This page describes how to work with Lambda function handlers in Java, including options for project setup, naming conventions, and best practices. This page also includes an example of a Java Lambda function that takes in information about an order, produces a text file receipt, and puts this ...

Lambda supports the following Java runtimes. AWS provides the following libraries for Java functions. These libraries are available through Maven Central Repository ... (required) – Defines handler method interfaces and the context object that the runtime passes to the handler.

April 17, 2025 - AWSTemplateFormatVersion: '2010-09-09' Description: Lambda function deployment with Java 21 runtime Parameters: LambdaHandler: Type: String Description: The handler for the Lambda function S3BucketName: Type: String Description: The name of the S3 bucket containing the Lambda function JAR file S3Key: Type: String Description: The S3 key (file name) of the Lambda function JAR file Resources: BaeldungLambdaFunction: Type: AWS::Lambda::Function Properties: FunctionName: baeldung-lambda-function Handler: !Ref LambdaHandler Role: !GetAtt LambdaExecutionRole.Arn Code: S3Bucket: !Ref S3BucketName S3K

July 23, 2025 - Step 9: To invoke the lambda function we have to give the handler name in lambda console as we have seen in “Let’s create AWS Lambda from AWS Console and upload the build.”. We have to give “org.springframework.cloud.function.adapter.aws.FunctionInvoker ” class name along with handleRequest so any event occurs in lambda it will call this class name in the execution environment. We have successfully built the jar file for aws lambda using Spring cloud functions. We can upload the build file and execute the lambda as we have seen above. We have learnt about what is AWS Lambda, what are the use cases and where we can use AWS Lambda functions in application. We have successfully built the project in Java using aws lambda core library where we have to create a class which implement RequestHandler core interface.

* Lambda request handlers implement AWS Lambda Function application logic using plain old java objects

December 16, 2020 - The related AWS docs are here. I found it really confusing so I’ll try to summarize. First, your class should implement one of these two interfaces: [Option 1] com.amazonaws.services.lambda.runtime.RequestHandler · [Option 2] com.amazonaws.services.lambda.runtime.RequestStreamHandler · This is the simplest way to write your function. With this option, your handler class should implement RequestHandler and your handler method should have two parameters: the event and the context .

September 17, 2024 - The aws-lambda-java-core library defines two interfaces for handler methods.

When Lambda runs your function, it passes a context object to the handler . This object provides methods and properties that provide information about the invocation, function, and execution environment.

February 6, 2024 - We know that writing unit and integration tests for Lambda can be a challenge, especially in Java, and today we are happy to announce the release of aws-lambda-java-tests, an opinionated library that simplifies writing tests. The handler is the entry point of your Lambda function: This is the ...

October 26, 2020 - The map object will have all the information coming from the event (from the trigger, e.g. API Gateway, as a JSON formatted string), and the context is the information about the invocation (AWS request ID, lambda function version, lambda function ARN, execution environment details, and Cognito identity information). If you need to take advantage of the execution context for reuse (if the lambda function is on hold waiting for another usage), you can create some global variables (for example to create database connections, loggers, etc) public class Handler implements RequestHandler<Map<String,String>, String>{ private static final Logger logger = LoggerFactory.getLogger(Handler.class); @Override public String handleRequest(Map<String,String> event, Context context) { String response = new String("200 OK"); ...

October 27, 2022 - First, before you change your code, you’ll go the AWS Lambda Console and select Actions then Publish new version. Give it a name and go for it. Next, you’ll need to get the package that has the S3 classes. See, the Java handler function has to take the S3 Put type as the first parameter.

The GitHub repository for this guide provides sample applications that demonstrate the use of Java in AWS Lambda. Each sample application includes scripts for easy deployment and cleanup, an CloudFormation template, and supporting resources.

January 16, 2021 - AWS Lambda tries to re-use containers across invocations. Our handler class is held by the runtime as a singleton and the handleRequest method is invoked each time. We can re-use both the ResourceConfig and JerseyLambdaContainerHandler. Static variables are instantiated by the Java runtime as ...

January 12, 2022 - There is plenty of documentation on Java SDK version for 1 using the RequestHandler interface and the Context object but there is no documentation on the equivalent in Java SDK version 2.X. All the Java 2.X lambda documentation pertains to creating/registering/listing/deleting lambda functions in AWS but not to the actual writing of the Java based request handler.

<artifactId>aws-lambda-java-core</artifactId> <version>1.0.0</version> </dependency> Update your Java class · Open SplitSDK_Sample.java · Add these imports at the top: import com.amazonaws.services.lambda.runtime.Context; import com.amazonaws.services.lambda.runtime.RequestHandler; Modify the class declaration: public class SplitSDK_Sample implements RequestHandler<Object, String> { Move your main method code into handleRequest ·

For API details, see ListFunctions in AWS SDK for Java 2.x API Reference. ... Create an IAM role and Lambda function, then upload handler code.

The aws-lambda-java-core library provides a logger class named LambdaLogger that you can access from the context object. The logger class supports multiline logs. The following example uses the LambdaLogger logger provided by the context object. // Handler value: example.Handler public class ...

Latest version of com.amazonaws:aws-lambda-java-core · https://javadoc.io/doc/com.amazonaws/aws-lambda-java-core · Current version 1.2.1 · https://javadoc.io/doc/com.amazonaws/aws-lambda-java-core/1.2.1 · package-list path (used for javadoc generation -link option) https://javadoc.io/doc/com.amazonaws/aws-lambda-java-core/1.2.1/package-list ·