My First Commit

.gitignore

+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/

.mvn/wrapper/maven-wrapper.properties

+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.6/apache-maven-3.8.6-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar

mvnw.cmd

+@REM ----------------------------------------------------------------------------
+@REM Licensed to the Apache Software Foundation (ASF) under one
+@REM or more contributor license agreements.  See the NOTICE file
+@REM distributed with this work for additional information
+@REM regarding copyright ownership.  The ASF licenses this file
+@REM to you under the Apache License, Version 2.0 (the
+@REM "License"); you may not use this file except in compliance
+@REM with the License.  You may obtain a copy of the License at
+@REM
+@REM    https://www.apache.org/licenses/LICENSE-2.0
+@REM
+@REM Unless required by applicable law or agreed to in writing,
+@REM software distributed under the License is distributed on an
+@REM "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+@REM KIND, either express or implied.  See the License for the
+@REM specific language governing permissions and limitations
+@REM under the License.
+@REM ----------------------------------------------------------------------------
+
+@REM ----------------------------------------------------------------------------
+@REM Maven Start Up Batch script
+@REM
+@REM Required ENV vars:
+@REM JAVA_HOME - location of a JDK home dir
+@REM
+@REM Optional ENV vars
+@REM M2_HOME - location of maven2's installed home dir
+@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
+@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a keystroke before ending
+@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
+@REM     e.g. to debug Maven itself, use
+@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+@REM MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+@REM ----------------------------------------------------------------------------
+
+@REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
+@echo off
+@REM set title of command window
+title %0
+@REM enable echoing by setting MAVEN_BATCH_ECHO to 'on'
+@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+
+@REM set %HOME% to equivalent of $HOME
+if "%HOME%" == "" (set "HOME=%HOMEDRIVE%%HOMEPATH%")
+
+@REM Execute a user defined script before this one
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+@REM check for pre script, once with legacy .bat ending and once with .cmd ending
+if exist "%USERPROFILE%\mavenrc_pre.bat" call "%USERPROFILE%\mavenrc_pre.bat" %*
+if exist "%USERPROFILE%\mavenrc_pre.cmd" call "%USERPROFILE%\mavenrc_pre.cmd" %*
+:skipRcPre
+
+@setlocal
+
+set ERROR_CODE=0
+
+@REM To isolate internal variables from possible post scripts, we use another setlocal
+@setlocal
+
+@REM ==== START VALIDATION ====
+if not "%JAVA_HOME%" == "" goto OkJHome
+
+echo.
+echo Error: JAVA_HOME not found in your environment. >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+:OkJHome
+if exist "%JAVA_HOME%\bin\java.exe" goto init
+
+echo.
+echo Error: JAVA_HOME is set to an invalid directory. >&2
+echo JAVA_HOME = "%JAVA_HOME%" >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+@REM ==== END VALIDATION ====
+
+:init
+
+@REM Find the project base dir, i.e. the directory that contains the folder ".mvn".
+@REM Fallback to current working directory if not found.
+
+set MAVEN_PROJECTBASEDIR=%MAVEN_BASEDIR%
+IF NOT "%MAVEN_PROJECTBASEDIR%"=="" goto endDetectBaseDir
+
+set EXEC_DIR=%CD%
+set WDIR=%EXEC_DIR%
+:findBaseDir
+IF EXIST "%WDIR%"\.mvn goto baseDirFound
+cd ..
+IF "%WDIR%"=="%CD%" goto baseDirNotFound
+set WDIR=%CD%
+goto findBaseDir
+
+:baseDirFound
+set MAVEN_PROJECTBASEDIR=%WDIR%
+cd "%EXEC_DIR%"
+goto endDetectBaseDir
+
+:baseDirNotFound
+set MAVEN_PROJECTBASEDIR=%EXEC_DIR%
+cd "%EXEC_DIR%"
+
+:endDetectBaseDir
+
+IF NOT EXIST "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto endReadAdditionalConfig
+
+@setlocal EnableExtensions EnableDelayedExpansion
+for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
+@endlocal & set JVM_CONFIG_MAVEN_PROPS=%JVM_CONFIG_MAVEN_PROPS%
+
+:endReadAdditionalConfig
+
+SET MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
+set WRAPPER_JAR="%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.jar"
+set WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
+
+FOR /F "usebackq tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
+    IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B
+)
+
+@REM Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+@REM This allows using the maven wrapper in projects that prohibit checking in binary data.
+if exist %WRAPPER_JAR% (
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Found %WRAPPER_JAR%
+    )
+) else (
+    if not "%MVNW_REPOURL%" == "" (
+        SET DOWNLOAD_URL="%MVNW_REPOURL%/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
+    )
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Couldn't find %WRAPPER_JAR%, downloading it ...
+        echo Downloading from: %DOWNLOAD_URL%
+    )
+
+    powershell -Command "&{"^
+		"$webclient = new-object System.Net.WebClient;"^
+		"if (-not ([string]::IsNullOrEmpty('%MVNW_USERNAME%') -and [string]::IsNullOrEmpty('%MVNW_PASSWORD%'))) {"^
+		"$webclient.Credentials = new-object System.Net.NetworkCredential('%MVNW_USERNAME%', '%MVNW_PASSWORD%');"^
+		"}"^
+		"[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; $webclient.DownloadFile('%DOWNLOAD_URL%', '%WRAPPER_JAR%')"^
+		"}"
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Finished downloading %WRAPPER_JAR%
+    )
+)
+@REM End of extension
+
+@REM Provide a "standardized" way to retrieve the CLI args that will
+@REM work with both Windows and non-Windows executions.
+set MAVEN_CMD_LINE_ARGS=%*
+
+%MAVEN_JAVA_EXE% ^
+  %JVM_CONFIG_MAVEN_PROPS% ^
+  %MAVEN_OPTS% ^
+  %MAVEN_DEBUG_OPTS% ^
+  -classpath %WRAPPER_JAR% ^
+  "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" ^
+  %WRAPPER_LAUNCHER% %MAVEN_CONFIG% %*
+if ERRORLEVEL 1 goto error
+goto end
+
+:error
+set ERROR_CODE=1
+
+:end
+@endlocal & set ERROR_CODE=%ERROR_CODE%
+
+if not "%MAVEN_SKIP_RC%"=="" goto skipRcPost
+@REM check for post script, once with legacy .bat ending and once with .cmd ending
+if exist "%USERPROFILE%\mavenrc_post.bat" call "%USERPROFILE%\mavenrc_post.bat"
+if exist "%USERPROFILE%\mavenrc_post.cmd" call "%USERPROFILE%\mavenrc_post.cmd"
+:skipRcPost
+
+@REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
+if "%MAVEN_BATCH_PAUSE%"=="on" pause
+
+if "%MAVEN_TERMINATE_CMD%"=="on" exit %ERROR_CODE%
+
+cmd /C exit /B %ERROR_CODE%

