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Your Cloud Run function runs in an environment consisting of an
operating system version with add-on packages, language support, and
theJava Functions Frameworklibrary that supports and invokes your function. This environment is identified
by the language version, and is known as the runtime ID.
Function preparation
You can prepare a function directly from the Google Cloud console or write it on
your local machine and upload it. To prepare your local machine for Java
development, seeSet up a Java development environment.
You can select one of the supported Java runtimes for your function during
deployment.
You can select a runtime version using the Google Cloud console, or the
gcloud CLI. Click the tab for instructions on using the tool of
your choice:
gcloud
Specify theJava base imagefor your function using the--base-imageflag,
while deploying your function. For example:
gcloud run deployFUNCTION\
--source . \
--functionFUNCTION_ENTRYPOINT\
--base-image java21
Replace:
FUNCTIONwith the name of the function you are
deploying. You can omit this parameter entirely,
but you will be prompted for the name if you omit it.
FUNCTION_ENTRYPOINTwith the entry point to your function in
your source code. This is the code Cloud Run executes when your
function runs. The value of this flag must be a function name or
fully-qualified class name that exists in your source code.
You can select a runtime version when you create or update a Cloud Run function in the Google Cloud console. For detailed
instructions on deploying a function, seeDeploy functions in Cloud Run.
To select a runtime in the Google Cloud console when you create a function, follow these steps:
In the Google Cloud console, go to the Cloud Run page:
ClickCreate, and wait for Cloud Run to create the service
using a placeholder revision.
The console will redirect you to theSourcetab where you can see the source code of your function. ClickSave and redeploy.
For detailed instructions on updating the runtime version after your function is
deployed, seeRe-deploy new source code.
Source code structure
For Cloud Run functions to find your function's definition, your
source code must follow a specific structure. SeeWrite Cloud Run functionsfor
more information.
Your Java runtime automatically sets certain environment variables for your
function to use as needed. For details, seeConfigure environment
variables.
Execution ID
For Java functions that usefunctions-frameworkversion 1.4.0 or later, you
can use the logging classjava.util.logging.Loggerto add a unique execution
ID to log outputs. Usingstdoutorstderr(for example,System.println()) does not add the execution ID.
Note that:
If you created your function using theCloud Functions v2 API(for example, by usinggcloud functions, the REST API, or Terraform), this
execution ID is added automatically.
If you created your function using theCloud Run Admin API(for example, by using Google Cloud console,gcloud run, the REST API, or
Terraform), you need to set theLOG_EXECUTION_IDenvironment variable totrueto use this feature.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[],[],null,["# The Java runtime\n\nYour Cloud Run function runs in an environment consisting of an\noperating system version with add-on packages, language support, and\nthe [Java Functions Framework](https://github.com/GoogleCloudPlatform/functions-framework-java)\nlibrary that supports and invokes your function. This environment is identified\nby the language version, and is known as the runtime ID.\n\nFunction preparation\n--------------------\n\nYou can prepare a function directly from the Google Cloud console or write it on\nyour local machine and upload it. To prepare your local machine for Java\ndevelopment, see [Set up a Java development environment](/java/docs/setup).\n\nSupported Java runtimes and base images\n---------------------------------------\n\nSelect your runtime\n-------------------\n\nYou can select one of the supported Java runtimes for your function during\ndeployment.\n\n\nYou can select a runtime version using the Google Cloud console, or the\ngcloud CLI. Click the tab for instructions on using the tool of\nyour choice: \n\n### gcloud\n\nSpecify the [Java base image](/run/docs/configuring/services/runtime-base-images#how_to_obtain_base_images) for your function using the `--base-image` flag,\nwhile deploying your function. For example: \n\n gcloud run deploy \u003cvar translate=\"no\"\u003eFUNCTION\u003c/var\u003e \\\n --source . \\\n --function \u003cvar translate=\"no\"\u003eFUNCTION_ENTRYPOINT\u003c/var\u003e \\\n --base-image java21\n\nReplace:\n\n- \u003cvar translate=\"no\"\u003eFUNCTION\u003c/var\u003e with the name of the function you are\n deploying. You can omit this parameter entirely,\n but you will be prompted for the name if you omit it.\n\n- \u003cvar translate=\"no\"\u003eFUNCTION_ENTRYPOINT\u003c/var\u003e with the entry point to your function in\n your source code. This is the code Cloud Run executes when your\n function runs. The value of this flag must be a function name or\n fully-qualified class name that exists in your source code.\n\nFor detailed instructions on deploying a function using the gcloud CLI, see [Deploy functions in Cloud Run](/run/docs/deploy-functions#gcloud).\n\n### Console\n\nYou can select a runtime version when you create or update a Cloud Run function in the Google Cloud console. For detailed\ninstructions on deploying a function, see [Deploy functions in Cloud Run](/run/docs/deploy-functions#deploy-functions).\n\nTo select a runtime in the Google Cloud console when you create a function, follow these steps:\n\n1. In the Google Cloud console, go to the Cloud Run page:\n\n [Go to Cloud Run](https://console.cloud.google.com/run)\n2. Click **Write a function**.\n\n3. In the **Runtime** list, select a Java runtime version.\n\n4. Click **Create**, and wait for Cloud Run to create the service\n using a placeholder revision.\n\n5. The console will redirect you to the **Source**\n tab where you can see the source code of your function. Click **Save and redeploy**.\n\nFor detailed instructions on updating the runtime version after your function is\ndeployed, see\n[Re-deploy new source code](/run/docs/deploy-functions#update-code-functions).\n\nSource code structure\n---------------------\n\nFor Cloud Run functions to find your function's definition, your\nsource code must follow a specific structure. See\n[Write Cloud Run functions](/run/docs/write-functions#java) for\nmore information.\n\nSpecifying dependencies\n-----------------------\n\nYou can specify dependencies for your function using [Maven](https://maven.apache.org)\nor [Gradle](https://gradle.org). For more information, see [Specify\ndependencies in Java](/run/docs/runtimes/java-dependencies).\n\nEnvironment variables\n---------------------\n\nYour Java runtime automatically sets certain environment variables for your\nfunction to use as needed. For details, see [Configure environment\nvariables](/run/docs/configuring/services/environment-variables).\n\nExecution ID\n------------\n\nFor Java functions that use `functions-framework` version 1.4.0 or later, you\ncan use the logging class `java.util.logging.Logger` to add a unique execution\nID to log outputs. Using `stdout` or `stderr` (for example,\n`System.println()`) does not add the execution ID.\n\nNote that:\n\n- If you created your function using the\n [Cloud Functions v2 API](/functions/docs/reference/rest)\n (for example, by using `gcloud functions`, the REST API, or Terraform), this\n execution ID is added automatically.\n\n- If you created your function using the\n [Cloud Run Admin API](/run/docs/reference/cloud-run-admin-api-overview)\n (for example, by using Google Cloud console, `gcloud run`, the REST API, or\n Terraform), you need to set the `LOG_EXECUTION_ID` environment variable to\n `true` to use this feature."]]
