AWS Lambda Applications and NodeJS


I noticed that NodeJS is the only runtime option when creating an application.

Is there a reason that NodeJS is the only option? I've heard that NodeJS is able to cold start faster than Java for lambdas. I also noticed the example Java lambda project defaults to 512MB MemorySize and NodeJS defaults to 128MB. Is Amazon trying to push us to NodeJS when building lambda applications because it's a better language for the environment?

Is it possible to create a Java lambda resource within the template.yml of an application? Do I need to build the classfiles and upload them manually?

The java-test folder in my project has this structure


I've tried the following Resource configuration, but the example.Handler class cannot be found.

    Type: AWS::Serverless::Function
      CodeUri: java-test/
      Handler: example.Handler
      Runtime: java11
      Description: Java function
      MemorySize: 512
      Timeout: 10
      # Function's execution role
        - AWSLambdaBasicExecutionRole
        - AWSLambda_ReadOnlyAccess
        - AWSXrayWriteOnlyAccess
        - AWSLambdaVPCAccessExecutionRole
      Tracing: Active

I copied parts of the blank-java lambda project below.

Here's the full build output

docker ps
"C:\Program Files\Amazon\AWSSAMCLI\bin\sam.cmd" build javaTest --template C:\Users\bensi\IdeaProjects\team-up\template.yml --build-dir C:\Users\bensi\IdeaProjects\team-up\.aws-sam\build --use-container
Starting Build inside a container
Building codeuri: C:\Users\bensi\IdeaProjects\team-up\java-test runtime: java11 metadata: {} architecture: x86_64 functions: ['javaTest']

Fetching Docker container image......
Mounting C:\Users\bensi\IdeaProjects\team-up\java-test as /tmp/samcli/source:ro,delegated inside runtime container

Build Succeeded

Built Artifacts  : .aws-sam\build
Built Template   : .aws-sam\build\template.yaml

Commands you can use next
[*] Invoke Function: sam local invoke
[*] Test Function in the Cloud: sam sync --stack-name {stack-name} --watch
[*] Deploy: sam deploy --guided
Running JavaGradleWorkflow:GradleBuild
Running JavaGradleWorkflow:CopyArtifacts
"C:\Program Files\Amazon\AWSSAMCLI\bin\sam.cmd" local invoke javaTest --template C:\Users\bensi\IdeaProjects\team-up\.aws-sam\build\template.yaml --event "C:\Users\bensi\AppData\Local\Temp\[Local] javaTest-event5.json"
Invoking example.Handler (java11)
Skip pulling image and use local one:

Mounting C:\Users\bensi\IdeaProjects\team-up\.aws-sam\build\javaTest as /var/task:ro,delegated inside runtime container
START RequestId: 3e9debb6-a640-4ba2-bd6e-5f2d818d303e Version: $LATEST
{"errorMessage":"Class not found: example.Handler","errorType":"java.lang.ClassNotFoundException"}Class not found: example.Handler: java.lang.ClassNotFoundException
java.lang.ClassNotFoundException: example.Handler. Current classpath: file:/var/task/:file:/var/task/lib/aws-lambda-java-core-1.2.1.jar:file:/var/task/lib/gson-2.8.6.jar

END RequestId: 3e9debb6-a640-4ba2-bd6e-5f2d818d303e
REPORT RequestId: 3e9debb6-a640-4ba2-bd6e-5f2d818d303e	Init Duration: 0.07 ms	Duration: 271.19 ms	Billed Duration: 272 ms	Memory Size: 512 MB	Max Memory Used: 512 MB	

asked a year ago106 views
2 Answers

You can use AWS Serverless Application Model (AWS SAM) to create application locally and deploy it to AWS.

AWS SAM CLI allows to create applications for a wide range of Lambda runtimes (Java/.NET/NodeJS/Python/Go/Ruby). sam init -r java11, for example, will guide you through creating a new Java11 application from an AWS Quick Start Template or a custom one, if you have any. If you choose to use an AWS provided Quick start application (e.g. sam init --name java11-demo-app --runtime java11 --dependency-manager gradle --app-template hello-world) will have template.yaml file created for you, so that you can just build and deploy the demo app without writing any code.

answered a year ago
  • I created the demo app and copied over the files in ./gradle/wrapper/. It looks like the gradle jar needs to be uploaded with the source code of the project, but it's only 54KB so that's not too bad. I'll be checking out more of these quick start templates for other languages too. Thanks!

  • I spoke too soon. I was able to upload the project, but when I invoke it I get the same error.

    Class not found: helloworld.App: java.lang.ClassNotFoundException
    java.lang.ClassNotFoundException: helloworld.App. Current classpath: file:/var/task/

    Here's the source code of the project I'm playing with

    BTW when I run this project locally with sam build && sam local start-api --host I can invoke the Java endpoint and get the response back. It throws the class not found error when deployed to AWS.


You can use Java. You should look into provisioned concurrency as well to avoid cold start problems. I don't use Java with Lambda so I can't be of much more help beyond these links:

answered a year ago

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