added a Java example for creating an S3 Object Lambda

java/s3-object-lambda/.gitignore

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+.classpath.txt
+target
+.classpath
+.project
+.idea
+.settings
+.vscode
+*.iml
+
+# CDK asset staging directory
+.cdk.staging
+cdk.out
+

java/s3-object-lambda/README.md

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+# S3 Object Lambda
+
+<!--BEGIN STABILITY BANNER-->
+
+---
+![Stability: Stable](https://img.shields.io/badge/stability-Stable-success.svg?style=for-the-badge)
+> **This is a stable example. It should successfully build out of the box**
+>
+> This example is built on Construct Libraries marked "Stable" and does not have any infrastructure prerequisites to build.
+---
+
+<!--END STABILITY BANNER-->
+
+## Overview
+
+This is a Java CDK example to create a [S3 Object Lambda](https://docs.aws.amazon.com/AmazonS3/latest/userguide/transforming-objects.html).
+The main cloud infrastructure resources created with this example are:
+- an S3 Bucket;
+- a S3 Access Point;
+- an S3 Object Lambda Access Point;
+- a Lambda Function to process the GET object requests.
+
+Once this example is deployed, any object uploaded in the bucket created will be available through the S3 Object Lambda Access Point.
+When trying to access an object through the S3 Object Lambda Access Point, a metadata output generated by the lambda function will be returned.
+The object metadata output generated by the lambda is similar to the following:
+```json
+{
+  "metadata": {
+    "length": 1048576,
+    "md5": "b6d81b360a5672d80c27430f39153e2c",
+    "sha1": "3b71f43ff30f4b15b5cd85dd9e95ebc7e84eb5a3",
+    "sha256": "30e14955ebf1352266dc2ff8067e68104607e750abb9d3b36582b8af909fcb58"
+  }
+}
+```
+
+## Build
+
+**To build this example, you need to be in this example's [`infra`](infra) directory.** Then run the following:
+```bash
+  npm install -g aws-cdk
+  npm install
+  cdk synth
+```
+> [!NOTE]
+> In order to build this project you need [Docker](https://www.docker.com/) (and [Docker Desktop](https://www.docker.com/products/docker-desktop/) if you want to use a GUI) installed.
+> Moreover, the Docker daemon must be running while you execute the build or deploy commands.
+> Unless the Docker daemon is running the Maven build of the lambda function ([`S3ObjectLambdaTransformer`](lambda/src/main/java/com/myorg/S3ObjectLambdaTransformer.java)) will fail.
+> This is required because the CDK will build the code for the lambda function locally in a Docker container.
+> You should also create a **virtual file share** for the local `/tmp` directory (see [Synchronized file shares](https://docs.docker.com/desktop/synchronized-file-sharing/)).
+> This can be done from Docker Desktop (`Settings>Resources>File sharing`).
+
+> [!NOTE]
+> When you build this project for the first time, the required Docker image ([sam/build-java17](https://gallery.ecr.aws/sam/build-java17)) will be pulled from AWS ECR.
+> This will cause the first build to be slower.
+> That is unless the required container image is already present on the system.
+
+## Deploy
+
+To deploy this example, you need to be in this example's [`infra`](infra) directory and run `cdk deploy`.
+This will deploy / redeploy the Stack to AWS.
+After the CDK deployment is successful, the URL of the S3 Object Lambda Access Point (the output named `S3ObjectLambdaStack.s3ObjectLambdaAccessPointUrl`) will be available in the terminal console.
+At this point, this URL can be used for testing.
+Copy the URL and paste it in the address bar of a browser.
+This will take you to the access point in the AWS management console (you need to be authenticated for that).
+From here you can access an S3 object to get the corresponding metadata (you need to have objects in the bucket for that).
+
+## Useful commands
+
+ * `mvn package`     compile and run tests
+ * `cdk ls`          list all stacks in the app
+ * `cdk synth`       emits the synthesized CloudFormation template
+ * `cdk deploy`      deploy this stack to your default AWS account/region
+ * `cdk diff`        compare deployed stack with current state
+ * `cdk docs`        open CDK documentation

