Azure offers many options for teams to build and deploy Java applications. This article covers mainstream scenarios for Java on Azure and provides high-level planning suggestions and considerations.
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Platform
Before you select a cloud scenario for your Java application, identify its platform. Most Java applications use one of the following platforms:
Spring Boot JAR applications
Spring Boot JAR applications are typically invoked directly from the command line. They handle web requests. Instead of relying on an application server to handle HTTP requests, these applications incorporate HTTP communication and other dependencies directly into the application package. Such applications are often built with frameworks such as Spring Boot, Dropwizard, Micronaut, MicroProfile, and Vert.x.
These applications are packaged into archives that have the .jar extension, known as JAR files.
Spring Cloud applications
The microservice architectural style is an approach to developing a single application as a suite of small services. Each service runs in its own process and communicates by using lightweight mechanisms, often an HTTP resource API. These services are built around business capabilities.
Automated deployment machinery independently deploys these microservices. There's a minimum of centralized management, which might be written in different programming languages and use different data storage technologies. Such services are often built with frameworks such as Spring Cloud.
These services are packaged into multiple applications as JAR files.
Web applications
Web applications run inside a servlet container. Some use servlet APIs directly, while others use other frameworks that encapsulate servlet APIs, such as Apache Struts, Spring MVC, and JavaServer Faces.
Web applications are packaged into archives that have the .war extension, known as WAR files.
Jakarta EE applications
Jakarta Enterprise Edition (Jakarta EE) applications can contain some, all, or none of the elements of web applications. They can also contain and consume many more components, as defined by the Jakarta EE specification. Jakarta EE applications were formerly known as Java EE applications or J2EE applications.
Jakarta EE applications can be packaged as WAR files or as archives that have the .ear extension, known as EAR files.
Jakarta EE applications must be deployed onto application servers that are Jakarta EE compliant. Examples include WebLogic, WebSphere, WildFly, GlassFish, and Payara.
Applications that rely only on features provided by the Jakarta EE specification can be migrated from one compliant application server onto another. If your application is dependent on a specific application server, you might need to select an Azure service destination that permits you to host that application server.
Platform options
Use the following table to identify potential platforms for your application type.
| Azure Spring Apps | App Service Java SE | App Service Tomcat | App Service JBoss EAP | Azure Container Apps | AKS | Virtual Machines | |
|---|---|---|---|---|---|---|---|
| Spring Boot / JAR applications | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | |
| Spring Cloud applications | ✔ | ✔ | ✔ | ✔ | |||
| Web applications | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | |
| Jakarta EE applications | ✔ | ✔ | ✔ | ||||
| Azure region availability | Details | Details | Details | Details | Details | Details | Details |
Azure Kubernetes Service (AKS) and Virtual Machines support all application types, but they require that your team to take on more responsibilities, as described in the next section.
Supportability
Besides the platform choices, modern Java applications might have other supportability needs, such as:
Batch or scheduled jobs
Instead of waiting for requests or user input, some applications run briefly, run a particular workload, and then exit. Sometimes, such jobs need to run once or at regular, scheduled intervals. On-premises, such jobs are often invoked from a server's cron table.
These applications are packaged as JAR files.
Note
If your application uses a scheduler, such as Spring Batch or Quartz, to run scheduled tasks, we strongly recommend that you run those tasks outside of the application. If your application scales to multiple instances in the cloud, the same job can run more than once. If your scheduling mechanism uses the host's local time zone, there might be undesired behavior when you scale an application across regions.
Virtual network integration
When you deploy a Java application in your virtual network, it has outbound dependencies on services outside of the virtual network. For management and operations, your project must have access to certain ports and fully qualified domain names. With Azure Virtual Networks, you can place many of your Azure resources in a non-internet routable network. The virtual network integration feature enables your applications to access resources in or through a virtual network. Virtual network integration doesn't enable your applications to be accessed privately.
