Java

Upload, download and share files from Java with the AWS SDK for Java 2.x.

The AWS SDK for Java 2.x works with Zata. Point the S3 client at the Zata endpoint, and you can use the normal S3 calls from Java, including Spring Boot apps.

Tested with the AWS SDK for Java 2.46.7 (software.amazon.awssdk:s3) on Java 21 on Zata in October 2026.

Before you start

• A bucket. See Create a bucket.
• An access key and secret key from the same region as the bucket. See Access keys.

Connection settings

Setting	Value
endpointOverride	https://idr01.zata.ai for Indore, https://bom01.zata.ai for Mumbai
region	Region.US_EAST_1
Access key / Secret key	from Access Keys in the Zata console. The key must be from the same region as the bucket.
forcePathStyle	true
requestChecksumCalculation / responseChecksumValidation	WHEN_REQUIRED

Add the SDK

Maven

<dependency>
  <groupId>software.amazon.awssdk</groupId>
  <artifactId>s3</artifactId>
  <version>2.46.7</version>
</dependency>

Gradle

implementation("software.amazon.awssdk:s3:2.46.7")

Create the client

Keep your keys out of the code. Put them in environment variables; the SDK reads them by itself:

export AWS_ACCESS_KEY_ID=YOUR_ACCESS_KEY
export AWS_SECRET_ACCESS_KEY=YOUR_SECRET_KEY

Then create the client. For a bucket in Mumbai, use https://bom01.zata.ai.

import java.net.URI;
import software.amazon.awssdk.core.checksums.RequestChecksumCalculation;
import software.amazon.awssdk.core.checksums.ResponseChecksumValidation;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;

S3Client s3 = S3Client.builder()
    .endpointOverride(URI.create("https://idr01.zata.ai"))
    .region(Region.US_EAST_1)
    .forcePathStyle(true)
    .requestChecksumCalculation(RequestChecksumCalculation.WHEN_REQUIRED)
    .responseChecksumValidation(ResponseChecksumValidation.WHEN_REQUIRED)
    .build();

The two WHEN_REQUIRED lines are required. With the SDK's default settings (version 2.30 and newer), every upload to Zata fails with XAmzContentSHA256Mismatch, even small files.

Upload, download and list files

import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.services.s3.model.*;

// Upload
s3.putObject(PutObjectRequest.builder().bucket("my-bucket").key("hello.txt").build(),
             RequestBody.fromString("hello from java"));

// Download
String text = s3.getObjectAsBytes(GetObjectRequest.builder().bucket("my-bucket").key("hello.txt").build())
                .asUtf8String();

// Count the files in the bucket
int count = s3.listObjectsV2(ListObjectsV2Request.builder().bucket("my-bucket").build()).keyCount();

To upload a file from disk, use RequestBody.fromFile(Paths.get("myfile.txt")) (with import java.nio.file.Paths;).

List your buckets

s3.listBuckets().buckets().forEach(b -> System.out.println(b.name()));

A sub-user's key gets an empty list here, even for buckets it can use. Use the bucket name directly.

Make a download link

A presigned URL lets someone download one file without keys, until the link expires.

import java.time.Duration;
import software.amazon.awssdk.services.s3.S3Configuration;
import software.amazon.awssdk.services.s3.presigner.S3Presigner;
import software.amazon.awssdk.services.s3.presigner.model.GetObjectPresignRequest;

try (S3Presigner presigner = S3Presigner.builder()
        .endpointOverride(URI.create("https://idr01.zata.ai"))
        .region(Region.US_EAST_1)
        .serviceConfiguration(S3Configuration.builder().pathStyleAccessEnabled(true).build())
        .build()) {
    String url = presigner.presignGetObject(GetObjectPresignRequest.builder()
            .signatureDuration(Duration.ofMinutes(10))
            .getObjectRequest(GetObjectRequest.builder().bucket("my-bucket").key("hello.txt").build())
            .build()).url().toString();
}

Anyone who has the link can use it until it expires, so share it only with the intended person.

Troubleshooting

Problem	Fix
XAmzContentSHA256Mismatch on every upload	Add the two WHEN_REQUIRED lines to the client. Or set the environment variables AWS_REQUEST_CHECKSUM_CALCULATION=when_required and AWS_RESPONSE_CHECKSUM_VALIDATION=when_required.
InvalidAccessKeyId	endpointOverride is missing (requests go to AWS), or the key is from the other region.
NoSuchBucket	Use the endpoint of the region the bucket is in.
The bucket list is empty	A sub-user's key cannot list buckets. Use the bucket name directly.

For other errors, see Large uploads and Wrong endpoint or region.