The Kloudless Authentication Java Sample Code demonstrates how to use a bearer token authentication. The getting started guide includes Out-of-band OAuth Flow and 3-Legged OAuth Flow.
To help developers increase the security of their apps, PayPal has updated its developer portal to include a self-service credential provisioning feature that allows developers to generate their own client-secret pairs, which developers use to authenticate their apps with the PayPal API.
APIMatic, SDK generator, announced that its SDKs now support OAuth 2.0. Prior to this announcement, there was minimal support for OAuth 2.0 only for authentication token headers within requests. Now, the company is moving forward with full support and continued development.