administrative console A graphical interface that guides the user through systems administration tasks such as deployment, configuration, monitoring, starting, and stopping applications, services, and resources.
connection pool A group of host connections that are maintained in an initialized state, ready to be used without having to create and initialize them.
CPU Central Processing Unit. The part of the computer that controls the interpretation and execution of instructions.
CTG CICS® Transaction Gateway. CTG integrates the J2EE Application Server applications of your site with key mature business systems running on CICS servers. CTG integrates middle-tier application servers with CICS by providing a multiuser gateway that supports Web applications written in Java™, C/C++, Visual Basic, and COBOL. CTG supports three programming interfaces: the External Call Interface (ECI), the External Presentation Interface (EPI), and the External Security Interface (ESI). The latest version of CTG implements the J2EE Connector Architecture (JCA), which allows enterprise Java technology to exploit CICS applications.
data sources Data pertaining to JDBC data streams. These are logical connections to database subsystems.
DCE Distributed Computing Environment. A specification from the Open Software Foundation (OSF) that supports remote function execution across a network. J2EE Application Server uses DCE to provide certain types of security, for example, authentication of tokens, tickets, or credentials in an untrusted network.
design patterns Written narratives that define a recurring problem, outline a solution, and describe the tradeoffs involved in implementing that solution. In object-oriented programming environments like Java, a design pattern also describes certain objects and object classes to be used when designing such a solution.
DHCP Dynamic Host Configuration Protocol. A communications protocol that lets network administrators centrally manage the assignment of Internet Protocol (IP) addresses across an organization network. Without DHCP, each computer IP address must be entered manually at each computer; if computers move to another location in another part of the network, a new IP address must be chosen. DHCP lets a network administrator supervise and distribute IP addresses from a central point and automatically sends a new IP address when a computer is plugged into a different location in the network.
dynamic cache A consolidation of several caching activities, including servlets, Web services, and J2EE commands into one service where these activities work together to improve performance and share configuration parameters.
EJB Enterprise Java Bean. A component architecture for the development and deployment of object-oriented, distributed, enterprise-level applications. Applications written using the Enterprise JavaBeans architecture are scalable, transactional, multi-user, and secure.
EJB module A software unit that consists of one or more enterprise beans and an EJB deployment descriptor.
garbage collection A facility of the JVM that reallocates and frees up memory lost when objects are created and later destroyed. Garbage collection usually occurs when insufficient heap space is available for allocating new objects, although you can trigger it manually by invoking the System.gc method.
Garbage collection can be expensive since it involves identifying all the unreferenced objects, removing them from the heap, and then possibly compacting the heap.
heap A memory storage area known formally as the System Resources area that stores system information about running applications. The main storage area used for allocating Java classes and object instances, as well as executable code. The allocation of objects on the heap creates a live or active object. The object exists as long as the JVM maintains a pointer to it; when all references to an object cease to exist, it is subject to garbage collection.
hover help A form of online help that can be viewed by moving a cursor over a GUI item such as an icon or field.
HTTP Hypertext Transfer Protocol. A suite of protocols for the Internet that transfer and display hypertext documents.
HTTP sessions Data related to sessions of specific World Wide Web browsers.
IIOP Internet Inter-ORB Protocol. A protocol that distributed programs written in different programming languages can use to communicate over the Internet. IIOP is a part of the Common Object Request Broker Architecture (CORBA). IIOP is based on the client/server computing model, in which a client program makes requests of a server program that waits to respond to client requests. With IIOP, you can write client programs that communicate with the existing server programs of your site wherever they are located. You can do this without having to understand anything about the server other than the service it performs and its address (called the Interoperable Object Reference, IOR, which comprises the server port number and IP address).
instrumentation The process of modifying program code so that the time it takes the code to run, along with other statistics, can be measured. These modifications insert hooks into these Java methods so that the real time and CPU time spent executing the methods can be measured. Instrumentation is key to certain data-collection features (such as lock analysis) of IBM Tivoli Composite Application Manager for Application Diagnostics Agent for J2EE.
IBM® Tivoli® Monitoring platform The software architecture and foundation that support the development and operations of Tivoli Enterprise Portal and its Tivoli Enterprise Monitoring Agents.