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.7.1</version>
+		<relativePath/> <!-- lookup parent from repository -->
+	</parent>
+	<groupId>com.example.reactor</groupId>
+	<artifactId>Project-Reactor</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>Project-Reactor</name>
+	<description>Demo project for Spring Boot</description>
+	<properties>
+		<java.version>1.8</java.version>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-data-mongodb-reactive</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-webflux</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-devtools</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	<!--	<dependency>
+			<groupId>de.flapdoodle.embed</groupId>
+			<artifactId>de.flapdoodle.embed.mongo</artifactId>
+			<scope>test</scope>
+		</dependency>-->
+		<dependency>
+			<groupId>io.projectreactor</groupId>
+			<artifactId>reactor-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<excludes>
+						<exclude>
+							<groupId>org.projectlombok</groupId>
+							<artifactId>lombok</artifactId>
+						</exclude>
+					</excludes>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

src/main/java/com/example/reactor/ProjectReactor/ProjectReactorApplication.java

+package com.example.reactor.ProjectReactor;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ProjectReactorApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(ProjectReactorApplication.class, args);
+	}
+
+}

src/main/java/com/example/reactor/ProjectReactor/config/MongoDBConfig.java

+/*
+package com.example.reactor.ProjectReactor.config;
+
+import com.mongodb.reactivestreams.client.MongoClient;
+import com.mongodb.reactivestreams.client.MongoClients;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import org.springframework.data.mongodb.config.AbstractReactiveMongoConfiguration;
+import org.springframework.data.mongodb.core.ReactiveMongoTemplate;
+import org.springframework.data.mongodb.repository.config.EnableMongoRepositories;
+
+@Configuration
+@EnableMongoRepositories(basePackages = "com.example.reactor.ProjectReactor.repository")
+public class MongoDBConfig extends AbstractReactiveMongoConfiguration {
+    @Value("{mongodb.database.name}")
+    private String databaseName;
+    @Value("{mongodb.database.host}")
+    private String databaseHost;
+
+    @Override
+    protected String getDatabaseName() {
+        return databaseName;
+    }
+
+    @Override
+    public MongoClient reactiveMongoClient() {
+        String name = databaseHost;
+        return MongoClients.create(name);
+    }
+
+    @Bean
+    public ReactiveMongoTemplate reactiveMongoTemplate(){
+        return new ReactiveMongoTemplate(reactiveMongoClient(),getDatabaseName());
+    }
+
+}
+*/

src/main/java/com/example/reactor/ProjectReactor/controller/ContactController.java

