVIEW 💡

🔺REQUIREMENTS :-
KNOW WHEN TO USE
KNOW HOW IT WORKS

◾1) BLOOM FILTER
It is a data structure designed to tell you, rapidly and memory-efficiently, whether an element is present in a set.
- use case :: Build a Web crawler

◾2) FRUGAL STREAMING
It uses only one unit of memory per group to compute a quantile for each group.
-use case :: Find the nth percentile of the data stream.

◾3) GEOHASH/ S2 GEOMETRY
A collection of efficient yet exact mathematical predicates for testing relationships among geometric primitives.
-use case :: Location-based search results with DynamoDb and Geohash.

◾4) HYPERLOGLOG
It is an algorithm for the count-distinct problem, approximating the number of distinct elements in a multiset.
-use case :: privacy-preserving traffic heat map for the city.

◾5) LEAKY BUCKET/ TOKEN BUCKET
A mechanism to control the amount and the rate of the traffic sent to the network.
-use case :: Design a scalable rate-limiting algorithm.

◾6) LOSSY COUNT
It is used to identify elements in a data stream whose frequency count exceeds a user-given threshold.
-use case :: Frequency count over the data streams.

◾7) OPERATIONAL TRANSFORMATION
It is used for supporting a range of collaboration functionalities in advanced collaborative software systems.
-use case :: Handling editing collision in Google docs.

◾8) QUADTREE/ RTREE
It is a two-dimensional analog of octrees and is most often used to partition a two-dimensional space by recursively subdividing it into four quadrants or regions.
-use case :: Find nearby interest points

◾9) RAY CASTING
It is the most basic of many computer graphics rendering algo that uses geometric algo of ray tracing.
-use case :: Using longitude and latitude, return the Country of the point.

◾10) REVERSE INDEX
It is an index of keywords that stores records of documents that contain keywords in the list.
-use case: Building a complete Tweet index.

◾11) RSYNC ALGORITHM
Used for reducing the cost of a file transfer by avoiding the transfer of blocks that are already at the destination.
-use case :: Streaming file Sync

◾12) TRIE ALGORITHM
Trie is an efficient information reTrieval data structure. Using Trie, search complexities can be brought to optimal limit (key length)
-use case :: Autocomplete features using Trie

13) STRING BUFFER
-use case ::  Banking transactions because it follows thread synchronisation

13) STRING BUILDER
-use case ::  BOOKMYSHOW OR IRCTC ticket booking because it NOT following thread synchronisation


collab credit - windsoon / ansh /Aman

#software #design #google #systemdesign #backend #backenddeveloper #softwareengineer #algorithms