Serverless development model
Serverless is a cloud-native development model that allows developers to build and run applications without having to manage servers. With serverless applications, the cloud service provider automatically provisions, scales, and manages the infrastructure required to run the code. Servers still exist in the serverless model. They're abstracted away from application development.
Containerization
Containerization is the packaging together of software code with all its necessary components, like libraries, frameworks, and other dependencies. The application is isolated in its own container.
CI/CD
Continuous integration and continuous delivery (CI/CD) is a method to frequently deliver applications to customers by introducing automation into the stages of application development. The main concepts in CI/CD are continuous integration, continuous delivery, and continuous deployment. All of the Azure choices support most CI/CD tooling. For example, you might use solutions such as Azure Pipelines or Jenkins.
Open-source search engine
Searches are integral parts of any application. If speed, performance, and high availability are critical, searches on terabytes and petabytes of data can be challenging. When you host Java applications on Azure, plan to host your related Solr and Elasticsearch instances. Alternatively, consider migrating to Azure Cognitive Search.
Big data tools
Big data tools enable the automation of data flow among the software systems. They support scalable, robust, and streamlined data routing graphs along with system mediation logic. They're utilized to build live data flow pipelines and stream applications. Learn how Nifi and Apache Kafka on Azure might be suitable for your needs.
Supportability options
Use the following table to identify potential options for your application type. AKS and Virtual Machines support all application types, but they require your team to take on more responsibilities.
| Azure Spring Apps | App Service Java SE | App Service Tomcat | App Service JBoss EAP | Azure Container Apps | AKS | Virtual Machines | |
|---|---|---|---|---|---|---|---|
| Batch or scheduled jobs | ✔ | ✔ | ✔ | ✔ | |||
| Virtual network integration | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
| Serverless | ✔ | ✔ | ✔ | ✔ | |||
| Containerization | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ |
| Azure region availability | Details | Details | Details | Details | Details | Details | Details |
Also, refer to this decision tree.
Download a Visio file of this diagram.
Build or migrate Java applications
To build or migrate the Java applications, identify the Java platform of your applications. Some popular platforms are Java SE, Jakarta EE, and MicroProfile.
Java SE
Java Platform, Standard Edition (Java SE) is a computing platform for the development and deployment of portable code for desktop and server environments. Popular projects built on Java SE include Spring Boot, Spring Cloud, Spring Framework, and Apache Tomcat.
Jakarta EE
Jakarta EE is the open source future of cloud-native enterprise Java. It's a set of specifications that extend Java SE with enterprise features such as distributed computing and web services. Jakarta EE applications run reference runtimes. These runtimes can be microservices or application servers. They handle transactions, security, scalability, concurrency, and management of the components the application deploys.
MicroProfile
The MicroProfile project provides a collection of specifications designed to help developers build Enterprise Java cloud-native microservices. Quarkus and Open Liberty are popular implementations of MicroProfile.
Build or migrate summary
The following table provides build or migration information by application type and Azure service.
| Type | Java SE | MicroProfile | JarkartaSE | |
|---|---|---|---|---|
| Virtual Machine | IaaS | ✔ | ✔ | ✔ |
| VMware Tanzu | IaaS | ✔ | ||
| Azure Kubernetes Service | Container | ✔ | ✔ | ✔ |
| Red Hat OpenShift | Container | ✔ | ✔ | ✔ |
| Azure Container App | PaaS | ✔ | ✔ | |
| JBoss EAP | PaaS App Service | ✔ | ✔ | |
| Apache Tomcat | PaaS App Service | ✔ | ||
| Java SE | PaaS App Service | ✔ | ✔ | |
| Azure Spring Apps | PaaS | ✔ |
Contributors
This article is maintained by Microsoft. It was originally written by the following contributors.
Principal authors:
- Asir Vedamuthu Selvasingh | Principal Program Manager
- Hang Wang | Product Manager
- Xinyi Zhang | Principal PM Manager
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Next steps
- Azure Container Apps overview
- Azure Kubernetes Service
- Azure Spring Apps documentation
- Azure Virtual network integration
- Virtual machines in Azure