A way to make requests to AWS that require assuming a role when using V1 of the AWS Java SDK.

MakingAssumeRoleRequests.java

package com.joelforjava.aws.assumerole.example;

import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicSessionCredentials;
import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.securitytoken.AWSSecurityTokenService;
import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceAsyncClientBuilder;
import com.amazonaws.services.securitytoken.model.AssumeRoleRequest;
import com.amazonaws.services.securitytoken.model.AssumeRoleResult;
import com.amazonaws.services.securitytoken.model.Credentials;

public class MakingAssumeRoleRequests {

    private static AWSCredentialsProvider loadCredentials(boolean isLocal) {
        final AWSCredentialsProvider credentialsProvider;
        if (isLocal) {
            AWSSecurityTokenService stsClient = AWSSecurityTokenServiceAsyncClientBuilder.standard()
                    .withCredentials(new ProfileCredentialsProvider("devjump"))
                    .withRegion("us-east-1")
                    .build();

            AssumeRoleRequest assumeRoleRequest = new AssumeRoleRequest().withDurationSeconds(3600)
                    .withRoleArn("arn:aws:iam::1234567890987:role/Super-Important-Role")
                    .withRoleSessionName("S3_Session");

            AssumeRoleResult assumeRoleResult = stsClient.assumeRole(assumeRoleRequest);
            Credentials creds = assumeRoleResult.getCredentials();

            credentialsProvider = new AWSStaticCredentialsProvider(
                    new BasicSessionCredentials(creds.getAccessKeyId(),
                            creds.getSecretAccessKey(),
                            creds.getSessionToken())
            );
        } else {
            credentialsProvider = new DefaultAWSCredentialsProviderChain();
        }

        return credentialsProvider;
    }

    public static void main(String[] args) {
        AWSCredentialsProvider credentialsProvider = loadCredentials(true);

        AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                .withCredentials(credentialsProvider)
                .withRegion("us-east-1")
                .build();

        ObjectListing objects = s3Client.listObjects("bucket-name");
        System.out.printf("No. of Objects: %s", objects.getObjectSummaries().size());
    }

}