This article is about the argument on the command line of Java programs. For the Free Software Foundation's implementation of the Java standard library, see GNU Classpath. The Classpath is an argument set on the command-line that tells the Java Virtual Machine where to look for user-defined classes and packages in Java programs. The Java Class Library is a set of dynamically loadable libraries that Java applications can call at runtime. ...
GNU Classpath is a project aiming to create a free implementation of the standard class library for the Java programming language. ...
This article or section does not adequately cite its references or sources. ...
A Java Virtual Machine (JVM) is a set of computer software programs and data structures which implements a specific virtual machine model. ...
In object-oriented programming, a class is a programming language construct that is used to group related instance variables and methods. ...
A Java package is a Java programming language mechanism for organizing classes into namespaces. ...
“Java language†redirects here. ...
Overview and Architecture
- See also: Java Classloader
Contrary to the classic dynamic loading behavior, when executing Java programs, the Java Virtual Machine finds and loads classes lazily (the bytecode of a class is loaded only when this class is first used). The virtual machine searches and loads classes in this order: The Java Classloader is a part of the Java Runtime Environment that dynamically loads Java classes into the Java Virtual Machine. ...
Illustration of an application which may use libvorbisfile. ...
“Java language†redirects here. ...
A Java Virtual Machine (JVM) is a set of computer software programs and data structures which implements a specific virtual machine model. ...
Java bytecode is the form of instructions that the Java virtual machine executes. ...
- Bootstrap classes: the classes that are fundamental to the Java Platform (comprising the public classes of the Java Class Library, and the private classes that are necessary for this library to be functional).
- Extension classes: packages that are in the extension directory of the JRE or JDK.
- User-defined packages and libraries
By default only the packages of the JDK standard API, and extension packages are accessible without needing to set where to find them. The path for all user-defined packages and libraries must be set in the command-line (or in the Manifest associated with the Jar file containing the classes). The Java platform is the name for a bundle of related programs, or platform, from Sun Microsystems which allow for developing and running programs written in the Java programming language. ...
The Java Class Library is a set of dynamically loadable libraries that Java applications can call at runtime. ...
A Java package is a Java programming language mechanism for organizing classes into namespaces. ...
JRE can mean Java programming language Justin Reese This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...
The Java Development Kit (JDK) is a Sun product aimed at Java developers. ...
A Java package is a Java programming language mechanism for organizing classes into namespaces. ...
A Java package is a Java programming language mechanism for organizing classes into namespaces. ...
The Java Development Kit (JDK) is a Sun product aimed at Java developers. ...
Java Platform, Standard Edition or Java SE (formerly known up to version 5. ...
A Java package is a Java programming language mechanism for organizing classes into namespaces. ...
Wikipedia does not have an article with this exact name. ...
In computing, a JAR file (or Java ARchive) file used to distribute a set of Java classes. ...
Setting the path to execute Java programs
Basic usage Suppose we have a package structure called org.mypackage containing the following classes : HelloWorld (main class), SupportClass, and UtilClass, the package being physically under the directory D:myprogram (on Windows). Windows redirects here. ...
The corresponding physical file structure is :
D:myprogram | ---> org | ---> mypackage | ---> HelloWorld.class ---> SupportClass.class ---> UtilClass.class To launch the program, we should use the following command : java -classpath D:myprogram org.mypackage.HelloWorld where : - -classpath D:myprogram set the path to the packages used in the program
- org.mypackage.HelloWorld is the path of the main class
Setting the path through an environment variable The Environment variable named CLASSPATH may be alternatively used to set the Classpath. For the above example, we could also use on Windows : Environment variables are a set of dynamic values that can affect the way running processes will behave on a computer. ...
set CLASSPATH=D:myprogram java org.mypackage.HelloWorld
Setting the path of a Jar file Now, suppose the program uses a supporting library enclosed in a Jar file called supportLib.jar, physically in the directory D:myprogramlib. In computing, a JAR file (or Java ARchive) file used to distribute a set of Java classes. ...
The corresponding physical file structure is :
D:myprogram | ---> lib | | | ---> supportLib.jar | ---> org | ---> mypackage | ---> HelloWorld.class ---> SupportClass.class ---> UtilClass.class We should use the following command-line option : java -classpath D:myprogram;D:myprogramlibsupportLib.jar org.mypackage.HelloWorld or alternatively : set CLASSPATH=D:myprogram;D:myprogramlibsupportLib.jar java org.mypackage.HelloWorld
Setting the path in a Manifest file Suppose that our program has been enclosed in a Jar file called helloWorld.jar, put directly in the D:myprogram directory. We have the following file structure: In computing, a JAR file (or Java ARchive) file used to distribute a set of Java classes. ...
D:myprogram | ---> helloWorld.jar | ---> lib | ---> supportLib.jar The manifest file defined in this Jar file has this definition: Wikipedia does not have an article with this exact name. ...
In computing, a JAR file (or Java ARchive) file used to distribute a set of Java classes. ...
Main-Class: org.mypackage.HelloWorld Class-Path: lib/supportLib.jar Note: It's important that the manifest file ends with either a new line or carriage return. Wikipedia does not have an article with this exact name. ...
To launch the program, we can use the following command:
java -jar D:myprogramhelloWorld.jar It is not necessary to define the Main class, the Classpath to the program classes, and the support library classes, because they are already defined in the manifest file. Wikipedia does not have an article with this exact name. ...
The syntax for specifying multiple library JAR files in the manifest file is to separate the entries with a space: Wikipedia does not have an article with this exact name. ...
Class-Path: lib/supportLib.jar lib/supportLib2.jar
OS specific notes Being closely associated with the file system, the command-line Classpath syntax depends on the operating system. For example : - on Windows, the directory structure has a Windows syntax, and each filepath must be separated by a semicolon (";").
- on Linux, Mac OS X, and more generally on all Unix-like operating systems, the directory structure has a Unix syntax, and each filepath must be separated by a colon (":").
This does not apply when the Classpath is defined in Manifest files, where each filepath must be separated by a space (" "), regardless of the operating system. Windows redirects here. ...
Windows redirects here. ...
A semicolon ( ; ) is a punctuation mark. ...
This article is about operating systems that use the Linux kernel. ...
Mac OS X (IPA: ) is a line of graphical operating systems developed, marketed, and sold by Apple Inc. ...
Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ...
Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ...
The colon (:) is a punctuation mark, visually consisting of two equally sized dots centered on the same vertical line. ...
Wikipedia does not have an article with this exact name. ...
See also A Java package is a Java programming language mechanism for organizing classes into namespaces. ...
In computing, a JAR file (or Java ARchive) file used to distribute a set of Java classes. ...
“Java language†redirects here. ...
References
External links - note explaining how Java classes are found, on Sun website
- specification of how to set the Classpath on Sun site
- tutorial on using Classpath for compiling Java programs
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