+package com.example.reactor.ProjectReactor.controller;
+
+import com.example.reactor.ProjectReactor.entity.Contact;
+import com.example.reactor.ProjectReactor.repository.ContactRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+@RestController
+@RequestMapping("/api/contact")
+@RequiredArgsConstructor
+public class ContactController {
+
+    @Autowired
+    private ContactRepository contactRepository;
+
+    @PostMapping(value = "/save")
+    private Mono<ResponseEntity<Contact>> saveContact(@RequestBody Contact contact) {
+        Mono<ResponseEntity<Contact>> responseEntityMono = contactRepository.insert(contact)
+                .map(c1 -> new ResponseEntity<>(c1, HttpStatus.ACCEPTED))
+                .defaultIfEmpty(new ResponseEntity<>(HttpStatus.NOT_ACCEPTABLE));
+        return responseEntityMono;
+    }
+
+    @GetMapping(value = "/all")
+    private Flux<Contact> getAllContact() {
+        Flux<Contact> all = contactRepository.findAll();
+        return all;
+    }
+
+    @GetMapping(value = "/get/{id}")
+    private Mono<ResponseEntity<Contact>> getContactById(@PathVariable String id) {
+        return contactRepository.findById(id)
+                .map(c -> new ResponseEntity<>(c, HttpStatus.OK))
+                .defaultIfEmpty(new ResponseEntity<>(HttpStatus.NOT_FOUND));
+    }
+
+    @DeleteMapping(value = "/delete/{id}")
+    private Mono<Void> deleteById(@PathVariable String id) {
+        return contactRepository.deleteById(id);
+    }
+
+    @GetMapping(value = "/get/email")
+    private Mono<ResponseEntity<Contact>> findByEmail(@RequestParam("email") String email) {
+        return contactRepository.findFirstByEmail(email)
+                .map(c -> new ResponseEntity<>(c, HttpStatus.FOUND))
+                .defaultIfEmpty(new ResponseEntity<>(HttpStatus.NOT_FOUND));
+    }
+
+    @PutMapping(value = "/update/{id}")
+    private Mono<ResponseEntity<Contact>> updateContact(@RequestBody Contact contact, @PathVariable String id) {
+        return contactRepository.findById(id).flatMap(c -> {
+            contact.setId(id);
+            return contactRepository.save(contact)
+                    .map(c1 -> new ResponseEntity<>(c1, HttpStatus.OK))
+                    .defaultIfEmpty(new ResponseEntity<>(HttpStatus.NOT_FOUND));
+        });
+    }
+
+}

src/main/java/com/example/reactor/ProjectReactor/entity/Contact.java

+package com.example.reactor.ProjectReactor.entity;
+
+import lombok.*;
+import org.springframework.data.annotation.Id;
+import org.springframework.data.mongodb.core.mapping.Document;
+
+@Document
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+@Builder
+public class Contact {
+
+    @Id
+    private String id;
+    private String name;
+    private String email;
+    private String phone;
+
+}

src/main/java/com/example/reactor/ProjectReactor/repository/ContactRepository.java

+package com.example.reactor.ProjectReactor.repository;
+
+import com.example.reactor.ProjectReactor.entity.Contact;
+import org.springframework.data.mongodb.repository.ReactiveMongoRepository;
+import org.springframework.stereotype.Repository;
+import reactor.core.publisher.Mono;
+
+@Repository
+public interface ContactRepository extends ReactiveMongoRepository<Contact,String> {
+    Mono<Contact> findFirstByEmail(String email);
+
+    //Mono<Contact> findAllByPhoneOrName(String phoneOrName);
+}

src/main/resources/application.properties

+server.port=8090
+#mongodb.database.name=Contact
+#mongodb.database.host=mongodb://localhost:27017/
+
+spring.data.mongodb.uri=mongodb://localhost:27017/Contact
+

