Middleware Application Server

A middleware application server provides the services business applications need to run, including transactions, security, database connections, messaging, and clustering. In enterprise Java, Jakarta EE defines many of these services. When comparing application servers, check which Jakarta EE version each supports, its support lifecycle, and the licensing model to understand long-term costs.

Why the server under your Java apps matters more now

Java application servers don’t all support the same enterprise Java standards. That gap has become more noticeable as the standards evolve.

Jakarta EE 9, released in December 2020, renamed packages across the Jakarta EE specifications from javax.* to jakarta.*. IBM WebSphere traditional, for example, still supports Java EE 7, while Jakarta EE 11 shipped in June 2025.

Your server decides which version of the standard your apps can use and what you’ll pay to run them. It also affects how hard they’ll be to migrate later. So what does a middleware application server actually do, and how do you pick one that won’t hold you back?

Azul and Middleware Applications

Azul helps enterprises run Java in today’s AI-first world, with our technology used by 100% of the world’s top 10 trading companies.

Our December 2025 acquisition of Payara strengthened our ability to help teams migrate from legacy application servers like WebLogic and JBoss. The comparisons below draw on the trade-offs we discuss with customers planning a switch.

What is a middleware application server?

Middleware is software that sits between the operating system and your applications, providing services they need to run. An application server is one type of middleware. It runs your application code and manages shared services such as security, transactions, and database connections. For the basics, start with our guide to what an application server is.

In enterprise Java, application servers commonly implement Jakarta EE, a standard set of APIs for building enterprise applications. Previously known as Java EE, Jakarta EE defines services that application servers provide to deployed applications.

Its tutorial describes a Jakarta EE server as software that “runs the container, deploys applications into it, and provides administration”. The standard remains widely used: the Eclipse Foundation’s 2025 Jakarta EE Developer Survey found that 58% of its 1,703 respondents used Jakarta EE.

The shared services a middleware application server provides include:

• Transactions: Groups several steps into one all-or-nothing unit. In the Jakarta EE tutorial’s example, a funds transfer debits one account, credits another, and updates a log. Either all three happen, or none do.
• Connection pooling: Keeps a set of database connections open and ready, so each request doesn’t have to open a new one.
• Security: Checks who a user is and what they’re allowed to do before your code runs.
• Messaging: Passes work between applications through queues, so one app can hand off a job without waiting on the other.
• Clustering and failover: Runs your app across several server instances and sends users to a healthy instance when one fails.

Middleware application server vs. web server

A web server handles HTTP requests and delivers web pages and files. An application server goes further by running the business logic behind an application. For example, a web server can deliver a product page, but the application server checks stock and processes the order. In Java environments, it also manages services such as database connections, transactions, and security.

Apache HTTP Server and NGINX are common web servers. They can forward requests to an application server, but they don’t provide the same enterprise Java services.

In most production setups, you’ll run both. The web server takes incoming traffic at the front, then passes dynamic requests to the application server behind it. Our guide to web servers vs. application servers goes deeper on where each one fits.

Benefits of a middleware application server

1. Your developers spend their time on business logic

Without an application server, every team would end up writing its own code for transactions, connection pools, and login checks. And each version would come with its own bugs.

With one, a developer just marks which operations belong in a transaction, and the server commits or rolls them back. In Jakarta EE, that’s a single @Transactional annotation on a class or method. The vendor looks after that plumbing for every app on the server.

2. Your apps keep running when one server fails

You can run the same app on a cluster of server instances behind a load balancer. If one instance goes down, the load balancer sends its users to the others.

With session replication switched on, the server also copies each user’s session data across instances. So someone halfway through a checkout doesn’t get logged out and lose their cart. Setup varies by vendor, so it’s worth testing during a trial.

3. You can move between servers without starting over

Every certified server implements the same Jakarta EE APIs. So an app written to the standard can run on any server certified for that version.

That puts you in a stronger spot at renewal time, because you’re free to switch. You’ll still have some work to do, since vendor-specific deployment descriptors and admin scripts need converting.

How WebLogic, WebSphere, JBoss, and Payara compare

Each server supports a different Jakarta EE version, and that’s the first thing to compare. The table shows where they stood in October 2026.

1. Oracle WebLogic Server

Oracle WebLogic Server is Oracle’s Java application server. WebLogic 15.1.1 came out in October 2025 and supports Jakarta EE 9.1 on JDK 17 and 21. That puts it on the jakarta.* namespace, though it doesn’t support Jakarta EE 10 or 11 yet.

The previous release, 14.1.2, still supports Jakarta EE 8 and the javax.* names. Oracle’s price list puts Enterprise Edition at $25,000 per processor, plus $5,500 a year for support.

