How to list all AWS S3 objects in a bucket using Java

ListKeysV1.java

public class ListKeysV1 {
	private static String bucketName = "***bucket name***";

    public static void main(String[] args) throws IOException {
    	AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());        

        ListObjectsRequest listObjectsRequest = new ListObjectsRequest()
            .withBucketName(bucketName)
            .withPrefix("m");
        ObjectListing objectListing;

        do {
                objectListing = s3client.listObjects(listObjectsRequest);
                for (S3ObjectSummary objectSummary : 
                    objectListing.getObjectSummaries()) {
                    System.out.println( " - " + objectSummary.getKey() + "  " +
                            "(size = " + objectSummary.getSize() + 
                            ")");
                }
                listObjectsRequest.setMarker(objectListing.getNextMarker());
        } while (objectListing.isTruncated());
    }
}

ListKeysV2.java

public class ListKeys {
    private static String bucketName = "***bucket name***";

    public static void main(String[] args) throws IOException {
        AmazonS3 s3client = new AmazonS3Client(new ProfileCredentialsProvider());
        try {
            System.out.println("Listing objects");
            final ListObjectsV2Request req = new ListObjectsV2Request().withBucketName(bucketName);
            ListObjectsV2Result result;
            do {               
               result = s3client.listObjectsV2(req);

               for (S3ObjectSummary objectSummary : 
                   result.getObjectSummaries()) {
                   System.out.println(" - " + objectSummary.getKey() + "  " +
                           "(size = " + objectSummary.getSize() + 
                           ")");
               }
               System.out.println("Next Continuation Token : " + result.getNextContinuationToken());
               req.setContinuationToken(result.getNextContinuationToken());
            } while(result.isTruncated() == true ); 

         } catch (AmazonServiceException ase) {
            System.out.println("Caught an AmazonServiceException, " +
                    "which means your request made it " +
                    "to Amazon S3, but was rejected with an error response " +
                    "for some reason.");
            System.out.println("Error Message:    " + ase.getMessage());
            System.out.println("HTTP Status Code: " + ase.getStatusCode());
            System.out.println("AWS Error Code:   " + ase.getErrorCode());
            System.out.println("Error Type:       " + ase.getErrorType());
            System.out.println("Request ID:       " + ase.getRequestId());
        } catch (AmazonClientException ace) {
            System.out.println("Caught an AmazonClientException, " +
                    "which means the client encountered " +
                    "an internal error while trying to communicate" +
                    " with S3, " +
                    "such as not being able to access the network.");
            System.out.println("Error Message: " + ace.getMessage());
        }
    }
}