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55-585: Tomcat is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation, released under the Apache License 2.0 license. Tomcat 4.x was released with Catalina (a servlet container), Coyote (an HTTP connector) and Jasper (a JSP engine ). Catalina is Tomcat's servlet container . Catalina implements Sun Microsystems ' specifications for servlet and JavaServer Pages (JSP). In Tomcat,

110-485: A Realm element represents a "database" of usernames, passwords, and roles (similar to Unix groups) assigned to those users. Different implementations of Realm allow Catalina to be integrated into environments where such authentication information is already being created and maintained, and then use that information to implement Container Managed Security as described in the Servlet Specification. Coyote

165-412: A deadline. Software analysis begins with a requirements analysis to capture the business needs of the software. Challenges for the identification of needs are that current or potential users may have different and incompatible needs, may not understand their own needs, and change their needs during the process of software development. Ultimately, the result of analysis is a detailed specification for

220-576: A longer interval (perhaps minutes, or even never) for a deployed Web application . According to Joel Murach and Michael Urban, authors of the book "Murach's Java Servlets and JSP", embedding Java code in JSP is generally bad practice. A better approach would be to migrate the back-end logic embedded in the JSP to the Java code in the Servlet . In this scenario, the Servlet is responsible for processing, and

275-420: A note to his site saying that JSP had improved since 2000, but also cited its competitors, Apache Velocity and Tea (template language). Today, several alternatives and a number of JSP-oriented pages in larger web apps are considered to be technical debt. Software developer Software development is the process of designing and implementing a software solution to satisfy a user . The process

330-526: Is a Connector component for Tomcat that supports the HTTP 1.1 and 2 protocol as a web server. This allows Catalina, nominally a Java Servlet or JSP container, to also act as a plain web server that serves local files as HTTP documents. Coyote listens for incoming connections to the server on a specific TCP port and forwards the request to the Tomcat Engine to process the request and send back a response to

385-443: Is a fragment of Java code that runs when the user requests the page. Other common delimiters include <%= ... %> for expressions, where the scriptlet and delimiters are replaced with the result of evaluating the expression, and directives , denoted with <%@ ... %> . Java code is not required to be complete or self-contained within a single scriptlet block. It can straddle markup content, provided that

440-511: Is a framework that provides the viewpoints on the system and its environment , to be used in the software development process . It is a graphical representation of the underlying semantics of a view. The purpose of viewpoints and views is to enable human engineers to comprehend very complex systems and to organize the elements of the problem around domains of expertise . In the engineering of physically intensive systems, viewpoints often correspond to capabilities and responsibilities within

495-408: Is a popular way of managing changes made to the software. Whenever a new version is checked in, the software saves a backup of all modified files. If multiple programmers are working on the software simultaneously, it manages the merging of their code changes. The software highlights cases where there is a conflict between two sets of changes and allows programmers to fix the conflict. A view model

550-572: Is an implementation of the Sun Microsystems' JSP 2.0 specification. From Jasper to Jasper 2, important features were added: Three new components were added with the release of Tomcat 7: This component has been added to manage large applications. It is used for load balancing that can be achieved through many techniques. Clustering support currently requires the JDK version 1.5 or higher. A high-availability feature has been added to facilitate

605-451: Is compiled and executed on the server to deliver a document. The compiled pages, as well as any dependent Java libraries, contain Java bytecode rather than machine code . Like any other .jar or Java program, code must be executed within a Java virtual machine (JVM) that interacts with the server's host operating system to provide an abstract, platform-neutral environment. JSPs are usually used to deliver HTML and XML documents, but through

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660-449: Is correctly incorporated with the newer software. Design involves choices about the implementation of the software, such as which programming languages and database software to use, or how the hardware and network communications will be organized. Design may be iterative with users consulted about their needs in a process of trial and error . Design often involves people expert in aspect such as database design , screen architecture, and

715-833: Is essential to success. This is more easily achieved if the team is small, used to working together, and located near each other. Communications also help identify problems at an earlier state of development and avoid duplicated effort. Many development projects avoid the risk of losing essential knowledge held by only one employee by ensuring that multiple workers are familiar with each component. Software development involves professionals from various fields, not just software programmers but also individuals specialized in testing, documentation writing, graphic design , user support, marketing , and fundraising. Although workers for proprietary software are paid, most contributors to open-source software are volunteers. Alternately, they may be paid by companies whose business model does not involve selling

770-399: Is helpful for new developers to understand the project when they begin working on it. In agile development, the documentation is often written at the same time as the code. User documentation is more frequently written by technical writers . Accurate estimation is crucial at the feasibility stage and in delivering the product on time and within budget. The process of generating estimations

