aws dynamodb scans hang when run from rest webservice on tomcat

I have a rest webservice running on Apache tomcat. When I use the following code (an aws dynamodb scan )in one of the webserice methods, it just hangs

DynamoDBScanExpression scanExpression = new DynamoDBScanExpression();

    scanExpression.addFilterCondition("Description", 
            new Condition()
                .withComparisonOperator(ComparisonOperator.CONTAINS)
                .withAttributeValueList(new AttributeValue().withS(desc)));
    PaginatedList<Product> scanResult = mapper.parallelScan(Product.class, scanExpression,3);
    return scanResult; 

But when I run it inside a java standalone application it is fine. Is there limitations on what can be run in a web service on tomcat? Are there other servers/containers that will run such code