IBM Tivoli Composite Application Manager for Application Diagnostics, Version 7.1.0.1

Glossary - J2EE agent

class file

A file containing Java object code for a single Java class of objects.

class loader

A Java component that loads Java object classes into the heap.

CGI

Common Gateway Interface. The standard way for a Web server to pass a Web user's request to an application program and to receive data back to forward to the user. When the user supplies information on a Web page, it usually needs to be processed by an application program. The Web server typically passes the form information to a small application program that processes the data and may send back a confirmation message. This method or convention for passing data back and forth between the server and the application is called the Common Gateway Interface (CGI). It is part of the Web's Hypertext Transfer Protocol (HTTP).

component

In object-oriented programming environments like Java, a component is a reusable program building block that can be combined with other components running on the same or different computers in a distributed network to form an application. Examples of a component include a single button in a graphical user interface, an interface to a database manager, and an EJB. A component runs within a container.

container

In the Enterprise JavaBeans (EJB) architecture, a container is an application program that executes the program building block known as a component (that is, a JavaBean). You write a Java container (such as a GUI button or a database requester) that runs both prewritten and site-developed JavaBeans. Examples of containers include pages on a Web site as well as the Web browsers themselves.

CPU

Central Processing Unit. The part of the computer that interprets and executes instructions.

CTG

CICS Transaction Gateway. CTG integrates your site's J2EE Application Server applications 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 and other languages, including C/C++, Visual Basic, and COBOL. The Gateway process communicates with CICS applications after receiving requests from:

  • Java programs such as applets and servlets.

  • Special Java classes such as the class JavaGateway, which establishes communication with the CTG process.

  • Native code that handles the communication from the Gateway daemon to the CICS server.

CTG supports these programming interfaces:

  • the External Call Interface (ECI), used when calling COMMAREA-based CICS applications

  • the External Presentation Interface (EPI), used for communicating with 3270-based transactions

  • the External Security Interface (ESI), used for exchanging userid/password information with CICS

The latest version of CTG implements the J2EE Connector Architecture (JCA), which allows enterprise Java technology to exploit CICS applications.

datasources

Data pertaining to J2EE data sources, which 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.

delay

A measurable factor that contributes to the response time of a workload (or transaction), for example, connecting to a JDBC database, reading a row from an SQL database, committing a transaction, or calling a user-defined method. Workloads themselves can be delays to other workloads, for example, a servlet invoking an EJB method.

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 architecting 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's network. Without DHCP, each computer's IP address must be entered manually at each computer and, 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 network location.

EJB

Enterprise JavaBean. A component-based application programming interface that implements component architecture for multitier client/server systems written in Java. See also JavaBean and container.

garbage collection

A facility of the JVM that deallocates 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 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, which 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.

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, a part of the Common Object Request Broker Architecture (CORBA), is based on the client/server computing model, in which a client program makes requests of a server program that waits to respond to a client's requests. With IIOP, you can write client programs that communicate with your site's existing server programs wherever they are located and 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's port number and IP address).

instrumentation

The process of modifying program code so 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 ITCAM for J2EE monitoring agent's workload analysis feature.

J2C

J2EE Application Server's implementation of the connection-management and pool-management components of JCA. Applications needing a backend resource reference a connection factory suitable for use with that resource; the connection factory in turn calls J2EE Application Server's DB2 Relational Resource Adapter, DB2 RRA (which, despite its name, also supports Oracle, SQL Server, and other database management systems). The DB2 RRA passes the connection request to a J2C connection manager, which tries to provide an available connection from a predefined pool. But when all connections are in use, the J2C connection manager calls back to the DB2 RRA to obtain a new connection from the backend system; once this connection is returned, the connection manager adds it to the connection pool for future reuse.

J2C container

The third type of container within J2EE Application Server (EJB containers and Web containers are the other two types). A J2C container contains connection factories that represent backend resources; it also manages access to these resources through a connection manager associated with each connection factory.

J2EE

Java 2 Platform, Enterprise Edition. An environment for developing and deploying multitier enterprise applications. J2EE simplifies development of enterprise applications by basing them on standard, modular components; it comprises a set of services, application programming interfaces (APIs), and protocols that provide the necessary functions for developing multitiered, Web-based applications.

JAR file

A Java archive file, which is a ZIP 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, which is a binding between a J2EE application server and a backend enterprise information system (EIS) or data repository such as 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.

JMS summary data

Data regarding the use of J2EE MQ by J2EE Application Server applications.

JMX

Java Management Extensions. A standard technology for management and monitoring that defines architecture, application programming interfaces (APIs), and services for application and network management in Java. 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. An application programming interface (API) 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's 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.

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 directory databases where applications can store and retrieve common naming and location data. For example, applications can use LDAP to access such information as email addresses, service configuration parameters, and 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.

longest-running workloads

Data related to individual transactions (executions of a workload) that exceed user-defined response-time criteria.

MBeans

Managed Beans. A set of standard instrumentation methods for use in Java programs and by Java management applications like ITCAM for J2EE monitoring agent 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 that 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 an 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”).

node

Any managed system, such as a J2EE server, that Tivoli Enterprise Portal is monitoring. A node can also be a managed system of subnodes, all of which are being managed as components of the primary node.

OLT

Object Level Trace. A tool for testing distributed applications that includes a graphical trace facility and a remote debugger.

PMI

Performance Monitoring Infrastructure. The application programming interface (API) that IBM provides for extracting J2EE Application Server performance data on UNIX and Windows platforms. PMI must be enabled and the appropriate instrumentation levels set for the OMEGAMON XE agent to extract PMI data and populate certain workspaces.

Under J2EE Application Server V5.0, PMI runs as an interface to JMX.

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 Open Software Foundation's Distributed Computing Environment (DCE) that 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.

signature

The name of an operation or method and its parameters.

SSL

Secure Sockets Layer. A security protocol for communication privacy that provides 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 2 approach, a variation of the Model/View/Controller (MVC) design paradigm.

thread

A dispatchable unit of work.

TMS

Tivoli Monitoring Services. The software foundation that supports the development and operations of Tivoli Enterprise Portal (), the Tivoli Enterprise Monitoring Server (monitoring server), and its Tivoli Enterprise Monitoring Agents (monitoring agents).

transaction

A single execution of a workload.

URL

Universal Resource Locator. The unique address for a file that is accessible on the Internet. A common way to get to a Web site is to enter the URL of its home page in your Web browser's address line. However, any file within that Web site can also be specified as the URL. Such a file might be any Web (HTML) page other than the home page, an image file, or a program such as a Common Gateway Interface application or Java applet. The URL contains the name of the protocol used to process the file, a domain name that identifies the specific computer on the Internet, and a pathname to the file on that computer.

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 (through 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.

workload

The entry point into an application whose processing or response time directly affects the response time the end user perceives. In ITCAM for J2EE monitoring agent, the workload is a servlet, JSP, or EJB method. Sometimes called a transaction. See also delay.


Parent topic:

Agent for J2EE Monitoring Agent Installation Guide

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