You plan to migrate an on‑premises Linux server that hosts a Java application (App1) to Azure. App1 is an interactive HTTPS application whose connection count varies significantly during the day, runs multiple concurrent instances, and would require major changes to run in a container. The solution must run multiple instances of App1, automatically adjust the instance count based on load, and minimize administrative overhead. Which Azure compute service should you recommend?

Azure App Service is the best choice because it's a fully managed platform for hosting web applications, including Java apps. It natively supports automatic scaling based on load, which addresses the requirement for varying connection counts and minimizing administrative overhead. Its PaaS (Platform as a Service) nature means you don't manage the underlying infrastructure. Azure Batch is for large-scale parallel and high-performance computing, not interactive web applications. Azure Kubernetes Service (AKS) offers container orchestration, but the question states App1 would require major changes to run in a container, making AKS less suitable. Azure Virtual Machine Scale Sets provide IaaS (Infrastructure as a Service) scalability for VMs, but App Service offers a higher level of abstraction and less administrative overhead for web applications.