2. IBM WebSphere Application Server

IBM WebSphere comes with two runtimes. WebSphere traditional supports Java EE 7 on Java SE 8, and its latest fix pack, 9.0.5.29, shipped in September 2026. IBM says there’s no planned end-of-support date for versions 8.5.5 and 9.0.5.

WebSphere Liberty is IBM’s lighter, modular runtime, and it’s been certified for Jakarta EE 11 since May 2026. One WebSphere license covers both runtimes. IBM doesn’t publish a list price, so you’ll need a quote from IBM or a partner.

3. Red Hat JBoss EAP

Red Hat JBoss Enterprise Application Platform (EAP) is Red Hat’s supported product built from WildFly, the open-source application server. EAP 8.1 is Jakarta EE 10 compatible and runs on JDK 17 and 21.

Like Oracle, Red Hat publishes its prices, and subscriptions start at $8,800 for a year of Standard support. EAP 8 gets full support until February 2028. If you’re still on EAP 7, regular support ended on June 30, 2025, and only paid extended life support remains.

4. Azul Payara Server

Azul Payara Server is a fully supported middleware application server for running Jakarta EE and Java EE applications in production. It started out in 2014, derived from GlassFish. Payara 7 came out in May 2026. It’s certified for Jakarta EE 11 (Full Platform and Web Profile) and runs on Java 21 and 25.

We still support older versions, too, including Payara 5 for apps on Java EE 8 and javax.*. Clustering runs on our Domain Data Grid, which is on by default and can replicate user sessions across instances. We quote pricing per vCore, and the free Azul Payara Community edition covers development and testing.

How to choose a middleware application server

1. Start with the Jakarta EE version your code is written for

Check your imports before you check anyone’s feature list. If your code still uses javax.* packages, it was written for Java EE 8 or earlier. It’ll run on servers that still support those versions. But upgrading to Jakarta EE 9 or later means renaming those imports first.

If you’re already on Jakarta EE 9 or later, look up each server’s certified version on the Jakarta EE compatibility list. An app that uses Jakarta EE 10 APIs won’t run on a server that tops out at 9.1.

2. Add up the full cost, including how long support lasts

Licensing models differ more than features do, so run the numbers on your own setup. For example, Oracle prices WebLogic per processor.

If your servers count as eight Oracle processors, Enterprise Edition costs $200,000 in licenses at list price. On top of that, support adds $44,000 a year. Red Hat sells JBoss EAP as yearly subscriptions in 2-core and 4-core bands, and IBM quotes WebSphere through its reps.

Then check the support calendar. Under Oracle’s lifetime support policy, Premier Support for WebLogic 12.2.x ends in December 2026. If you run past a date like that, you’ll usually end up paying extra for extended support, so plan ahead.

3. Map your migration path, then test it on one app

Once you know where you’re headed, try the migration on one low-risk app before you touch the rest. When the Jakarta EE version stays the same, the work is mostly configuration, like data sources and security settings.

If you’re coming off WebLogic, our WebLogic vs. Payara comparison lays out the features side by side. WebLogic 14.1.2 apps can migrate to Payara 5 without a rewrite, since both use the javax.* namespace. Apps on 15.1.1 can migrate to Payara 6. And if you’d like a second opinion before you commit, we offer a free WebLogic Modernization Assessment.

Pick the server that fits where your apps are going

A middleware application server is the layer your Java apps lean on for transactions, security, and uptime. You’ll likely live with your choice for years, so start with the Jakarta EE version your apps need. Then check the support dates and get a price for your own core count.

If you’re planning to leave WebLogic, WebSphere, or JBoss, talk to one of our technical consultants about Azul Payara Server.

FAQs

1. Is Tomcat an application server?

Apache Tomcat is a servlet container, which makes it a partial application server. It implements six Jakarta EE specifications, including Servlet, Pages, and WebSocket, but it isn’t certified for the full platform. That’s plenty for many web apps. But if you need distributed transactions, messaging, or Enterprise Beans, you’ll want a full application server.

2. What is the difference between Java EE and Jakarta EE?

Jakarta EE is Java EE under new ownership and a new name. Oracle handed Java EE over to the Eclipse Foundation. Then in 2018, the community voted for the Jakarta EE name. Jakarta EE 8 matched Java EE 8 exactly. The big break came with Jakarta EE 9, which renamed the APIs from javax.* to jakarta.*.

3. What does “Jakarta EE compatible” mean?

Jakarta EE compatible means a server has passed the official Technology Compatibility Kit (TCK) for a given Jakarta EE version. The TCK is a test suite that checks whether a server behaves the way the specification says it should. You can look up any server on the Jakarta EE compatibility list, which groups products by version and profile.

4. Is WebLogic middleware?

Yes. WebLogic Server is Oracle’s middleware application server, and WebLogic 14.1.2 ships as part of Oracle Fusion Middleware 14.1.2. Oracle released WebLogic 15.1.1 as a standalone product in October 2025.