The AWS SDK for Java 1.x reached end-of-support on December 31, 2025. We recommend that you migrate to the [AWS SDK for Java 2.x](https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/home.html) to continue receiving new features, availability improvements, and security updates.
# Invoking, Listing, and Deleting Lambda Functions
This section provides examples of programming with the Lambda service client by using the AWS SDK for Java. To learn how to create a Lambda function, see [How to Create AWS Lambda functions](https://docs.aws.amazon.com/toolkit-for-eclipse/v1/user-guide/lambda-tutorial.html).
**Topics**
+ [Invoke a function](#invoke-function)
+ [List functions](#list-function)
+ [Delete a function](#delete-function)
## Invoke a function
You can invoke a Lambda function by creating an [AWSLambda](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/AWSLambda.html) object and invoking its `invoke` method. Create an [InvokeRequest](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/model/InvokeRequest.html) object to specify additional information such as the function name and the payload to pass to the Lambda function. Function names appear as *arn:aws:lambda:us-east-1:555556330391:function:HelloFunction*. You can retrieve the value by looking at the function in the AWS Management Console.
To pass payload data to a function, invoke the [InvokeRequest](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/model/InvokeRequest.html) object’s `withPayload` method and specify a String in JSON format, as shown in the following code example.
**Imports**
```
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.lambda.AWSLambda;
import com.amazonaws.services.lambda.AWSLambdaClientBuilder;
import com.amazonaws.services.lambda.model.InvokeRequest;
import com.amazonaws.services.lambda.model.InvokeResult;
import com.amazonaws.services.lambda.model.ServiceException;
import java.nio.charset.StandardCharsets;
```
**Code**
The following code example demonstrates how to invoke a Lambda function.
```
String functionName = args[0];
InvokeRequest invokeRequest = new InvokeRequest()
.withFunctionName(functionName)
.withPayload("{\n" +
" \"Hello \": \"Paris\",\n" +
" \"countryCode\": \"FR\"\n" +
"}");
InvokeResult invokeResult = null;
try {
AWSLambda awsLambda = AWSLambdaClientBuilder.standard()
.withCredentials(new ProfileCredentialsProvider())
.withRegion(Regions.US_WEST_2).build();
invokeResult = awsLambda.invoke(invokeRequest);
String ans = new String(invokeResult.getPayload().array(), StandardCharsets.UTF_8);
//write out the return value
System.out.println(ans);
} catch (ServiceException e) {
System.out.println(e);
}
System.out.println(invokeResult.getStatusCode());
```
See the complete example on [Github](https://github.com/awsdocs/aws-doc-sdk-examples/blob/master/java/example_code/lambda/src/main/java/com/example/lambda/LambdaInvokeFunction.java).
## List functions
Build an [AWSLambda](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/AWSLambda.html) object and invoke its `listFunctions` method. This method returns a [ListFunctionsResult](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/model/ListFunctionsResult.html) object. You can invoke this object’s `getFunctions` method to return a list of [FunctionConfiguration](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/model/FunctionConfiguration.html) objects. You can iterate through the list to retrieve information about the functions. For example, the following Java code example shows how to get each function name.
**Imports**
```
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.lambda.AWSLambda;
import com.amazonaws.services.lambda.AWSLambdaClientBuilder;
import com.amazonaws.services.lambda.model.FunctionConfiguration;
import com.amazonaws.services.lambda.model.ListFunctionsResult;
import com.amazonaws.services.lambda.model.ServiceException;
import java.util.Iterator;
import java.util.List;
```
**Code**
The following Java code example demonstrates how to retrieve a list of Lambda function names.
```
ListFunctionsResult functionResult = null;
try {
AWSLambda awsLambda = AWSLambdaClientBuilder.standard()
.withCredentials(new ProfileCredentialsProvider())
.withRegion(Regions.US_WEST_2).build();
functionResult = awsLambda.listFunctions();
List list = functionResult.getFunctions();
for (Iterator iter = list.iterator(); iter.hasNext(); ) {
FunctionConfiguration config = (FunctionConfiguration)iter.next();
System.out.println("The function name is "+config.getFunctionName());
}
} catch (ServiceException e) {
System.out.println(e);
}
```
See the complete example on [Github](https://github.com/awsdocs/aws-doc-sdk-examples/blob/master/java/example_code/lambda/src/main/java/com/example/lambda/ListFunctions.java).
## Delete a function
Build an [AWSLambda](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/AWSLambda.html) object and invoke its `deleteFunction` method. Create a [DeleteFunctionRequest](https://docs.aws.amazon.com/sdk-for-java/v1/reference/com/amazonaws/services/lambda/model/DeleteFunctionRequest.html) object and pass it to the `deleteFunction` method. This object contains information such as the name of the function to delete. Function names appear as *arn:aws:lambda:us-east-1:555556330391:function:HelloFunction*. You can retrieve the value by looking at the function in the AWS Management Console.
**Imports**
```
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.lambda.AWSLambda;
import com.amazonaws.services.lambda.AWSLambdaClientBuilder;
import com.amazonaws.services.lambda.model.ServiceException;
import com.amazonaws.services.lambda.model.DeleteFunctionRequest;
```
**Code**
The following Java code demonstrates how to delete a Lambda function.
```
String functionName = args[0];
try {
AWSLambda awsLambda = AWSLambdaClientBuilder.standard()
.withCredentials(new ProfileCredentialsProvider())
.withRegion(Regions.US_WEST_2).build();
DeleteFunctionRequest delFunc = new DeleteFunctionRequest();
delFunc.withFunctionName(functionName);
//Delete the function
awsLambda.deleteFunction(delFunc);
System.out.println("The function is deleted");
} catch (ServiceException e) {
System.out.println(e);
}
```
See the complete example on [Github](https://github.com/awsdocs/aws-doc-sdk-examples/blob/master/java/example_code/lambda/src/main/java/com/example/lambda/DeleteFunction.java).