Do you need to format a string representation for Credential? Because I don’t have that exact format template anymore, but it’s hardly rocket science to compose one. I’m going with Kotlin for Credential, leaving to you to adapt it to your specific use case and/or port it to Java:

"Credential — ID: ${credential.id}, Name: ${credential.name}, Password: ${credential.password}, Type: ${credential.type}"

Going off the top of my head so it may not work 100% but there is literally nothing obscure about creating such a string, I think.