825-422: Is inefficient, difficult to understand, or lacking documentation on its functionality. These standards are especially likely to break down in the presence of deadlines. As a result, testing, debugging, and revising the code becomes much more difficult. Code refactoring , for example adding more comments to the code, is a solution to improve the understandability of code. Testing is the process of ensuring that

880-744: Is more encompassing than programming , writing code , in that it includes conceiving the goal, evaluating feasibility, analyzing requirements , design , testing and release . The process is part of software engineering which also includes organizational management , project management , configuration management and other aspects. Software development involves many skills and job specializations including programming , testing , documentation , graphic design , user support , marketing , and fundraising . Software development involves many tools including: compiler , integrated development environment (IDE), version control , computer-aided software engineering , and word processor . The details of

935-440: Is often delegated by the project manager . Because the effort estimation is directly related to the size of the complete application, it is strongly influenced by addition of features in the requirements—the more requirements, the higher the development cost. Aspects not related to functionality, such as the experience of the software developers and code reusability, are also essential to consider in estimation. As of 2019 , most of

990-432: Is often used to break down the customer's requirements into pieces that can be implemented by software programmers. The underlying logic of the program may be represented in data-flow diagrams , data dictionaries , pseudocode , state transition diagrams , and/or entity relationship diagrams . If the project incorporates a piece of legacy software that has not been modeled, this software may be modeled to help ensure it

1045-401: Is robust to heavy levels of input or usage), integration testing (to ensure that the software is adequately integrated with other software), and compatibility testing (measuring the software's performance across different operating systems or browsers). When tests are written before the code, this is called test-driven development . Production is the phase in which software is deployed to

1100-474: Is similar to PHP and ASP , but uses the Java programming language . To deploy and run Jakarta Server Pages, a compatible web server with a servlet container , such as Apache Tomcat or Jetty , is required. Architecturally, JSP may be viewed as a high-level abstraction of Jakarta Servlets . JSPs are translated into servlets at runtime, therefore JSP is a Servlet; each JSP servlet is cached and re-used until

1155-680: Is the JSTL . Jakarta Standard Tag Library (JSTL) supports common tasks that must be performed in JSPs. Examples includes iteration and conditionals (the equivalent of "for" and "if" statements in Java). Out of all the libraries in JSTL, the JSTL core library is most commonly used. A taglib directive must be used to specify the URI of the JSTL core library using a prefix. Although there are many different choices for

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1210-431: Is then written between the opening and closing braces. The following is an example of EL syntax : The value of variable in the object javabean is $ {javabean.variable} . The JSP syntax add additional tags, called JSP actions, to invoke built-in functionality. Additionally, the technology allows for the creation of custom JSP tag libraries that act as extensions to the standard JSP syntax. One such library

1265-471: Is used to set the properties for a bean. For the getProperty and setProperty tags, the name attribute is used to specify the bean's name. So the name attribute must match the id attribute provided by the useBean tag. Version 2.0 of the JSP specification added support for the Expression Language (EL), used to access data and functions in Java objects. In JSP 2.1, it was folded into

1320-424: The useBean tag looks similar to an HTML tag, all JSP tags for JavaBeans use XML syntax. Therefore the code containing the useBean tag is case-sensitive. The useBean tag contains several attributes. The id attribute declares the name that is used for gaining access to the bean. The class attribute declares the package and class for the bean. The scope declares the object responsible for storing

1375-553: The Unified Expression Language , which is also used in JavaServer Faces . The JSP Expression Language uses a compact syntax which enables the developer to get attributes and JavaBean properties from a given request object. When using EL, a dollar sign ("$ ") must be added at the beginning of the code. The dollar symbol is followed by an opening brace ("{"), as well as a closing brace ("}"). The code

1430-471: The programming language ). Documentation comes in two forms that are usually kept separate—that intended for software developers, and that made available to the end user to help them use the software. Most developer documentation is in the form of code comments for each file, class , and method that cover the application programming interface (API)—how the piece of software can be accessed by another—and often implementation details. This documentation

1485-555: The JSP is responsible for displaying the HTML, maintaining a clear separation of concerns . In 2000, Jason Hunter, author of "Java Servlet Programming" described a number of "problems" with JavaServer Pages. Nevertheless, he wrote that while JSP may not be the "best solution for the Java Platform" it was the "Java solution that is most like the non-Java solution," by which he meant Microsoft's Active Server Pages . Later, he added

