Programs and Their Execution
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Python |
Java |
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Programs consist of
modules. Modules in turn can
contain statements, function definitions, and/or class definitions. Each module is associated with a
source file (.py extension)
and possibly a byte code file (.pyc extension). An comipler/interpreter called a
Python virtual machine (PVM) translates Python source files to byte code
before execution. The PVM may
save the corresponding byte code in files for subsequent executions.
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Programs consist of
interfaces and classes.
Interfaces and classes are contained in source files (.java extension). A source file compiles into one or more executable byte
code files (.class
extension). Classes and interfaces
can be part of a package. A
package is a bit like a module, from which any resources can be
imported. The byte code files
for a package are usually contained in a directory whose name is the package
name. Programs must first be
compiled before they can be executed.
Programs are either applets or applications. Applets are programs that run in a Web browser. Applications are programs that run on
a standalone computer. In either
case, Java programs execute in an interpreter called a Java virtual machine
(JVM). |