Added kafka with cloud stream (producer and consumer)

.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/MavenWrapperDownloader.java

+/*
+ * Copyright 2007-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

.mvn/wrapper/maven-wrapper.properties

+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.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 "%HOME%\mavenrc_pre.bat" call "%HOME%\mavenrc_pre.bat"
+if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\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/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+
+FOR /F "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%/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.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 "%HOME%\mavenrc_post.bat" call "%HOME%\mavenrc_post.bat"
+if exist "%HOME%\mavenrc_post.cmd" call "%HOME%\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%
+
+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>2.3.3.RELEASE</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+    <groupId>com.example</groupId>
+    <artifactId>Cloud-Stream-Kafka-Example</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>Cloud-Stream-Kafka-Example</name>
+    <description>Demo project for Spring Boot</description>
+
+    <properties>
+        <java.version>1.8</java.version>
+        <spring-cloud.version>Hoxton.SR8</spring-cloud.version>
+
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-stream</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-stream-binder-kafka</artifactId>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+            <version>2.3.0.RELEASE</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-stream-schema</artifactId>
+            <version>2.0.0.RELEASE</version>
+        </dependency>
+        <dependency>
+            <groupId>io.confluent</groupId>
+            <artifactId>kafka-avro-serializer</artifactId>
+            <version>5.4.0</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.avro</groupId>
+            <artifactId>avro-compiler</artifactId>
+            <version>1.9.2</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.avro</groupId>
+            <artifactId>avro-maven-plugin</artifactId>
+            <version>1.9.2</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.kafka</groupId>
+            <artifactId>spring-kafka</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.junit.vintage</groupId>
+                    <artifactId>junit-vintage-engine</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-stream-test-support</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.kafka</groupId>
+            <artifactId>spring-kafka-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-dependencies</artifactId>
+                <version>${spring-cloud.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.avro</groupId>
+                <artifactId>avro-maven-plugin</artifactId>
+                <version>1.8.2</version>
+                <executions>
+                    <execution>
+                        <id>schemas</id>
+                        <phase>generate-sources</phase>
+                        <goals>
+                            <goal>schema</goal>
+                            <goal>protocol</goal>
+                            <goal>idl-protocol</goal>
+                        </goals>
+                        <configuration>
+                            <sourceDirectory>${project.basedir}/src/main/resources/</sourceDirectory>
+                            <outputDirectory>${project.basedir}/src/main/java/</outputDirectory>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <repositories>
+        <repository>
+            <id>confluent</id>
+            <url>https://packages.confluent.io/maven/</url>
+        </repository>
+    </repositories>
+
+
+</project>

