Java Program Execution

Java Program Execution
The Java byte-code compiler translates a Java source file into machineindependent
byte code. The byte code for each publicly visible class is placed in a
separate file, so that the Java runtime system can easily find it. If your program
instantiates an object of class A, for example, the class loader searches the
directories listed in your CLASSPATH environment variable for a file called A.class
that contains the class definition and byte code for class A.

There is no link phase for Java programs; all linking is done dynamically at The following diagram shows an example of the Java compilation and execution
sequence for a source file named A.java containing public class A and non-public
class B:

Java programs are, in effect, distributed applications. You may think of them as a
collection of DLLs (dynamically loadable libraries) that are linked on demand at
runtime. When you write your own Java applications, you will often integrate
your program with already-existing portions of code that reside on other
machines.