bad java doing bad things

.devcontainer/devcontainer.json

@@ -0,0 +1,30 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/java
+{
+	"name": "Java",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	"image": "mcr.microsoft.com/devcontainers/java:1-21-bullseye",
+
+	"features": {
+		"ghcr.io/devcontainers/features/java:1": {
+			"version": "none",
+			"installMaven": "false",
+			"installGradle": "true"
+		},
+		"ghcr.io/devcontainers/features/docker-in-docker:2": {}
+	},
+	"mounts": [
+    "source=${localEnv:HOME}${localEnv:USERPROFILE},target=/host-home-folder,type=bind,consistency=cached",
+]
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// "forwardPorts": [],
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	// "postCreateCommand": "java -version",
+
+	// Configure tool-specific properties.
+	// "customizations": {},
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}

build.gradle

@@ -0,0 +1,26 @@
+plugins {
+    id 'org.springframework.boot' version '3.0.4'
+    id 'io.spring.dependency-management' version '1.1.0'
+    id 'java'
+}
+
+group = 'com.example.kafkaapp'
+version = '0.0.1-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation 'org.springframework.kafka:spring-kafka'
+    testImplementation('org.springframework.boot:spring-boot-starter-test') {
+        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
+    }
+}
+
+tasks.named('bootRun') {
+    doFirst {
+        systemProperty 'spring.profiles.active', 'dev' // Set active profile if needed
+    }
+}

build/resolvedMainClassName

@@ -0,0 +1 @@
+com.example.kafkaapp.KafkaApp

build/resources/main/application.yaml

@@ -0,0 +1,20 @@
+spring:
+  kafka:
+    bootstrap-servers: localhost:9093
+    consumer:
+      group-id: kafka-spring-app-group
+    security:
+      protocol: SSL
+    ssl:
+      trust-store-location: file:/workspaces/java-2/kafka.pfx 
+      trust-store-password: 
+      trust-store-type: pkcs12
+      key-store-location: file:/workspaces/java-2/kafka.pfx
+      key-store-password: 
+      key-store-type: pkcs12
+      key-password: 
+    properties:
+      "ssl-endpoint-identification-algorithm": ""
+    producer:
+      key-serializer: org.apache.kafka.common.serialization.StringSerializer
+      value-serializer: org.apache.kafka.common.serialization.StringSerializer

build/tmp/bootJar/MANIFEST.MF

@@ -0,0 +1,12 @@
+Manifest-Version: 1.0
+Main-Class: org.springframework.boot.loader.JarLauncher
+Start-Class: com.example.kafkaapp.KafkaApp
+Spring-Boot-Version: 3.0.4
+Spring-Boot-Classes: BOOT-INF/classes/
+Spring-Boot-Lib: BOOT-INF/lib/
+Spring-Boot-Classpath-Index: BOOT-INF/classpath.idx
+Spring-Boot-Layers-Index: BOOT-INF/layers.idx
+Build-Jdk-Spec: 21
+Implementation-Title: java-2
+Implementation-Version: 0.0.1-SNAPSHOT
+

build/tmp/jar/MANIFEST.MF

@@ -0,0 +1,2 @@
+Manifest-Version: 1.0
+

docker-compose.yaml

@@ -0,0 +1,37 @@
+version: '3'
+
+services:
+  zookeeper:
+    image: confluentinc/cp-zookeeper:7.9.0
+    container_name: zookeeper
+    environment:
+      ZOOKEEPER_CLIENT_PORT: 2181
+      ZOOKEEPER_TICK_TIME: 2000
+    ports:
+      - "2181:2181"
+
+  kafka:
+    image: confluentinc/cp-kafka:7.9.0
+    container_name: kafka
+    volumes:
+      - /workspaces/java-2/creds:/etc/kafka/secrets/
+    depends_on:
+      - zookeeper
+    environment:
+      KAFKA_BROKER_ID: 1
+      KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'
+      KAFKA_ADVERTISED_LISTENERS: 'PLAINTEXT://kafka:9092,SSL://localhost:9093'
+      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: 'PLAINTEXT:PLAINTEXT,SSL:SSL'
+      KAFKA_INTER_BROKER_LISTENER_NAME: PLAINTEXT
+      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
+      KAFKA_SSL_KEYSTORE_FILENAME: kafka.pfx
+      KAFKA_SSL_KEYSTORE_TYPE: PKCS12
+      KAFKA_SSL_CLIENT_AUTH: required
+      KAFKA_SSL_KEYSTORE_CREDENTIALS: empty
+      KAFKA_SSL_KEY_CREDENTIALS: empty
+      KAFKA_SSL_TRUSTSTORE_FILENAME: kafka.pfx
+      KAFKA_SSL_TRUSTSTORE_CREDENTIALS: empty
+      KAFKA_SSL_TRUSTSTORE_TYPE: PKCS12
+    ports:
+      - "9092:9092"
+      - "9093:9093"

dumb.crt

@@ -0,0 +1,19 @@
+-----BEGIN CERTIFICATE-----
+MIIDCTCCAfECFFGG94CeZ54LSnygfaCx3x+vJz7zMA0GCSqGSIb3DQEBCwUAMEEx
+CzAJBgNVBAYTAlVTMQswCQYDVQQIDAJPSDEPMA0GA1UECgwGd2FnbmVyMRQwEgYD
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+TYXPkvj/UGrRb1EJTg==
+-----END CERTIFICATE-----

dumb.csr

@@ -0,0 +1,16 @@
+-----BEGIN CERTIFICATE REQUEST-----
+MIIChjCCAW4CAQAwQTELMAkGA1UEBhMCVVMxCzAJBgNVBAgMAk9IMQ8wDQYDVQQK
+DAZ3YWduZXIxFDASBgNVBAMMC2R1bWIuaW5ob21lMIIBIjANBgkqhkiG9w0BAQEF
+AAOCAQ8AMIIBCgKCAQEA2C60hs9SJ4YUhIKTsqCG8L+cdteEHbdciumMoa/jSikD
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+XGhB18ed75BH5TSSgQETFIxvK5xJu1/e3RA=
+-----END CERTIFICATE REQUEST-----

dumb.key

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----
+MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQDYLrSGz1InhhSE
+gpOyoIbwv5x214Qdt1yK6Yyhr+NKKQO0xILkpNYEp8k8nZtx6KBCI1yzBOfT3qyW
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+Jaj+xs7C37PIQDTeuoUKCaI=
+-----END PRIVATE KEY-----

kafka-cert.crt

@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----
+MIIDOTCCAiECFE2uzPsjMIajh6lguqCd81S/8fb3MA0GCSqGSIb3DQEBCwUAMFkx
+CzAJBgNVBAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEwHwYDVQQKDBhJbnRl
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+9YPEnHnyvMfid/NiuA==
+-----END CERTIFICATE-----

kafka-private.key

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----
+MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQDHFM32yIXWyYkQ
+rd4WBry39aaU2z7HMwmLnj1y+nMJE0xtiMkZ8fS3UN8QZdx5PNFUMM3z0jI38mB1
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+dl2ZiVcbAgMBAAECggEAPIapu+7pKg0p2+VQkRfJRpCr7bPemUd+DnG0swFL+iVg
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+8kGpfsGw26qSkogbfJ7uz7c=
+-----END PRIVATE KEY-----

kafka.csr

@@ -0,0 +1,17 @@
+-----BEGIN CERTIFICATE REQUEST-----
+MIICnjCCAYYCAQAwWTELMAkGA1UEBhMCQVUxEzARBgNVBAgMClNvbWUtU3RhdGUx
+ITAfBgNVBAoMGEludGVybmV0IFdpZGdpdHMgUHR5IEx0ZDESMBAGA1UEAwwJbG9j
+YWxob3N0MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxxTN9siF1smJ
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+cD1e1WxOJFsom27hA9vwPJnLwTT61uB4nOjJxs4IZYnfKMkbX7BRUnyARg6+kEM6
+BHY=
+-----END CERTIFICATE REQUEST-----