src/main/java/avro/ProductKey.java

+/**
+ * Autogenerated by Avro
+ *
+ * DO NOT EDIT DIRECTLY
+ */
+package avro;
+
+import org.apache.avro.specific.SpecificData;
+import org.apache.avro.message.BinaryMessageEncoder;
+import org.apache.avro.message.BinaryMessageDecoder;
+import org.apache.avro.message.SchemaStore;
+
+@SuppressWarnings("all")
+@org.apache.avro.specific.AvroGenerated
+public class ProductKey extends org.apache.avro.specific.SpecificRecordBase implements org.apache.avro.specific.SpecificRecord {
+  private static final long serialVersionUID = 3937452775853075512L;
+  public static final org.apache.avro.Schema SCHEMA$ = new org.apache.avro.Schema.Parser().parse("{\"type\":\"record\",\"name\":\"ProductKey\",\"namespace\":\"avro\",\"fields\":[{\"name\":\"id\",\"type\":[\"long\",\"null\"]},{\"name\":\"categoryId\",\"type\":[\"long\",\"null\"],\"doc\":\"category Id of the product \"}]}");
+  public static org.apache.avro.Schema getClassSchema() { return SCHEMA$; }
+
+  private static SpecificData MODEL$ = new SpecificData();
+
+  private static final BinaryMessageEncoder<ProductKey> ENCODER =
+      new BinaryMessageEncoder<ProductKey>(MODEL$, SCHEMA$);
+
+  private static final BinaryMessageDecoder<ProductKey> DECODER =
+      new BinaryMessageDecoder<ProductKey>(MODEL$, SCHEMA$);
+
+  /**
+   * Return the BinaryMessageDecoder instance used by this class.
+   */
+  public static BinaryMessageDecoder<ProductKey> getDecoder() {
+    return DECODER;
+  }
+
+  /**
+   * Create a new BinaryMessageDecoder instance for this class that uses the specified {@link SchemaStore}.
+   * @param resolver a {@link SchemaStore} used to find schemas by fingerprint
+   */
+  public static BinaryMessageDecoder<ProductKey> createDecoder(SchemaStore resolver) {
+    return new BinaryMessageDecoder<ProductKey>(MODEL$, SCHEMA$, resolver);
+  }
+
+  /** Serializes this ProductKey to a ByteBuffer. */
+  public java.nio.ByteBuffer toByteBuffer() throws java.io.IOException {
+    return ENCODER.encode(this);
+  }
+
+  /** Deserializes a ProductKey from a ByteBuffer. */
+  public static ProductKey fromByteBuffer(
+      java.nio.ByteBuffer b) throws java.io.IOException {
+    return DECODER.decode(b);
+  }
+
+  @Deprecated public java.lang.Long id;
+  /** category Id of the product  */
+  @Deprecated public java.lang.Long categoryId;
+
+  /**
+   * Default constructor.  Note that this does not initialize fields
+   * to their default values from the schema.  If that is desired then
+   * one should use <code>newBuilder()</code>.
+   */
+  public ProductKey() {}
+
+  /**
+   * All-args constructor.
+   * @param id The new value for id
+   * @param categoryId category Id of the product 
+   */
+  public ProductKey(java.lang.Long id, java.lang.Long categoryId) {
+    this.id = id;
+    this.categoryId = categoryId;
+  }
+
+  public org.apache.avro.Schema getSchema() { return SCHEMA$; }
+  // Used by DatumWriter.  Applications should not call.
+  public java.lang.Object get(int field$) {
+    switch (field$) {
+    case 0: return id;
+    case 1: return categoryId;
+    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
+    }
+  }
+
+  // Used by DatumReader.  Applications should not call.
+  @SuppressWarnings(value="unchecked")
+  public void put(int field$, java.lang.Object value$) {
+    switch (field$) {
+    case 0: id = (java.lang.Long)value$; break;
+    case 1: categoryId = (java.lang.Long)value$; break;
+    default: throw new org.apache.avro.AvroRuntimeException("Bad index");
+    }
+  }
+
+  /**
+   * Gets the value of the 'id' field.
+   * @return The value of the 'id' field.
+   */
+  public java.lang.Long getId() {
+    return id;
+  }
+
+  /**
+   * Sets the value of the 'id' field.
+   * @param value the value to set.
+   */
+  public void setId(java.lang.Long value) {
+    this.id = value;
+  }
+
+  /**
+   * Gets the value of the 'categoryId' field.
+   * @return category Id of the product 
+   */
+  public java.lang.Long getCategoryId() {
+    return categoryId;
+  }
+
+  /**
+   * Sets the value of the 'categoryId' field.
+   * category Id of the product 
+   * @param value the value to set.
+   */
+  public void setCategoryId(java.lang.Long value) {
+    this.categoryId = value;
+  }
+
+  /**
+   * Creates a new ProductKey RecordBuilder.
+   * @return A new ProductKey RecordBuilder
+   */
+  public static avro.ProductKey.Builder newBuilder() {
+    return new avro.ProductKey.Builder();
+  }
+
+  /**
+   * Creates a new ProductKey RecordBuilder by copying an existing Builder.
+   * @param other The existing builder to copy.
+   * @return A new ProductKey RecordBuilder
+   */
+  public static avro.ProductKey.Builder newBuilder(avro.ProductKey.Builder other) {
+    return new avro.ProductKey.Builder(other);
+  }
+
+  /**
+   * Creates a new ProductKey RecordBuilder by copying an existing ProductKey instance.
+   * @param other The existing instance to copy.
+   * @return A new ProductKey RecordBuilder
+   */
+  public static avro.ProductKey.Builder newBuilder(avro.ProductKey other) {
+    return new avro.ProductKey.Builder(other);
+  }
+
+  /**
+   * RecordBuilder for ProductKey instances.
+   */
+  public static class Builder extends org.apache.avro.specific.SpecificRecordBuilderBase<ProductKey>
+    implements org.apache.avro.data.RecordBuilder<ProductKey> {
+
+    private java.lang.Long id;
+    /** category Id of the product  */
+    private java.lang.Long categoryId;
+
+    /** Creates a new Builder */
+    private Builder() {
+      super(SCHEMA$);
+    }
+
+    /**
+     * Creates a Builder by copying an existing Builder.
+     * @param other The existing Builder to copy.
+     */
+    private Builder(avro.ProductKey.Builder other) {
+      super(other);
+      if (isValidValue(fields()[0], other.id)) {
+        this.id = data().deepCopy(fields()[0].schema(), other.id);
+        fieldSetFlags()[0] = true;
+      }
+      if (isValidValue(fields()[1], other.categoryId)) {
+        this.categoryId = data().deepCopy(fields()[1].schema(), other.categoryId);
+        fieldSetFlags()[1] = true;
+      }
+    }
+
+    /**
+     * Creates a Builder by copying an existing ProductKey instance
+     * @param other The existing instance to copy.
+     */
+    private Builder(avro.ProductKey other) {
+            super(SCHEMA$);
+      if (isValidValue(fields()[0], other.id)) {
+        this.id = data().deepCopy(fields()[0].schema(), other.id);
+        fieldSetFlags()[0] = true;
+      }
+      if (isValidValue(fields()[1], other.categoryId)) {
+        this.categoryId = data().deepCopy(fields()[1].schema(), other.categoryId);
+        fieldSetFlags()[1] = true;
+      }
+    }
+
+    /**
+      * Gets the value of the 'id' field.
+      * @return The value.
+      */
+    public java.lang.Long getId() {
+      return id;
+    }
+
+    /**
+      * Sets the value of the 'id' field.
+      * @param value The value of 'id'.
+      * @return This builder.
+      */
+    public avro.ProductKey.Builder setId(java.lang.Long value) {
+      validate(fields()[0], value);
+      this.id = value;
+      fieldSetFlags()[0] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'id' field has been set.
+      * @return True if the 'id' field has been set, false otherwise.
+      */
+    public boolean hasId() {
+      return fieldSetFlags()[0];
+    }
+
+
+    /**
+      * Clears the value of the 'id' field.
+      * @return This builder.
+      */
+    public avro.ProductKey.Builder clearId() {
+      id = null;
+      fieldSetFlags()[0] = false;
+      return this;
+    }
+
+    /**
+      * Gets the value of the 'categoryId' field.
+      * category Id of the product 
+      * @return The value.
+      */
+    public java.lang.Long getCategoryId() {
+      return categoryId;
+    }
+
+    /**
+      * Sets the value of the 'categoryId' field.
+      * category Id of the product 
+      * @param value The value of 'categoryId'.
+      * @return This builder.
+      */
+    public avro.ProductKey.Builder setCategoryId(java.lang.Long value) {
+      validate(fields()[1], value);
+      this.categoryId = value;
+      fieldSetFlags()[1] = true;
+      return this;
+    }
+
+    /**
+      * Checks whether the 'categoryId' field has been set.
+      * category Id of the product 
+      * @return True if the 'categoryId' field has been set, false otherwise.
+      */
+    public boolean hasCategoryId() {
+      return fieldSetFlags()[1];
+    }
+
+
+    /**
+      * Clears the value of the 'categoryId' field.
+      * category Id of the product 
+      * @return This builder.
+      */
+    public avro.ProductKey.Builder clearCategoryId() {
+      categoryId = null;
+      fieldSetFlags()[1] = false;
+      return this;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public ProductKey build() {
+      try {
+        ProductKey record = new ProductKey();
+        record.id = fieldSetFlags()[0] ? this.id : (java.lang.Long) defaultValue(fields()[0]);
+        record.categoryId = fieldSetFlags()[1] ? this.categoryId : (java.lang.Long) defaultValue(fields()[1]);
+        return record;
+      } catch (java.lang.Exception e) {
+        throw new org.apache.avro.AvroRuntimeException(e);
+      }
+    }
+  }
+
+  @SuppressWarnings("unchecked")
+  private static final org.apache.avro.io.DatumWriter<ProductKey>
+    WRITER$ = (org.apache.avro.io.DatumWriter<ProductKey>)MODEL$.createDatumWriter(SCHEMA$);
+
+  @Override public void writeExternal(java.io.ObjectOutput out)
+    throws java.io.IOException {
+    WRITER$.write(this, SpecificData.getEncoder(out));
+  }
+
+  @SuppressWarnings("unchecked")
+  private static final org.apache.avro.io.DatumReader<ProductKey>
+    READER$ = (org.apache.avro.io.DatumReader<ProductKey>)MODEL$.createDatumReader(SCHEMA$);
+
+  @Override public void readExternal(java.io.ObjectInput in)
+    throws java.io.IOException {
+    READER$.read(this, SpecificData.getDecoder(in));
+  }
+
+}