J2EE Java 2 Platform, Enterprise Edition. An environment for developing and deploying enterprise applications using the Java language. The J2EE platform consists of a set of services, application programming interfaces (APIs), and protocols that provide the functions needed for developing multi-tiered, Web-based applications.
JAR file A Java archive file, which is a compressed file containing many class files along with their directory structure.
JavaBean The Java implementation of component-based software architecture, which defines how small, tested software entities called components can be integrated to build complete software solutions (called containers).
JCA J2EE Connector Architecture. A template for writing your own connectors. The template is a binding between a J2EE application server and a backend enterprise information system (EIS) or data repository such as CICS, IMS™, or DB2®.
JDBC Java Database Connectivity. An application programming interface (API) for connecting Java programs to the data in a relational database. With this API, you can encode data requests in Structured Query Language (SQL) that JDBC then passes to the database manager for interpretation and processing.
JMS Java Message Service. A programming interface that connects Java programs to middleware messaging applications, for example, J2EE MQ.
JMX Java Management Extensions. A standard technology for management and monitoring of Java applications and Java environments that defines architecture, application programming interfaces (APIs), and services for application and network management. JMX provides tools for building distributed, Web-based solutions for managing and monitoring Java devices and applications.
A JMX agent is an MBean container.
JNDI Java Naming and Directory Interface. A programming interface that connects Java applications to naming and directory servers such as LDAP.
JSP Java server page. A Web page that specifies one or more servlets whose execution on the Web server modifies the page content or appearance before it is presented to the user.
JTA Java Transaction API. An application programming interface developed by Sun Microsystems that specifies standard Java interfaces between a transaction manager (such as Tuxedo) and other players in a distributed transaction system: the resource manager, the application server, the transactional applications, and often the database manager as well.
JVM Java virtual machine. A software implementation of a central processing unit (CPU) that runs Java applets and applications. The JVM provides a software execution engine that safely and compatibly executes the byte codes in Java class files on various microprocessors, whether embedded in a computer or in another electronic device.
JVMPI Java Virtual Machine Profiling Interface. An experimental interface that provides profiling hooks into the Java virtual machine. This interface supports two-way function calls between the JVM and a profiler agent: the virtual machine notifies the agent of various events, and the agent issues requests for control information.
Kerberos A security system from the Massachusetts Institute of Technology that provides security services for networking.
LDAP Lightweight Directory Access Protocol. A protocol that uses TCP/IP to access directories. Applications can use these directories for storing common data and for retrieving data. For example, applications can use LDAP to access such information as email address, service configuration parameters, or public keys.
lock A semaphore created through the use of the Java synchronized keyword that prevents simultaneous access to a Java object or section of code.
MBeans Managed Beans. A set of standard instrumentation methods for use in Java programs and by Java management applications (such as IBM Tivoli Composite Application Manager for Application Diagnostics Agent for J2EE) that allows monitoring and management of Java-based applications. An MBean is a JavaBean that represents a JMX-manageable resource.
monitor 1) A transaction environment for maintaining large quantities of data in a consistent state and that controls which users and clients can access data through authorized servers. 2) A programming primitive created so multiple program threads can share the same resource (such as an object). A program creates a monitor for a given resource by requesting it from the system; the system returns a unique ID for that monitor. After that, any thread needing the resource must use the monitor to lock the resource while the thread is using it. If the monitor is already locked, a thread requesting the resource is queued by the system and then given control when the monitor becomes unlocked. Also called a mutex.
MVC The Model/View/Controller design pattern is based on the separation of the application into three objects: the user interface ("view"), the logical structure of the data the application requires ("model"), and the user commands that change the view or the model ("controller"). Design patterns themselves are written narratives that define a recurring problem, outline a solution, and describe the tradeoffs involved in implementing that solution (in object-oriented programming environments like Java, a design pattern also describes certain objects and object classes to be used when creating such a solution).
node Any managed system, such as a J2EE application server, that the Tivoli Enterprise Portal is monitoring. A node can also be a managed system of subnodes being managed under a primary node.
OLT Object Level Trace. A tool for testing distributed applications that include a graphical trace facility and a remote debugger.
ORB Object Request Broker. In object-oriented programming, software that serves as an intermediary by transparently enabling objects to exchange requests and responses.
