Amazon S3在将对象从一个存储桶复制到另一个存储桶时会校验对象的ETag（entity tag）值以确保完整性。如果ETag值不匹配，则复制操作将失败。

以下是使用AWS SDK for Java v2进行S3存储桶复制的示例代码：

import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.CopyObjectRequest;
import software.amazon.awssdk.services.s3.model.CopyObjectResponse;

public class S3BucketCopy {

    public static void main(String[] args) {

        String sourceBucket = "source-bucket";
        String sourceKey = "example-file.txt";
        String destinationBucket = "destination-bucket";
        String destinationKey = "example-file-copy.txt";

        Region region = Region.US_WEST_2;

        S3Client s3client = S3Client.builder()
                .credentialsProvider(ProfileCredentialsProvider.create())
                .region(region)
                .build();

        CopyObjectRequest copyObjectRequest = CopyObjectRequest.builder()
                .copySource(sourceBucket+"/"+sourceKey)
                .destinationBucket(destinationBucket)
                .destinationKey(destinationKey)
                .build();

        CopyObjectResponse copyObjectResponse = s3client.copyObject(copyObjectRequest);

        System.out.println("Copy status code: "+copyObjectResponse.sdkHttpResponse().statusCode());
    }
}