1540-486: The Servlet 6.0 and JSP 3.1 Specifications. Tomcat 11.x implements the Servlet 6.1 and JSP 4.0 Specifications. Tomcat started off as a servlet reference implementation by James Duncan Davidson , a software architect at Sun Microsystems. He later helped make the project open-source and played a key role in its donation by Sun Microsystems to the Apache Software Foundation. The Apache Ant software build automation tool

1595-489: The available methodologies are best suited to specific kinds of projects, based on various technical, organizational, project, and team considerations. Another focus in many programming methodologies is the idea of trying to catch issues such as security vulnerabilities and bugs as early as possible ( shift-left testing ) to reduce the cost of tracking and fixing them. In 2009, it was estimated that 32 percent of software projects were delivered on time and budget, and with

1650-449: The bean. The value for the scope defines the duration for which the bean is available for the rest of the java application to use. The scope can be one of the following four values: After a bean has been created using the useBean tag, the getProperty and setProperty tags can be used for getting and setting the properties of the bean. The JSP getProperty is used to get the property of created bean. The JSP setProperty tag

1705-423: The code executes correctly and without errors. Debugging is performed by each software developer on their own code to confirm that the code does what it is intended to. In particular, it is crucial that the software executes on all inputs, even if the result is incorrect. Code reviews by other developers are often used to scrutinize new code added to the project, and according to some estimates dramatically reduce

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1760-442: The common <%@ page .. %> directive may instead be written as a <jsp:directive.page .. /> tag, and tag libraries are imported using XML namespaces , instead of the usual <%@ taglib .. %> tag. A JavaServer Pages compiler is a program that parses JSPs and transforms them into executable Java Servlets . A program of this type is usually embedded into the application server and run automatically

1815-408: The end user. During production, the developer may create technical support resources for users or a process for fixing bugs and errors that were not caught earlier. There might also be a return to earlier development phases if user needs changed or were misunderstood. Software development is performed by software developers , usually working on a team. Efficient communications between team members

1870-430: The engineering organization. Fitness functions are automated and objective tests to ensure that the new developments don't deviate from the established constraints, checks and compliance controls. Intellectual property can be an issue when developers integrate open-source code or libraries into a proprietary product, because most open-source licenses used for software require that modifications be released under

1925-401: The first time a JSP is accessed, but pages may also be precompiled for better performance, or compiled as a part of the build process to test for errors. Some JSP containers support configuring how often the container checks JSP file timestamps to see whether the page has changed. Typically, this timestamp would be set to a short interval (perhaps seconds) during software development , and

1980-477: The full functionality. An additional 44 percent were delivered, but missing at least one of these features. The remaining 24 percent were cancelled prior to release. Software development life cycle refers to the systematic process of developing applications . The sources of ideas for software products are plentiful. These ideas can come from market research including the demographics of potential new customers, existing customers, sales prospects who rejected

2035-407: The number of bugs persisting after testing is complete. Once the code has been submitted, quality assurance —a separate department of non-programmers for most large companies—test the accuracy of the entire software product. Acceptance tests derived from the original software requirements are a popular tool for this. Quality testing also often includes stress and load checking (whether the software

2090-450: The original JSP is modified. Jakarta Server Pages can be used independently or as the view component of a server-side model–view–controller design, normally with JavaBeans as the model and Java servlets (or a framework such as Apache Struts ) as the controller. This is a type of Model 2 architecture. JSP allows Java code and certain predefined actions to be interleaved with static web markup content, such as HTML. The resulting page

2145-401: The output when the if condition evaluates to true. Likewise, content inside a loop construct may appear multiple times in the output, depending upon how many times the loop body runs. The following would be a valid for loop in a JSP page: The output displayed in the user's web browser would be: The JSP useBean tag enables the developer to access and create a Javabean. Although using

2200-439: The page as a whole is syntactically correct. For example, any Java if/for/while blocks opened in one scriptlet must be correctly closed in a later scriptlet for the page to successfully compile. This allows code to be intermingled and can result in poor programming practices. Content that falls inside a split block of Java code (spanning multiple scriptlets) is subject to that code. Content inside an if block will only appear in

2255-403: The performance of servers and other hardware. Designers often attempt to find patterns in the software's functionality to spin off distinct modules that can be reused with object-oriented programming . An example of this is the model–view–controller , an interface between a graphical user interface and the backend . The central feature of software development is creating and understanding

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2310-456: The prefix, the "c" prefix is commonly used for this library. JSP pages may also be written in fully valid XML syntax. Such JSP files commonly use the alternative .jspx file extension, which usually causes the application server to validate the XML syntax. Since the usual JSP syntax <% ... %> is not valid in XML, a developer must use alternative tags provided by JSP. For example,