java/s3-object-lambda/infra/.gitignore

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+.classpath.txt
+target
+.classpath
+.project
+.idea
+.settings
+.vscode
+*.iml
+
+# CDK asset staging directory
+.cdk.staging
+cdk.out
+

java/s3-object-lambda/infra/cdk.json

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+{
+  "app": "mvn -e -q compile exec:java",
+  "watch": {
+    "include": [
+      "**"
+    ],
+    "exclude": [
+      "README.md",
+      "cdk*.json",
+      "target",
+      "pom.xml",
+      "src/test"
+    ]
+  },
+  "context": {
+    "@aws-cdk/aws-lambda:recognizeLayerVersion": true,
+    "@aws-cdk/core:checkSecretUsage": true,
+    "@aws-cdk/core:target-partitions": [
+      "aws",
+      "aws-cn"
+    ],
+    "@aws-cdk-containers/ecs-service-extensions:enableDefaultLogDriver": true,
+    "@aws-cdk/aws-ec2:uniqueImdsv2TemplateName": true,
+    "@aws-cdk/aws-ecs:arnFormatIncludesClusterName": true,
+    "@aws-cdk/aws-iam:minimizePolicies": true,
+    "@aws-cdk/core:validateSnapshotRemovalPolicy": true,
+    "@aws-cdk/aws-codepipeline:crossAccountKeyAliasStackSafeResourceName": true,
+    "@aws-cdk/aws-s3:createDefaultLoggingPolicy": true,
+    "@aws-cdk/aws-sns-subscriptions:restrictSqsDescryption": true,
+    "@aws-cdk/aws-apigateway:disableCloudWatchRole": true,
+    "@aws-cdk/core:enablePartitionLiterals": true,
+    "@aws-cdk/aws-events:eventsTargetQueueSameAccount": true,
+    "@aws-cdk/aws-ecs:disableExplicitDeploymentControllerForCircuitBreaker": true,
+    "@aws-cdk/aws-iam:importedRoleStackSafeDefaultPolicyName": true,
+    "@aws-cdk/aws-s3:serverAccessLogsUseBucketPolicy": true,
+    "@aws-cdk/aws-route53-patters:useCertificate": true,
+    "@aws-cdk/customresources:installLatestAwsSdkDefault": false,
+    "@aws-cdk/aws-rds:databaseProxyUniqueResourceName": true,
+    "@aws-cdk/aws-codedeploy:removeAlarmsFromDeploymentGroup": true,
+    "@aws-cdk/aws-apigateway:authorizerChangeDeploymentLogicalId": true,
+    "@aws-cdk/aws-ec2:launchTemplateDefaultUserData": true,
+    "@aws-cdk/aws-secretsmanager:useAttachedSecretResourcePolicyForSecretTargetAttachments": true,
+    "@aws-cdk/aws-redshift:columnId": true,
+    "@aws-cdk/aws-stepfunctions-tasks:enableEmrServicePolicyV2": true,
+    "@aws-cdk/aws-ec2:restrictDefaultSecurityGroup": true,
+    "@aws-cdk/aws-apigateway:requestValidatorUniqueId": true,
+    "@aws-cdk/aws-kms:aliasNameRef": true,
+    "@aws-cdk/aws-autoscaling:generateLaunchTemplateInsteadOfLaunchConfig": true,
+    "@aws-cdk/core:includePrefixInUniqueNameGeneration": true,
+    "@aws-cdk/aws-efs:denyAnonymousAccess": true,
+    "@aws-cdk/aws-opensearchservice:enableOpensearchMultiAzWithStandby": true,
+    "@aws-cdk/aws-lambda-nodejs:useLatestRuntimeVersion": true,
+    "@aws-cdk/aws-efs:mountTargetOrderInsensitiveLogicalId": true,
+    "@aws-cdk/aws-rds:auroraClusterChangeScopeOfInstanceParameterGroupWithEachParameters": true,
+    "@aws-cdk/aws-appsync:useArnForSourceApiAssociationIdentifier": true,
+    "@aws-cdk/aws-rds:preventRenderingDeprecatedCredentials": true,
+    "@aws-cdk/aws-codepipeline-actions:useNewDefaultBranchForCodeCommitSource": true,
+    "@aws-cdk/aws-cloudwatch-actions:changeLambdaPermissionLogicalIdForLambdaAction": true,
+    "@aws-cdk/aws-codepipeline:crossAccountKeysDefaultValueToFalse": true,
+    "@aws-cdk/aws-codepipeline:defaultPipelineTypeToV2": true,
+    "@aws-cdk/aws-kms:reduceCrossAccountRegionPolicyScope": true,
+    "@aws-cdk/aws-eks:nodegroupNameAttribute": true,
+    "@aws-cdk/aws-ec2:ebsDefaultGp3Volume": true,
+    "@aws-cdk/aws-ecs:removeDefaultDeploymentAlarm": true,
+    "@aws-cdk/custom-resources:logApiResponseDataPropertyTrueDefault": false,
+    "@aws-cdk/aws-s3:keepNotificationInImportedBucket": false,
+    "@aws-cdk/aws-ecs:reduceEc2FargateCloudWatchPermissions": true,
+    "@aws-cdk/aws-dynamodb:resourcePolicyPerReplica": true,
+    "@aws-cdk/aws-ec2:ec2SumTImeoutEnabled": true,
+    "@aws-cdk/aws-appsync:appSyncGraphQLAPIScopeLambdaPermission": true,
+    "@aws-cdk/aws-rds:setCorrectValueForDatabaseInstanceReadReplicaInstanceResourceId": true,
+    "@aws-cdk/core:cfnIncludeRejectComplexResourceUpdateCreatePolicyIntrinsics": true,
+    "@aws-cdk/aws-lambda-nodejs:sdkV3ExcludeSmithyPackages": true,
+    "@aws-cdk/aws-stepfunctions-tasks:fixRunEcsTaskPolicy": true
+  }
+}

java/s3-object-lambda/infra/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+         xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.myorg.s3-object-lambda</groupId>
+  <artifactId>infra</artifactId>
+  <name>infra</name>
+  <version>0.1</version>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.release>17</maven.compiler.release>
+    <java.version>17</java.version>
+    <cdk.version>2.171.1</cdk.version>
+    <constructs.version>[10.0.0,11.0.0)</constructs.version>
+    <junit.version>5.7.1</junit.version>
+    <lombok.version>1.18.34</lombok.version>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.11.0</version>
+        <configuration>
+          <source>${java.version}</source>
+          <target>${java.version}</target>
+          <release>${java.version}</release>
+        </configuration>
+      </plugin>
+
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <version>3.1.0</version>
+        <configuration>
+          <mainClass>com.myorg.S3ObjectLambdaApp</mainClass>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+
+  <dependencies>
+    <!-- AWS Cloud Development Kit -->
+    <dependency>
+      <groupId>software.amazon.awscdk</groupId>
+      <artifactId>aws-cdk-lib</artifactId>
+      <version>${cdk.version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>software.constructs</groupId>
+      <artifactId>constructs</artifactId>
+      <version>${constructs.version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>${junit.version}</version>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>${lombok.version}</version>
+      <scope>provided</scope>
+    </dependency>
+  </dependencies>
+</project>

java/s3-object-lambda/infra/src/main/java/com/myorg/S3ObjectLambdaApp.java

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+package com.myorg;
+
+import software.amazon.awscdk.App;
+import software.amazon.awscdk.StackProps;
+
+/**
+ * Main CDK application class that serves as the entry point for deploying the S3 Object Lambda infrastructure.
+ */
+public class S3ObjectLambdaApp extends App {
+
+  public static void main(final String... args) {
+    var app = new S3ObjectLambdaApp();
+    var stackProps = StackProps.builder().build();
+    app.createStack(stackProps);
+    app.synth();
+  }
+
+  /**
+   * Creates a new instance of the S3ObjectLambdaStack with the specified properties.
+   */
+  public S3ObjectLambdaStack createStack(StackProps stackProps) {
+    return new S3ObjectLambdaStack(this, "S3ObjectLambdaStack", stackProps);
+  }
+
+}
+