glossary.html

java基础学习

<dt><i>API</i>
<dd>Application Programming Interface. The specification of how a programmer
writing an application accesses the behavior and state of classes and objects.
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<dt><i>applet</i>
<dd>A component that typically executes in a web browser, but can execute in a variety of other applications or devices that support the applet programming model.
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<dt><i>Applet container</i>
<dd>A container that includes support for the applet programming model.
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<dt><i>appliances</i>
<dd>Networked devices such as printers, Java technology-enabled terminals, and clients, that are
managed using applications built with the Java Management API (JMAPI).
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<dt><i>Application Assembler</i>
<dd>A person that combines components and modules into larger deployable application units.
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<dt><i>application client</i>
<dd>A first-tier client program that executes in its own <a href="#jvm">Java Virtual Machine (JVM)</a>.
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<dt><i>application client container</i>
<dd>A container that supports application clients and provides a federated view of the J2EE platform APIs.
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<dt><i>application client module</i>
<dd>A software unit that consists of one or more classes and an application client deployment descriptor.
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<dt><i>Application Component Provider</i>
<dd>A vendor that provides the Java classes that implement components' methods, JSP page definitions, and any required deployment descriptors.
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<dt><i>APM</i>
<dd>Application Programming Model. A programming model that defines how to use and combine the features of the J2EE platform to create solutions for common application domains in the enterprise.
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<dt><i>argument</i>
<dd>A data item specified in a method call. An argument can be a literal value,
a variable, or an expression.
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<dt><i>array</i>
<dd>A collection of data items, all of the same type, in which each item's
position is uniquely designated by an integer.
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<dt><i><a name="ascii">ASCII</a></i>
<dd>American Standard Code for Information Interchange. A standard assignment of
7-bit numeric codes to characters. See also <i><a href="#unicode">Unicode</a></i>.
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<dt><i>atomic</i>
<dd>Refers to an operation that is never interrupted or left in an incomplete
state under any circumstance.
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<dt><i>authentication</i>
<dd>The process by which an entity proves to another entity that it is acting on behalf of a specific identity. The J2EE platform requires three types of authentication: basic, form-based, and mutual.
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<dt><i>authorization</i>
<dd>See <a href="#access control">access control</a>.
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<dt><i>authorization constraint</i>
<dd>A set of security roles that are allowed access to the resources in a web resource collection.
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<dt><i>basic authentication</i>
<dd>When a web server authenticates an entity with a user name and password obtained using the web client's built-in authentication mechanism.
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<dt><i>bean</i>
<dd>A reusable software component. Beans can be combined to create an application.
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<dt><i>bean-managed persistence</i>
<dd>When the transfer of data between an entity bean instance's variables and the underlying resource manager is managed by the entity bean.
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<dt><i>bean-managed transaction</i>
<dd>When an enterprise bean defines the boundaries of the transaction.
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<dt><i>binary operator</i>
<dd>An operator that has two arguments.
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<dt><i>bit</i>
<dd>The smallest unit of information in a computer, with a value of either 0 or 1.
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<dt><i>bitwise operator</i>
<dd>An operator that manipulates the bits of one or more of its operands individually and in parallel.  Examples include the binary logical operators (&amp;, |, ^), the binary shift operators (&lt;&lt;, &gt;&gt;, &gt;&gt;&gt;) and the unary one's complement operator (~).
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<dt><i>block</i>
<dd>In the Java programming language, any code between matching braces.  Example: <code>{ x = 1; }</code>.
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<dt><i>boolean</i>
<dd>Refers to an expression or variable that can have only a true or false value. The Java programming language provides the boolean type and the literal values true and false.
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<dt><i>bounding box</i>
<dd>The smallest rectangle that encloses a geometric shape. For a Raster object, the smallest rectangle that completely encloses all the defined pixels.
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<dt><i>break</i>
<dd>A Java programming language keyword used to resume program execution at the statement immediately following the current statement. If followed by a label, the program resumes execution at the labeled statement.
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<dt><i>business logic</i>
<dd>The code that implements the functionality of an application. In the Enterprise JavaBeans model, this logic is implemented by the methods of an enterprise bean.
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<dt><i>business method</i>
<dd>A method of an enterprise bean that implements the business logic or rules of an application.
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<dt><i>byte</i>
<dd>A sequence of eight bits. The Java programming language provides a corresponding <code>byte</code> type.
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<dt><i>bytecode</i>
<dd>Machine-independent code generated by the Java compiler and executed by the
Java interpreter.
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<dt><i>callback methods</i>
<dd>Methods in a component called by the container to notify the component of important events in its life cycle.
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<dt><i>caller</i>
<dd>Same as caller principal.
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<dt><i>caller principal</i>
<dd>The principal that identifies the invoker of an enterprise bean method.
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<dt><i>case</i>
<dd>A Java programming language keyword that defines a group of statements to begin executing if a value specified matches the value defined by a preceding &quot;switch&quot; keyword.</dd>
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<dt><i>casting</i>
<dd>Explicit conversion from one data type to another.