src/test/java/com/example/reactor/ProjectReactor/ContactControllerTest.java

+package com.example.reactor.ProjectReactor;
+
+import com.example.reactor.ProjectReactor.entity.Contact;
+import org.junit.jupiter.api.*;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.reactive.AutoConfigureWebTestClient;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.web.reactive.function.BodyInserters;
+import reactor.core.publisher.Flux;
+import reactor.test.StepVerifier;
+
+@SpringBootTest
+@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+@AutoConfigureWebTestClient
+@ActiveProfiles("unit_test")
+public class ContactControllerTest {
+
+    @Autowired
+    private WebTestClient webTestClient;
+
+    Contact contact;
+
+    @Test
+    @Order(1)
+    public void createContact() {
+        Flux<Contact> saveFlux = webTestClient
+                .post()
+                .uri("/api/contact/save")
+                .contentType(MediaType.APPLICATION_JSON)
+                .body(BodyInserters.fromValue(new Contact("1", "Ravi", "Ravi@gmail.com", "352323")))
+                .exchange()
+                .expectStatus().isAccepted()
+                .returnResult(Contact.class).getResponseBody().log();
+
+        saveFlux.next().subscribe(c -> {
+            this.contact = c;
+        });
+
+        Assertions.assertNotNull(contact);
+    }
+
+    @Test
+    @Order(2)
+    public void getByEmail() {
+        Flux<Contact> getByEmail = webTestClient.get().uri("/api/contact/get/email?email={email}", "Ravi@gmail.com")
+                .accept(MediaType.APPLICATION_JSON)
+                .exchange()
+                .expectStatus().isFound().
+                returnResult(Contact.class).getResponseBody().log();
+
+        StepVerifier.create(getByEmail).expectSubscription().expectNextMatches(c -> c.getPhone().equals("45475434")).verifyComplete();
+    }
+
+   /* @Test
+    @Order(3)
+    public void updateContact() {
+        Flux<Contact> updateFlux = webTestClient.put().uri("/api/contact/update/{id}", contact.getId()).accept(MediaType.APPLICATION_JSON)
+                .body(BodyInserters.fromValue(new Contact("WebTestClient", "wtc@email.com", "11111111").setId(contact.getId())))
+                .exchange()
+                .returnResult(Contact.class).getResponseBody().log();
+
+        StepVerifier.create(updateFlux).expectSubscription().expectNextMatches(c -> c.getEmail().equals("wtc@email.com")).verifyComplete();
+    }*/
+
+
+}

src/test/java/com/example/reactor/ProjectReactor/ContactReposityTest.java

+package com.example.reactor.ProjectReactor;
+
+import com.example.reactor.ProjectReactor.entity.Contact;
+import com.example.reactor.ProjectReactor.repository.ContactRepository;
+import org.junit.jupiter.api.*;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.data.mongodb.core.ReactiveMongoOperations;
+import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
+
+@SpringBootTest
+@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+public class ContactReposityTest {
+
+    @Autowired
+    private ContactRepository contactRepository;
+
+    @Autowired
+    private ReactiveMongoOperations reactiveMongoOperations;
+
+    @BeforeAll
+    public void insertData() {
+
+        Contact c = new Contact();
+        c.setName("Raja");
+        c.setEmail("Raja@gmail.com");
+        c.setPhone("7546");
+
+        Contact c1 = new Contact();
+        c1.setName("Revan");
+        c1.setEmail("Revan@gmail.com");
+        c1.setPhone("12324");
+
+        Contact c2 = new Contact();
+        c2.setName("Arya");
+        c2.setEmail("Arya@gmail.com");
+        c2.setPhone("534646");
+
+       /* Contact c3 = new Contact();
+        c3.setName("Raja");
+        c3.setEmail("Raja@gmail.com");
+        c3.setPhone("7546");
+
+        Contact c4 = new Contact();
+        c4.setName("Raja");
+        c4.setEmail("Raja@gmail.com");
+        c4.setPhone("7546");*/
+
+        StepVerifier.create(contactRepository.insert(c).log()).expectSubscription().expectNextCount(1).verifyComplete();
+
+        StepVerifier.create(contactRepository.save(c1).log()).expectSubscription().expectNextCount(1).verifyComplete();
+
+        StepVerifier.create(contactRepository.save(c2).log()).expectSubscription().expectNextMatches(a -> a.getId() != null).verifyComplete();
+    }
+
+    @Test
+    @Order(1)
+    public void findAll() {
+        StepVerifier.create(contactRepository.findAll().log()).expectSubscription().expectNextCount(4).expectComplete();
+    }
+
+    @Test
+    @Order(2)
+    public void findByEmail() {
+        StepVerifier.create(contactRepository.findFirstByEmail("Arya@gmail.com").log()).expectSubscription().expectNextCount(1).verifyComplete();
+    }
+
+    @Test
+    @Order(3)
+    public void updateContact() {
+        Mono<Contact> firstByEmail = contactRepository.findFirstByEmail("Arya@gmail.com")
+                .map(c -> {
+                    c.setPhone("11111");
+                    return c;
+                }).flatMap(c1 -> contactRepository.save(c1));
+        StepVerifier.create(firstByEmail.log()).expectSubscription().expectNextMatches(c -> c.getPhone().equals("11111")).verifyComplete();
+    }
+
+    @Test
+    @Order(4)
+    public void deleteContact() {
+        Mono<Void> firstByEmail = contactRepository.findFirstByEmail("Arya@gmail.com").flatMap(c1 -> {
+            return contactRepository.deleteById(c1.getId());
+        }).log();
+
+        StepVerifier.create(firstByEmail).expectSubscription().verifyComplete();
+
+    }
+
+}