src/main/java/com/example/CloudStreamKafkaExampleApplication.java

+package com.example;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.stream.annotation.EnableBinding;
+import org.springframework.cloud.stream.messaging.Processor;
+import org.springframework.cloud.stream.schema.client.EnableSchemaRegistryClient;
+
+
+@SpringBootApplication
+@EnableBinding(Processor.class)
+@EnableSchemaRegistryClient
+public class CloudStreamKafkaExampleApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(CloudStreamKafkaExampleApplication.class, args);
+	}
+
+}

src/main/java/com/example/config/SchemaRegistryConfig.java

+package com.example.config;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.cloud.stream.schema.client.ConfluentSchemaRegistryClient;
+import org.springframework.cloud.stream.schema.client.SchemaRegistryClient;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class SchemaRegistryConfig {
+
+    @Bean
+    public SchemaRegistryClient schemaRegistryClient(@Value("${spring.cloud.stream.kafka.binder.producer-properties.schema.registry.url}") String endPoint) {
+        ConfluentSchemaRegistryClient client = new ConfluentSchemaRegistryClient();
+        client.setEndpoint(endPoint);
+        return client;
+    }
+}

src/main/java/com/example/consumer/Consumer.java

+package com.example.consumer;
+
+import avro.Product;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.cloud.stream.annotation.StreamListener;
+import org.springframework.cloud.stream.messaging.Processor;
+import org.springframework.stereotype.Service;
+
+@Service
+public class Consumer {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(Consumer.class);
+
+    @StreamListener(Processor.INPUT)
+    public void consumeProductDetails(Product productDetails) {
+        LOGGER.info("Consuming the  product details: {}", productDetails);
+    }
+
+}
\ No newline at end of file

src/main/java/com/example/controller/Controller.java

+package com.example.controller;
+
+import avro.Product;
+import com.example.consumer.Consumer;
+import com.example.producer.Producer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class Controller {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(Controller.class);
+
+    @Autowired
+    private Producer producer;
+
+    @PostMapping("/publish")
+    public String producerAvroMessage(@RequestBody Product product) {
+        LOGGER.info("Started publishing product data{}",product.toString());
+        producer.produceProductDetails(product);
+        return "Sent product details to consumer";
+    }
+
+}
\ No newline at end of file

src/main/java/com/example/producer/Producer.java

+package com.example.producer;
+
+import avro.Product;
+import avro.ProductKey;
+import com.example.controller.Controller;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.cloud.stream.messaging.Processor;
+import org.springframework.kafka.support.KafkaHeaders;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.stereotype.Service;
+
+@Service
+public class Producer {
+    private static final Logger LOGGER = LoggerFactory.getLogger(Producer.class);
+
+    @Autowired
+    private Processor processor;
+
+    public void produceProductDetails(Product product) {
+
+        // creating partition key for kafka topic
+        ProductKey productKey = new ProductKey();
+        productKey.setId(product.getId());
+        productKey.setCategoryId(product.getCategoryId());
+        Message<Product> message = MessageBuilder.withPayload(product)
+                .setHeader(KafkaHeaders.MESSAGE_KEY, productKey)
+                .build();
+
+        LOGGER.info("Sending Product data with key {} and value as {}",productKey.toString(),product.toString());
+
+        processor.output().send(message);
+    }
+
+}
\ No newline at end of file

src/main/resources/application.yml

+spring:
+  cloud:
+    stream:
+      default:
+        producer:
+          useNativeEncoding: true
+        consumer:
+          useNativeEncoding: true
+      bindings:
+        input:
+          destination: product-data
+          content-type: application/*+avro
+          group: group-1
+          concurrency: 3
+        output:
+          destination: product-data
+          content-type: application/*+avro
+      kafka:
+        binder:
+          producer-properties:
+            key.serializer: io.confluent.kafka.serializers.KafkaAvroSerializer
+            value.serializer: io.confluent.kafka.serializers.KafkaAvroSerializer
+            schema.registry.url: http://localhost:8081
+          consumer-properties:
+            key.deserializer: io.confluent.kafka.serializers.KafkaAvroDeserializer
+            value.deserializer: io.confluent.kafka.serializers.KafkaAvroDeserializer
+            schema.registry.url: http://localhost:8081
+            specific.avro.reader: true
\ No newline at end of file

src/main/resources/product-key-schema.avsc

+{
+	"type": "record",
+	"name": "ProductKey",
+	"namespace": "avro",
+	"fields": [
+	 {
+		"name": "id",
+		"type": ["long","null"]
+	},
+	{
+	    "name":"categoryId",
+	    "type": ["long", "null"],
+	    "doc": "category Id of the product "
+	}
+	 ]
+}
\ No newline at end of file

src/main/resources/product-value-schema.avsc

+{
+           "type":"record",
+           "namespace":"avro",
+           "name":"Product",
+           "doc":"This is Product Information",
+           "fields":[
+                    { "name":"id","type":["long","null"],"doc":"product ID."},
+                    { "name":"name","type": ["string", "null"],"doc": "Name of the product "},
+                    { "name":"category","type": ["string", "null"],"doc": "category of the product "},
+                    { "name":"categoryId","type": ["long", "null"],"doc": "category Id of the product "},
+                    { "name":"price","type": ["long", "null"],"doc": "price of the product "},
+                    { "name":"quantity","type": ["int", "null"],"doc": "quantity of the product "}
+                    ]
+           }

src/test/java/com/example/CloudStreamKafkaExampleApplicationTests.java

+package com.example;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class CloudStreamKafkaExampleApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}