AWS Secrets Manager SecretCache Java v2

The latest SDK documentation can be found here, within that documentation there's the following:

We recommend that you cache your secret values by using client-side caching. Caching secrets improves speed and reduces your costs. For more information, see Cache secrets for your applications.

That link leads you to the page you provided above, so it stands within reason that you're still able to use secret caching in V2.

It looks like SDK 1.x is required:

To use the component, you must have the following:

A Java 8 or higher development environment. See Java SE Downloads on the Oracle website. The AWS SDK 1.x for Java. You can use both versions of the AWS SDK for Java in your projects. For more information, see Using the SDK for Java 1.x and 2.x side-by-side.