2365-463: The process used for a development effort varies. The process may be confined to a formal, documented standard , or it can be customized and emergent for the development effort. The process may be sequential, in which each major phase (i.e. design, implement and test) is completed before the next begins, but an iterative approach – where small aspects are separately designed, implemented and tested – can reduce risk and cost and increase quality. Each of

2420-424: The product that developers can work from. Software analysts often decompose the project into smaller objects, components that can be reused for increased cost-effectiveness, efficiency, and reliability. Decomposing the project may enable a multi-threaded implementation that runs significantly faster on multiprocessor computers. During the analysis and design phases of software development, structured analysis

2475-466: The product, other internal software development staff, or a creative third party. Ideas for software products are usually first evaluated by marketing personnel for economic feasibility, fit with existing channels of distribution, possible effects on existing product lines, required features , and fit with the company's marketing objectives. In the marketing evaluation phase, the cost and time assumptions become evaluated. The feasibility analysis estimates

2530-518: The project obtained certification by Oracle Corporation as a compatible implementation of the Java EE 6 Web Profile. Related software that is now obsolete or defunct: JSP engine Jakarta Server Pages ( JSP ; formerly JavaServer Pages ) is a collection of technologies that helps software developers create dynamically generated web pages based on HTML , XML , SOAP , or other document types. Released in 1999 by Sun Microsystems , JSP

2585-503: The project's return on investment , its development cost and timeframe. Based on this analysis, the company can make a business decision to invest in further development. After deciding to develop the software, the company is focused on delivering the product at or below the estimated cost and time, and with a high standard of quality (i.e., lack of bugs) and the desired functionality. Nevertheless, most software projects run late and sometimes compromises are made in features or quality to meet

2640-529: The requesting client. Another Coyote Connector, Coyote JK, listens similarly but instead forwards its requests to another web server, such as Apache, using the JK Protocol . This usually offers better performance. Jasper is Tomcat's JSP Engine. Jasper parses JSP files to compile them into Java code as servlets (that can be handled by Catalina). At runtime, Jasper detects changes to JSP files and recompiles them. As of version 5, Tomcat uses Jasper 2, which

2695-427: The scheduling of system upgrades (e.g. new releases, change requests) without affecting the live environment. This is done by dispatching live traffic requests to a temporary server on a different port while the main server is upgraded on the main port. It is very useful in handling user requests on high-traffic web applications. Tomcat 9.x implements the Servlet 4.0 and JSP 2.3 Specifications. Tomcat 10.1.x implements

2750-427: The software that implements the desired functionality. There are various strategies for writing the code. Cohesive software has various components that are independent from each other. Coupling is the interrelation of different software components, which is viewed as undesirable because it increases the difficulty of maintenance . Often, software programmers do not follow industry best practices, resulting in code that

2805-403: The software, but something else—such as services and modifications to open source software. Computer-aided software engineering (CASE) is tools for the partial automation of software development. CASE enables designers to sketch out the logic of a program, whether one to be written, or an already existing one to help integrate it with new code or reverse engineer it (for example, to change

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2860-544: The tomcat was already in use for another O'Reilly title, his wish to see an animal cover eventually came true when O'Reilly published their Tomcat book with a snow leopard on the cover in 2003. Apache TomEE (pronounced "Tommy") is the Enterprise Edition of Apache Tomcat (Tomcat + Java/Jakarta EE = TomEE) that combines several Java enterprise projects including Apache OpenEJB , Apache OpenWebBeans , Apache OpenJPA , Apache MyFaces and others. In October 2011,

2915-520: The tools for estimating the amount of time and resources for software development were designed for conventional applications and are not applicable to web applications or mobile applications . An integrated development environment (IDE) supports software development with enhanced features compared to a simple text editor . IDEs often include automated compiling , syntax highlighting of errors, debugging assistance, integration with version control , and semi-automation of tests. Version control

2970-421: The use of OutputStream, they can deliver other types of data as well. The Web container creates JSP implicit objects like request, response, session, application, config, page, pageContext, out and exception. JSP Engine creates these objects during translation phase. JSPs use several delimiters for scripting functions. The most basic is <% ... %> , which encloses a JSP scriptlet. A scriptlet

3025-432: Was developed as a side-effect of the creation of Tomcat as an open source project. Davidson had initially hoped that the project would become open-sourced and, since many open-source projects had O'Reilly books associated with them featuring an animal on the cover, he wanted to name the project after an animal. He came up with Tom cat since he reasoned the animal represented something that could fend for itself. Although

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