History of Oracle Enterprise Manager (OEM) and transition from Java-based interface to browser-based

Transition Away from Java-Based Interface Oracle Enterprise Manager originally started as a Java-based client application, specifically with the Oracle Enterprise Manager Database Control in earlier versions like Oracle 8i and 9i. This Java client required a local installation or a Java plugin to run through a browser, allowing administrators to manage databases and related systems. Over time, Oracle shifted toward a more modern, web-based approach to improve accessibility, reduce dependency on Java plugins, and align with industry trends. The significant move away from the Java-based interface began with Oracle Enterprise Manager Grid Control 10g^[1] (circa 2003-2004), which introduced a web-based console as an option alongside the Java client. However, the Java-based interface persisted as a primary or alternative option in some releases. The full transition to a predominantly browser-based interface occurred with Oracle Enterprise Manager Cloud Control 12c (released in 2011). This version, specifically 12c Release 1 (12.1.0.1), marked a pivotal shift where the Oracle Management Service (OMS) became a fully web-based application deployed on Oracle WebLogic Server. The Java client was effectively phased out as the primary management interface, though some Java-based components (like plugins or diagnostics) remained in use behind the scenes or as optional tools. Thus, the version that "did away" with the Java-based interface as the primary management tool was Oracle Enterprise Manager Cloud Control 12c. Earlier versions, such as 11g Grid Control, still supported Java-based elements, but 12c solidified the browser-based approach with a modern, scalable architecture.
Oracle 12c refers to the Oracle Database 12c release (first available in 2013 with 12.1.0.1), and it's important to distinguish this from the broader Oracle Enterprise Manager product timeline. Oracle Enterprise Manager has its own versioning (i.e., 10g, 11g, 12c Cloud Control), which doesn’t always align with database releases.

• Oracle 8i (circa 1998): Oracle Enterprise Manager Database Control was indeed a Java-based client application at this stage. It required a standalone Java console or a browser with a Java plugin to operate, as web technologies were less mature at the time.
• Pre-12c Evolution: The shift to a browser-based interface began earlier than Oracle Database 12c. With OEM Grid Control 10g (2003) and 11g (2010), Oracle introduced web-based management consoles that ran through a browser without requiring a Java client for core functionality. These versions used Oracle Application Server or WebLogic Server to host the web interface, though some administrative tasks could still leverage Java tools.
• Oracle Enterprise Manager Cloud Control 12c (2011): Released before Oracle Database 12c, this version fully embraced a browser-based interface as the standard. It was built on Oracle WebLogic Server and provided a comprehensive web UI for managing databases, middleware, and other systems. This predates the Oracle Database 12c release.
• Oracle Database 12c Context: When Oracle Database 12c was released in 2013, it included Enterprise Manager Database Express (EM Express), a lightweight, browser-based tool specifically for managing individual Oracle Database 12c instances. EM Express replaced the heavier Java-based Database Control from 11g and earlier, running directly from the database’s XML DB infrastructure via HTTPS. This was a simpler, database-specific tool compared to the full-fledged Enterprise Manager Cloud Control 12c.

Oracle Database 12c did not "introduce" the browser-based Oracle Enterprise Manager in the broader sense, that transition began with Grid Control 10g and was completed with Cloud Control 12c in 2011. However, within the context of database-specific management tools, Oracle Database 12c did introduce EM Express, which was a new, lightweight, browser-based alternative to the Java-based Database Control of earlier database versions like 8i through 11g.
Summary

• The Java-based interface was phased out as the primary interface with Oracle Enterprise Manager Cloud Control 12c (2011).
• Oracle Database 12c (2013) introduced EM Express, a browser-based tool tailored for managing Oracle Database 12c instances, replacing the Java-based Database Control from prior versions (e.g., 8i). However, the broader shift to a browser-based Enterprise Manager predates this with Cloud Control 12c.

The database management tool tied to Oracle Database 12c introduced a browser-based interface with EM Express, but the full Enterprise Manager product had already moved away from Java earlier.

The DBA, can monitor your database activity, run SQL scripts, or even start and stop the database from any location with a Web browser and an Internet connection.
You can enable Web-based access to your Enterprise Manager console in two ways:

1. For a fat client: your remote computer installs the Enterprise Manager client and then uses the Internet connection and a Web browser to reach the Enterprise Manager server.
2. For a thin client: your remote computer has only a Web browser, and the Enterprise Manager console is served from a Web server with access to the Enterprise Manager server. The Web server and the Enterprise Manager server can be on the same machine or on two different machines.

This lesson describes how to set up the latter selection: the thin client. With this configuration, no additional software needs to be installed on the client computer.
A few steps are required to set up the Enterprise Manager console for Web access.
View the following series of images to see how each step works.

A great advantage of running the Enterprise Manager console from the Web is that you have the capability of working with the console from a variety of locations. Many companies use an internal Web server (intranet). This technique would work equally well on either the Internet or the intranet.
The next lesson describes how to prepare for running batch jobs from within the Enterprise Manager console.

[1]Oracle Enterprise Manager Grid Control 10g: Oracle Enterprise Manager Grid Control 10g marked a significant step in the evolution of the OEM user interface by introducing a web-based management console, reducing reliance on Java clients. This version leveraged Oracle Application Server to deliver core functionalities through a browser, making it more accessible. While some administrative tasks still utilized Java tools, 10g laid the groundwork for the fully browser-based interfaces that followed, streamlining the user experience for managing Oracle environments.

[2]: