try-catch-finally block in java

Question

As per my understanding, I want to follow the best practice for releasing the resources at the end to prevent any connection leaks. Here is my code in HelperClass.

public static DynamoDB getDynamoDBConnection()
{   
    try
    {
        dynamoDB = new DynamoDB(new AmazonDynamoDBClient(new ProfileCredentialsProvider()));
    }
    catch(AmazonServiceException ase)
    {
        //ase.printStackTrace();
        slf4jLogger.error(ase.getMessage());
        slf4jLogger.error(ase.getStackTrace());
        slf4jLogger.error(ase);
    }
    catch (Exception e)
    {
        slf4jLogger.error(e);
        slf4jLogger.error(e.getStackTrace());
        slf4jLogger.error(e.getMessage());
    }
    finally
    {
        dynamoDB.shutdown();
    }
    return dynamoDB;
}

My doubt is, since the finally block will be executed no matter what, will the dynamoDB returns empty connection because it will be closed in finally block and then execute the return statement? TIA.

Answer 1

Your understanding is correct. dynamoBD.shutdown() will always execute before return dynamoDB.

I'm not familiar with the framework you're working with, but I would probably organize the code as follows:

public static DynamoDB getDynamoDBConnection()
        throws ApplicationSpecificException {   
    try {
        return new DynamoDB(new AmazonDynamoDBClient(
                                    new ProfileCredentialsProvider()));
    } catch(AmazonServiceException ase) {
        slf4jLogger.error(ase.getMessage());
        slf4jLogger.error(ase.getStackTrace());
        slf4jLogger.error(ase);
        throw new ApplicationSpecificException("some good message", ase);
    }
}

and use it as

DynamoDB con = null;
try {
    con = getDynamoDBConnection();
    // Do whatever you need to do with con
} catch (ApplicationSpecificException e) {
    // deal with it gracefully
} finally {
    if (con != null)
        con.shutdown();
}

You could also create an AutoCloseable wrapper for your dynamoDB connection (that calls shutdown inside close) and do

try (DynamoDB con = getDynamoDBConnection()) {
    // Do whatever you need to do with con
} catch (ApplicationSpecificException e) {
    // deal with it gracefully
}