springboot schedular

 https://reflectoring.io/spring-scheduler/

Cron job scheduling example

 https://reflectoring.io/spring-scheduler/

Grouping by example

 public static void main(String arg[]) {

    final AtomicInteger counter = new AtomicInteger(0);
    List<Integer> questionsList = new ArrayList<>();
    for(Integer i=0;i<100;i++) {

        questionsList.add(i*2);
    }
    final Collection<List<Integer>> dividedByTenList = questionsList.stream()
            .collect(Collectors.groupingBy(it -> counter.getAndIncrement() / 10))
            .values();
    dividedByTenList.forEach(batchlist -> {
        System.out.println("hello pawan"+batchlist);
    });
}

verify cognito token

 https://openid.net/developers/jwt/

jose4j

• Open source implementation of JWT and the full JOSE suite. Developed by Brian Campbell.
• License: Apache 2.0
• Supports: JWT, JWS, JWE and JWK.
• Target Environment: Java 7 or 8

Nimbus JOSE+JWT

Map example

 https://www.callicoder.com/java-hashmap/

Aws example in java

 https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javav2/example_code

Access S3 data without credentials

use Aws\S3\S3Client;

 $provider = CredentialProvider::defaultProvider();

$s3Client = new S3Client(array(
    'version'     => 'latest',
    'region'      => env('lambda_region'),
    'credentials'=>$provider
));