src/test/java/com/example/reactor/ProjectReactor/ErrorSample.java

+package com.example.reactor.ProjectReactor;
+
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.data.mongodb.core.aggregation.ArrayOperators;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import sun.reflect.annotation.ExceptionProxy;
+
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+@SpringBootTest
+public class ErrorSample {
+
+    Logger log = LoggerFactory.getLogger(ErrorSample.class);
+
+    @Test
+    public void onErrorReturnDirectly_Mono() {
+        Mono.
+                just(2).
+                map(i -> i / 0). //Arthimetic Exception
+                onErrorReturn(0).
+                subscribe(num -> System.out.println("Number after exception--->" + num));
+    }
+
+    /*
+    type – the error type to match
+    fallbackValue – the value to emit if an error occurs that matches the type
+     */
+    @Test
+    public void onErrorReturnExceptionTypeMatched_Mono() {
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorReturn(ArithmeticException.class, 0)
+                .subscribe(num -> System.out.println("ExceptionTypeMatched--->" + num));
+    }
+
+    /*
+        predicate – the error predicate to match
+        fallbackValue – the value to emit if an error occurs that matches the predicate
+     */
+
+    @Test
+    public void onErrorReturnPredicateValueMatched_Mono() {
+
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorReturn(error -> error instanceof ArithmeticException, 0)
+                .subscribe(num -> System.out.println("Predicate Value matched--->" + num));
+    }
+
+    /*
+    Params: fallback – the function to choose the fallback to an alternative Mono
+    Returns: a Mono falling back upon source onError
+     */
+    @Test
+    public void onErrorResumeDefault_Mono() {
+        //Function<Throwable, Mono<Integer>> function = error -> Mono.just(4);
+        Function<Throwable, Mono<Integer>> function = error -> Mono.error(new RuntimeException("Exceptions occurred"));
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorResume(function)
+                .subscribe(num -> System.out.println("Error Occured pass another function" + num));
+    }
+
+    /*
+    Params:type – the error type to match fallback – the function to choose the fallback to an alternative Mono
+    Returns:a Mono falling back upon source onError
+     */
+    @Test
+    public void onErrorResumeExceptionTypeMatched_Mono() {
+        Function<Throwable, Mono<Integer>> function = error -> Mono.just(4);
+        Mono
+                .just(2)
+                .map(i -> i / 0)
+                .onErrorResume(ArithmeticException.class, function)
+                .subscribe(num -> System.out.println("Exception type matched--->" + num));
+    }
+
+    /*
+    Params:predicate – the error predicate to match fallback – the function to choose the fallback to an alternative Mono
+    Returns:a Mono falling back upon source onError
+     */
+
+    @Test
+    public void onErrorResumePredicateMatched_Mono() {
+        Function<Throwable, Mono<Integer>> function = error -> Mono.just(4);
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorResume(error -> error instanceof ArithmeticException, function)
+                .subscribe(num -> System.out.println("Predicate Matched--->" + num));
+
+    }
+
+    /*
+     param errorConsumer a {@link BiConsumer} fed with errors matching the {@link Class} and the value that triggered the error.
+	 return a {@link Mono} that attempts to continue processing on errors
+     */
+    @Test
+    public void onErrorContinueDefault_Mono() {
+        BiConsumer<Throwable, Object> biConsumer = (e, i) -> {
+            System.out.println("Error-->" + e + "----> Value" + i);
+        };
+        Mono.just(2).map(i -> i / 0).onErrorContinue(biConsumer).subscribe(num -> System.out.println("onErrorContinue--->" + num));
+
+    }
+
+    /*
+    Params:type – the Class of Exception that are resumed from. errorConsumer – a BiConsumer fed with errors matching the Class and the value that triggered the error.
+    Returns:a Mono that attempts to continue processing on some errors.
+     */
+    @Test
+    public void onErrorContinueExceptionClassMatched_Mono() {
+        BiConsumer<Throwable, Object> biConsumer = (e, i) -> {