src/main/java/com/example/kafkaapp/KafkaApp.java

@@ -0,0 +1,19 @@
+package com.example.kafkaapp;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ApplicationContext;
+import com.example.kafkaapp.service.ProducerService;
+
+@SpringBootApplication
+public class KafkaApp {
+    public static void main(String[] args) throws InterruptedException{
+        //SpringApplication.run(KafkaApp.class, args);
+        ApplicationContext context = SpringApplication.run(KafkaApp.class, args);
+        ProducerService producerService = context.getBean(ProducerService.class);
+        System.out.println("Waiting 10 seconds before sending the message...");
+        Thread.sleep(10_000);
+        System.out.println("ok, sending");
+        producerService.sendMessage("test-topic-0", "Hello from main()!");
+    }
+}

src/main/java/com/example/kafkaapp/service/KafkaConsumer.java

@@ -0,0 +1,15 @@
+package com.example.kafkaapp.service;
+
+import org.apache.kafka.clients.consumer.ConsumerRecord;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.kafka.annotation.KafkaListener;
+import org.springframework.stereotype.Service;
+
+@Service
+public class KafkaConsumer {
+
+    @KafkaListener(topics = "test-topic-0", groupId = "group_id")
+    public void listen(ConsumerRecord<String, String> record) {
+        System.out.println("Received message: " + record.value());
+    }
+}

src/main/java/com/example/kafkaapp/service/ProducerService.java

@@ -0,0 +1,59 @@
+package com.example.kafkaapp.service;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.stereotype.Service;
+import org.springframework.kafka.core.ProducerFactory;
+import org.apache.kafka.clients.producer.ProducerConfig;
+import org.apache.kafka.common.config.SslConfigs;
+import org.apache.kafka.common.serialization.StringSerializer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.kafka.core.DefaultKafkaProducerFactory;
+import org.springframework.kafka.core.KafkaTemplate;
+import org.springframework.kafka.core.ProducerFactory;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@Service
+public class ProducerService {
+
+    @Autowired
+    private KafkaTemplate<String, String> kafkaTemplate;
+
+    public void sendMessage(String topic, String message) {
+        kafkaTemplate.send(topic, message);
+    }
+
+}
+
+@Configuration
+class KafkaProducerConfig {
+
+    @Bean
+    public ProducerFactory<String, String> producerFactory() {
+        Map<String, Object> props = new HashMap<>();
+        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9093");
+        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
+        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
+        props.put("security.protocol", "SSL");
+        props.put(SslConfigs.SSL_TRUSTSTORE_LOCATION_CONFIG, "/workspaces/java-2/kafka.pfx");
+        props.put(SslConfigs.SSL_TRUSTSTORE_PASSWORD_CONFIG, "");
+        props.put(SslConfigs.SSL_KEYSTORE_LOCATION_CONFIG, "/workspaces/java-2/kafka.pfx");
+        props.put(SslConfigs.SSL_KEYSTORE_PASSWORD_CONFIG, "");
+        props.put(SslConfigs.SSL_KEYSTORE_TYPE_CONFIG, "PKCS12");
+        props.put(SslConfigs.SSL_KEY_PASSWORD_CONFIG, "");
+
+        // ✅ Disable hostname verification (the "single extra property")
+        props.put(SslConfigs.SSL_ENDPOINT_IDENTIFICATION_ALGORITHM_CONFIG, "");
+        props.put("ssl.endpoint.identification.algorithm", "");
+
+        return new DefaultKafkaProducerFactory<>(props);
+    }
+
+    @Bean
+    public KafkaTemplate<String, String> kafkaTemplate() {
+        return new KafkaTemplate<>(producerFactory());
+    }
+}

src/main/resources/application.yaml

@@ -0,0 +1,20 @@
+spring:
+  kafka:
+    bootstrap-servers: localhost:9093
+    consumer:
+      group-id: kafka-spring-app-group
+    security:
+      protocol: SSL
+    ssl:
+      trust-store-location: file:/workspaces/java-2/kafka.pfx 
+      trust-store-password: 
+      trust-store-type: pkcs12
+      key-store-location: file:/workspaces/java-2/kafka.pfx
+      key-store-password: 
+      key-store-type: pkcs12
+      key-password: 
+    properties:
+      "ssl-endpoint-identification-algorithm": ""
+    producer:
+      key-serializer: org.apache.kafka.common.serialization.StringSerializer
+      value-serializer: org.apache.kafka.common.serialization.StringSerializer