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<dt><i>catch</i>
<dd>A Java programming language keyword used to declare a block of statements to be executed in the event that a Java exception, or run time error, occurs in a preceding &quot;try&quot; block.</dd>
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<dt><i>char</i>
<dd>A Java programming language keyword used to declare a variable of type character.</dd>
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<dt><i><a name="class">class</a></i>
<dd>In the Java programming language, a type that defines the implementation of a particular kind of object.  A class definition defines instance and class variables and methods, as well as specifying the interfaces the class implements and the immediate superclass of the class.  If the superclass is not explicitly specified, the superclass will implicitly be <code>Object</code>.
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<dt><i><a name="cmethod">class method</a></i>
<dd>A method that is invoked without reference to a particular object. Class methods affect the class as a whole, not a particular instance of the class. Also called a <i><a href="#smethod">static method</a></i>. See also <i><a href="#imethod">instance method</a></i>.
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<dt><i><a name="cvariable">class variable</a></i>
<dd>A data item associated with a particular class as a whole--not with particular instances of the class. Class variables are defined in class definitions. Also called a <i><a href="#sfield">static field</a></i>. See also <i><a href="#ivariable">instance variable</a></i>.
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<dt><i>classpath</i>
<dd>A classpath is an environmental variable which tells the Java<sup><font size="-2">TM</font></sup> virtual machine<a href="#TJVM"><sup>1</sup></a> and Java technology-based applications (for example, the tools located in the JDK 1.1.X\bin directory) where to find the class libraries, including user-defined class libraries.
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<dt><i><a name="client">client</a></i>
<dd>In the client/server model of communications, the client is a process that
remotely accesses resources of a compute server, such as compute power and large memory capacity.
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<dt><i>codebase</i>
<dd>Works together with the <code>code</code> attribute in the
<code>&lt;APPLET&gt;</code> tag to give a complete specification of where to
find the main applet class file: code specifies the name of the file, and
codebase specifies the URL of the directory containing the file.
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<dt><i>comment</i>
<dd>In a program, explanatory text that is ignored by the compiler. In
programs written in the Java programming language, comments are
delimited using <code>//</code> or <code>/*</code>...<code>*/</code>.
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<dt><i>commit</i>
<dd>The point in a transaction when all updates to any resources involved in the transaction are made permanent.
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<dt><i>compilation unit</i>
<dd>The smallest unit of source code that can be compiled. In the current implementation of the Java platform, the compilation unit is a file.
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<dt><i><a name="compiler">compiler</a></i>
<dd>A program to translate source code into code to be executed by a computer.  The Java compiler translates source code written in the Java programming language into bytecode for the Java virtual machine<a href="#TJVM"><sup>1</sup></a>. See also <i><a href="#interpreter">interpreter</a></i>.
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<dt><i>component</i>
<dd>An application-level software unit supported by a container. Components are configurable at deployment time. The J2EE platform defines four types of components: enterprise beans, web components, applets, and application clients.
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<dt><i>component contract</i>
<dd>The contract between a component and its container. The contract includes: life cycle management of the component, a context interface that the instance uses to obtain various information and services from its container, and a list of services that every container must provide for its components.
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<dt><i>component environment</i>
<dd>A set of requirements defined by the Application Component Provider required to be available to a J2EE component in its naming environment. The environment entries are declaratively specified in the component's deployment descriptor. Each component names and accesses its environment configuration values using the java:comp/env JNDI context. These values can be objects a component is dependent on, such as a JDBC DataSource or a simple value such as a tax rate.
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<dt><i>compositing</i>
<dd>The process of superimposing one image on another to create a single image.
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<dt><i>connection</i>
<dd>See <a href="#rmc">resource manager connection</a>.
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<dt><i>connection factory</i>
<dd>See <a href="#rmcf">resource manager connection factory</a>.
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<dt><i>connector</i>
<dd>A standard extension mechanism for containers to provide connectivity to EISs. A connector is specific to an EIS and consists of a resource adapter and application development tools for EIS connectivity. The resource adapter is plugged in to a container through its support for system level contracts defined in the connector architecture.
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<dt><i>connector architecture</i>
<dd>An architecture for integration of J2EE servers with EISs. There are two parts to this architecture: a EIS vendor-provided resource adapter and a J2EE server that allows this resource adapter to plug in. This architecture defines a set of contracts that a resource adapter has to support to plug in to a J2EE server, for example, transactions, security, resource management.
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<dt><i>constructor</i>
<dd>A pseudo-method that creates an object. In the Java programming language, constructors are instance methods with the same name as their class. Constructors are invoked using the <code>new</code> keyword.
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<dt><i>const</i>
<dd>This is a reserved Java programming language keyword. However, it is not used by current versions of the Java programming language.
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<dt><i>container</i>
<dd>An entity that provides life cycle management, security, deployment, and runtime services to components. Each type of container (EJB, Web, JSP, servlet, applet, and application client) also provides component-specific services.
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<dt><i>container-managed persistence</i>
<dd>When transfer of data between an entity bean's variables and the underlying resource manager is managed by the enterprise bean's container.
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