+            System.out.println("Error-->" + e + "----> Value" + i);
+        };
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorContinue(ArithmeticException.class, biConsumer)
+                .subscribe(num -> System.out.println(num));
+    }
+
+    /*
+    Params:errorPredicate – a Predicate used to filter which errors should be resumed from. This MUST be idempotent, as it can be used several times. errorConsumer – a BiConsumer fed with errors matching the predicate and the value that triggered the error.
+    Returns:a Mono that attempts to continue processing on some errors.
+     */
+    @Test
+    public void onErrorContinuePredicateMatched_Mono() {
+        BiConsumer<Throwable, Object> biConsumer = (e, i) -> {
+            System.out.println("Error-->" + e + " Value--->" + i);
+        };
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorContinue(error -> error instanceof ArithmeticException, biConsumer)
+                .subscribe(s -> System.out.println(s));
+    }
+
+    /*
+    param onError the error callback to call on {@link Subscriber#onError(Throwable)}
+
+	  return a new {@link Mono}
+     */
+    @Test
+    public void doOnError_Mono() {
+        Consumer<Throwable> consumer = (error) -> {
+            log.info("caught error");
+        };
+        Mono.just(2)
+                .map(i -> i / 0) // will produce ArithmeticException
+                .doOnError(consumer)
+                .onErrorResume(e -> Mono.empty())
+                .subscribe(num -> log.info("Number: {}", num));
+    }
+
+    /*
+     @param exceptionType the type of exceptions to handle
+	 @param onError the error handler for relevant errors
+	 @param <E> type of the error to handle
+
+	 @return an observed  {@link Mono}
+     */
+    @Test
+    public void doOnErrorIfArithmeticException_Mono() {
+        Mono.just(2)
+                .map(i -> i / 0) // will produce ArithmeticException
+                .doOnError(
+                        ArithmeticException.class,
+                        error -> log.info("caught error")
+                ).onErrorResume(e -> Mono.empty())
+                .subscribe(num -> log.info("Number: {}", num));
+    }
+
+    /*
+    Params:predicate – the matcher for exceptions to handle onError – the error handler for relevant error
+    Returns:an observed Mono
+     */
+
+    @Test
+    public void doOnErrorIfPredicatePasses_Mono() {
+        Mono.just(2)
+                .map(i -> i / 0) // will produce ArithmeticException
+                .doOnError(
+                        error -> error instanceof ArithmeticException,
+                        System.err::println
+                ).onErrorResume(e -> Mono.empty())
+                .subscribe(num -> log.info("Number: {}", num));
+    }
+
+    /*
+    Params:mapper – the error transforming Function
+    Returns:a Mono that transforms source errors to other errors
+     */
+    @Test
+    public void onErrorMap_Mono() {
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorMap(e -> new RuntimeException("2 is not divisible by 0"))
+                .subscribe(n -> System.out.println("Number -->" + n));
+    }
+
+    /*
+    Params:type – the class of the exception type to react to mapper – the error transforming Function
+    Returns:a Mono that transforms some source errors to other erro
+     */
+    @Test
+    public void onErrorMapExceptionMatched_Mono() {
+        Mono.just(2)
+                .map(i -> i / 0)
+                .onErrorMap(ArithmeticException.class, e -> new RuntimeException(" number is not divisible by 0"))
+                .subscribe(n -> System.out.println(n));
+    }
+
+    @Test
+    public void onErrorMapPredicateMatch_mono() {
+        Mono.just(2).map(i -> i / 0)
+                .onErrorMap(error -> error instanceof ArrayIndexOutOfBoundsException, e -> new Exception("Number is not divisible by 0"))
+                .subscribe(num -> System.out.println(num));
+    }
+
+    @Test
+    public void onErrorMapPredicateMatch_Flux(){
+        Flux.just(2,0,1).map(i->i/0)
+                .onErrorMap(ArithmeticException.class, e -> new RuntimeException(" number is not divisible by 0"))
+                .subscribe(n -> System.out.println("Num-->"+n));
+    }
+
+}