PMI Performance Monitoring Infrastructure. The application programming interface (API) that IBM provides for extracting J2EE Application Server performance data. PMI must be enabled and the appropriate instrumentation levels set for the Tivoli Enterprise Monitoring Agent to extract PMI data and populate certain workspaces. PMI runs as an interface to JMX.
portal A Web-based application that commonly provides personalization, single signon, and content aggregation from different sources, and hosts the presentation layer of Information Systems (IS). Portals are becoming the next-generation desktop, delivering e-business applications over the Web to many types of client devices.
portlet A Java technology-based Web component, managed by a portlet container, that process requests and generates dynamic content. Portlets are used by portals as pluggable user interface components that provide a presentation layer to various heterogeneous Enterprise Information Systems (EIS) or Information Systems (IS).
request The entry point into an application whose processing or response time directly affects the response time the end user perceives. In IBM Tivoli Composite Application Manager for Application Diagnostics Agent for J2EE, a request is a servlet, JSP, or EJB method. Also called a transaction.
request analysis A configuration technique for a request (that is, a transaction) within J2EE Application Server that allows you to see how often the request runs and what factors about the request degrade its performance. Request analysis involves collecting and aggregating request data on each request that runs. Its primary purpose is to report on requests running in the application server, how often they run, their response time, and what is causing performance degradation.
Request analysis works by dynamic object code instrumentation, which modifies the Java object code for the application' s classes as they are being loaded into the JVM.
resource adapter An implementation of the J2EE Connector Architecture Specification that provides applications with access to resources outside of the server or provides server applications with access to an Enterprise Information System (EIS). A resource adapter can provide applications access to resources such as DB2, CICS, SAP, and PeopleSoft. It can provide an EIS with the ability to communicate with message-driven beans configured on the server. A resource adapter is implemented in a resource adapter archive file, which has an extension of .rar. A resource adapter can be provided as a stand-alone adapter or as part of an application, in which case it is referred to as an embedded adapter.
RMI Remote Method Invocation. A Java standard from Sun Microsystems that performs a remote procedure call (RPC) to allow Java objects stored in the network to be accessed remotely in a client/server environment.
RPC Remote Procedure Call. A protocol based on the Distributed Computing Environment (DCE) of the Open Software Foundation. DCE allows one program to request services from a program running on another computer in a network. (A procedure call is also known as a function call or a subroutine call.) RPC uses the client/server model: the requesting program is the client, and the responding program is the server. As with a local procedure call, an RPC is a synchronous operation: the requesting program is suspended until the remote procedure returns its results.
servlet A Java application that runs in an application server or Web server, and that provides server-side processing.
session A series of requests to a servlet that originate from the same user at the same browser. Sessions allow applications running in a Web container to track individual users.
signature The name of an operation or method and its parameters.
SSL Secure Sockets Layer. A security protocol for communication privacy to provide secure client-server conversations.
struts A widely used framework for developing servlet- or JSP-based Web applications that is distributed as open source by the Apache Jakarta Project. Struts encourages application architectures based on the Model two approach, a variation of the Model-View-Controller (MVC) design paradigm.
thread A dispatchable unit of work.
thread pool The threads that are being used by or are available to a computer program.
transaction A single execution of a workload.
URI Uniform Resource Identifier. An identifier for a point of content on the Internet, be it a page of text, a video or sound clip, a still or animated image, or a program. The most common form of URI is the Web page address, which is a particular form of URI called a Universal Resource Locator (URL). A URI typically describes the mechanism used to access the resource, the computer that houses the resource, and the name of the resource (such as a file name) on that computer.
URL Universal Resource Locator. The unique address for a file accessible via the Internet. Such a file might be a Web page (usually the home page), an image file, or a program such as a Java applet or servlet. The URL comprises the protocol used to access the file, a domain name that identifies a specific computer on the Internet, and a path name that specifies that file location on that computer.
Web applications The runtime environment for dynamic Web applications. A J2EE Web application server implements the services of the J2EE standard. It provides communications, resource management, security, transaction management, and persistence capabilities for Web applications. It also typically includes an administration interface for managing the server and deployed applications.
Web container A special J2EE container that manages Web applications in a J2EE architecture. A Web container specifies a runtime environment for Web components, including security, concurrency, life cycle management, transaction, deployment, and other services; it also enables a Web application to access external resources such as relational databases (via JDBC) and Enterprise Java Beans. A Web container provides the same services as a JSP container and provides support for managing Java Server Pages.
Every J2EE server contains at least one Web container.