src/test/java/com/example/reactor/ProjectReactor/FluxTest.java

+package com.example.reactor.ProjectReactor;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import reactor.core.publisher.Flux;
+import reactor.test.StepVerifier;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+@SpringBootTest
+public class FluxTest {
+
+    private static List<String> words = Arrays.asList(
+            "the",
+            "quick",
+            "brown",
+            "fox",
+            "jumped",
+            "over",
+            "the",
+            "lazy",
+            "dog"
+    );
+
+    @Test
+    public void concatenateFlux() {
+        Flux<Integer> evenFlux = Flux.range(1, 5).filter(x -> x % 2 == 0);
+        Flux<Integer> oddFlux = Flux.range(1, 6).filter(x -> x % 2 != 0);
+        Flux<Integer> concat = Flux.concat(evenFlux, oddFlux);
+
+        StepVerifier.create(concat.log())
+                .expectSubscription()
+                .expectNext(2)
+                .expectNext(4)
+                .expectNext(1)
+                .expectNext(3)
+                .expectNext(5)
+                .verifyComplete();
+    }
+
+    @Test
+    public void concatenateWithFlux() {
+        Flux<Integer> evenFlux = Flux.range(1, 5).filter(x -> x % 2 == 0);
+        Flux<Integer> oddFlux = Flux.range(1, 6).filter(x -> x % 2 != 0);
+
+        Flux<Integer> integerFlux = evenFlux.concatWith(oddFlux);
+
+        StepVerifier.create(integerFlux.log())
+                .expectSubscription()
+                .expectNext(2)
+                .expectNext(4)
+                .expectNext(1)
+                .expectNext(3)
+                .expectNext(5)
+                .verifyComplete();
+    }
+
+
+    @Test
+    public void combineLatest() {
+        Flux<Integer> evenFlux = Flux.range(1, 5).filter(x -> x % 2 == 0);
+        Flux<Integer> oddFlux = Flux.range(1, 6).filter(x -> x % 2 != 0);
+        Flux<Integer> combineLatestFlux = Flux.combineLatest(evenFlux, oddFlux, (a, b) -> a + b);
+
+        StepVerifier.create(combineLatestFlux.log())
+                .expectSubscription()
+                .expectNext(5)
+                .expectNext(7)
+                .expectNext(9)
+                .verifyComplete();
+    }
+
+    @Test
+    public void merge() {
+        Flux<Integer> evenFlux = Flux.range(1, 5).filter(x -> x % 2 == 0);
+        Flux<Integer> oddFlux = Flux.range(1, 6).filter(x -> x % 2 != 0);
+        Flux<Integer> combineLatestFlux = Flux.merge(evenFlux, oddFlux);
+
+        StepVerifier.create(combineLatestFlux.log())
+                .expectSubscription()
+                .expectNext(2)
+                .expectNext(4)
+                .expectNext(1)
+                .expectNext(3)
+                .expectNext(5)
+                .verifyComplete();
+    }
+
+    @Test
+    public void zip() {
+        Flux<Integer> evenFlux = Flux.range(1, 5).filter(x -> x % 2 == 0);
+        Flux<Integer> oddFlux = Flux.range(1, 6).filter(x -> x % 2 != 0);
+        //Flux<Integer> primeFlux = Flux.range(1, 5).filter(x -> x % 3 == 0);
+        Flux<Integer> zip = Flux.zip(evenFlux, oddFlux, (a, b) -> a + b);
+
+        StepVerifier.create(zip)
+                .expectSubscription()
+                .expectNext(3)
+                .expectNext(7)
+                .verifyComplete();
+    }
+
+    @Test
+    public void verifyNextAs2() {
+        final List<Integer> source = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+        Flux<Integer> flux = Flux.fromStream(source.stream());
+        StepVerifier.create(flux.log())
+                .expectNextSequence(source)
+                .expectComplete()
+                .verify();
+    }
+
+    @Test
+    public void sampleCreation(){
+        Flux<String> just = Flux.just("Ravi", "Rajesh");
+        Flux<String> stringFlux = Flux.fromIterable(words);
+
+        just.subscribe(System.out::println);
+        stringFlux.subscribe(System.out::println);
+    }
+
+    @Test
+    public void findingMissingLetters(){
+        Flux<String> sort = Flux.fromIterable(words)
+                .flatMap(word -> Flux.fromArray(word.split("")))
+                .distinct()
+                .sort()
+                .zipWith(Flux.range(1,Integer.MAX_VALUE),(string,count)->String.format("%2d,%s",count,string));
+        sort.subscribe(System.out::println);
+    }
+
+    @Test
+    public void fluxToList(){
+        Flux<String> just = Flux.just("Ravi", "Pannala", "Reddy");
+        List<String> wordsList = new ArrayList<>();
+        just.collectList().subscribe(wordsList::addAll);
+        wordsList.forEach(System.out::println);
+
+        just.collectMap(
+                item -> item.split(":")[0],
+                item -> item.split(":")[1]);
+    }
+
+}

src/test/java/com/example/reactor/ProjectReactor/MonoSample.java

+package com.example.reactor.ProjectReactor;
+
+import com.example.reactor.ProjectReactor.entity.Contact;
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.util.Assert;
+import reactor.core.Disposable;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Scheduler;
+import reactor.core.scheduler.Schedulers;
+import reactor.test.StepVerifier;
+import reactor.util.function.Tuple2;
+
+import java.util.Random;
+import java.util.stream.DoubleStream;
+
+@SpringBootTest
+public class MonoSample {
+
+
+    @Test
+    public void zip() {
+        Mono<String> mono = Mono.justOrEmpty("Ravi");
+        Mono<String> just = Mono.just("Pannala");
+        Mono<String> log = Mono.zip(mono, just, (a, b) -> a + "" + b).log();
+        StepVerifier.create(log).expectSubscription().expectNext("RaviPannala").expectComplete().verify();
+    }
+
+    public void block() {
+        String str = Mono.just("Ravi").block();
+    }
+
+    @Test
+    public void createMono() {
+        Mono<String> mono = Mono.just("Ravi");
+        mono.subscribe(a -> System.out.println("Mono with Just--->" + a));
+        Mono<Object> error = Mono.error(new Throwable());
+        error.subscribe(a -> System.out.println("Mono with Error--->" + a));
+        Mono<Object> empty = Mono.empty();
+        empty.subscribe(a -> System.out.println("Mono with empty--->" + a));
+        Mono<Integer> from = Mono.from(Flux.range(1, 10));
+        from.subscribe(s -> System.out.println("Mono with from --->" + s));
+        Random rd = new Random();
+        Mono<Double> doubleMono = Mono.fromSupplier(rd::nextDouble);
+        doubleMono.subscribe(s -> System.out.println("From Supplier-->" + s));
+        Mono<String> hello = Mono.fromCallable(() -> "Hello");
+        hello.subscribe(a -> System.out.println("From Callable --->" + a));
+    }
+
+    @Test
+    public void map() {
+        Mono<Contact> mono = Mono.just(new Contact("1", "Ravi", "Ravi@gmail.com", "3423523"));
+        Mono<String> stringMono = mono.map(c -> {
+            c.setName(null);
+            return c;
+        }).map(c -> c.getName()).onErrorReturn("Error Occured");
+        stringMono.subscribe(a -> System.out.println(a));
+    }
+
+    @Test
+    public void zipWith() {
+        Mono<String> ravinder = Mono.just("Ravinder");
+        Mono<Integer> just = Mono.just(1);
+        Mono<String> map = ravinder.zipWith(just).map(t -> {
+            return t.getT1() + t.getT2();
+        });
+        map.subscribe(s->System.out.println("zip With---->"+s));
+    }
+
+    @Test
+    public void filter(){
+        Mono<String> str1 = Mono.just("Ravi");
+        Mono<String> str2= Mono.just("Pannala");
+        Mono<String> map = str1.zipWith(str2).map(tule2 -> {
+            return tule2.getT2() + tule2.getT1();
+        });
+        Mono<String> stringMono = map.filter(str -> str.contains("Ravi")).switchIfEmpty(Mono.just("Error Occured"));
+        stringMono.subscribe(s->System.out.println("filter Mono--->"+s));
+    }
+
+    private <T> T identityWithThreadLogging(T el, String operation) {
+        System.out.println(operation + " -- " + el + " -- " +
+                Thread.currentThread().getName());
+        return el;
+    }
+    @Test
+    public void flatMapWithoutChangingScheduler() {
+        Flux.range(1,4)
+                .map(n->identityWithThreadLogging(n,"map1"))
+                .subscribeOn(Schedulers.boundedElastic())
+                .flatMap(f->Mono.just(f).map(n->identityWithThreadLogging(n,"mono")))
+                .subscribe(n-> {
+                    identityWithThreadLogging(n,"subscribe");
+                    System.out.println(n);
+                });
+    }
+
+    @Test
+    public void combiningParallelAndSequentialFlux() {
+        Flux.range(1, 4).
+                subscribeOn(Schedulers.parallel()).
+                map(n -> identityWithThreadLogging(n, "map1"))
+                .parallel()
+                .runOn(Schedulers.boundedElastic())
+                .map(n  -> identityWithThreadLogging(n, "parallelFlux"))
+                .sequential()
+                .map(n -> identityWithThreadLogging(n, "map2")).
+                subscribe(n -> identityWithThreadLogging(n, "subscribe"));
+    }
+
+}

src/test/java/com/example/reactor/ProjectReactor/ProjectReactorApplicationTests.java

+package com.example.reactor.ProjectReactor;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import reactor.core.publisher.Flux;
+
+@SpringBootTest
+class ProjectReactorApplicationTests {
+
+
+
+}

src/test/java/com/example/reactor/ProjectReactor/ResourceHandlers.java

+package com.example.reactor.ProjectReactor;
+
+import java.io.BufferedWriter;
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+
+public class ResourceHandlers {
+
+    private void close(Closeable closeable){
+        try {
+            closeable.close();
+            System.out.println("Closed the resource");
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    private void write(BufferedWriter bw, String string){
+        try {
+            bw.write(string);
+            bw.newLine();
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+}

src/test/java/com/example/reactor/ProjectReactor/SampleSubscriber.java

+package com.example.reactor.ProjectReactor;
+
+import org.reactivestreams.Subscription;
+import reactor.core.publisher.BaseSubscriber;
+
+public class SampleSubscriber<I extends Number> extends BaseSubscriber<Integer> {
+
+    protected void hookOnSubscribe(Subscription subscription) {
+        System.out.println("Hook on Subscribe");
+        request(1);
+    }
+
+    protected void hookOnNext(Integer value) {
+        System.out.println("Hook on Next");
+        request(1);
+    }
+}