??????????. ?????.

???????????????? ???????????? java ???????????ó????????????????????????? java ????(?????? native code). ????????????????????????Щ?????. ??????????????????????? ?????? CLASSPATH ????????????????????? ????????? ????????????У? ??????????????????? ????????????????飬 ?Щ??????????????? ???磬 JavaServlet?? Java3D ???. ??????????飬 ??????????????? ????? JARPATH?? ?????????? ?????????? jar zip????? ?????? SUN ?????????.  windows98 ?￡? ????????????? ???????? ?????????? ?ò??????????? ??????????????????? ???? tool.jar ???? CLASSPATH ????????. ????????????????????????. ??????β???? ??????????????? jdk ??????? ?????????????????????? ??????ο?????. ??????????????? ?????????????? ??tools.jar ???? CLASSPATH?? ?????.

???????? ?? (package)

????Java ?е? "??" ???????????????? package ???????????:Definition: A package is a collection of related classes and interfaces that provides access protection and namespace management.    ???: ????????Щ???????????????????????????????????.   ??e?????????????????????? ???????????? ??????????.    ???????????????????????????? ????????? ???У? ??·?????????.???????????????? ???????????????.    ?????????? ??????????? ???????????????? ??????????????????μ????. ??????????????????.

?????????????????: PackageTest/source/?? ??????????? PackageTest???? ????????????? source ????. ?????????:

PackageTest.java
package pktest;
import pktest.subpk.*;
public class PackageTest
{
private String value;
public PackageTest(String s)
{
value = s;
}
public void printValue()
{
System.out.println("Value of PackageTest is " + value);
}
public static void main(String[] args)
{
PackageTest test = new PackageTest("This is a Test Package");
test.printValue();
PackageSecond second = new PackageSecond("I am in PackageTest");
second.printValue();
PackageSub sub = new PackageSub("I am in PackageTest");
sub.printValue();
System.exit(0);
}
}
PackageSecond.java
package pktest;
public class PackageSecond
{
private String value;
public PackageSecond(String s)
{
value = s;
}
public void printValue()
{
System.out.println("Value of PackageSecond is " + value);
}
}
PackageSub.java
package pktest.subpk;
import pktest.*;
public class PackageSub
{
private String value;
public PackageSub(String s)
{
value = s;
}
public void printValue()
{
PackageSecond second = new PackageSecond("I am in subpackage.");
second.printValue();
System.out.println("Value of PackageSub is " + value);
}
}
Main.java
import pktest.*;
import pktest.subpk.*;
public class Main()
{
public static void main()
{
PackageSecond second = new PackageSecond("I am in Main");
second.printValue();
PackageSub sub = new PackageSub("I am in Main");
sub.printValue();
System.exit(0);
}
}

???????У?Main.java??????????????????????????????????????PackageTest.java????pktest????????????????.PackageSecond.java?????pktest??PackageSub????pktest?μ?subpk???????pktest.subpk.?????????????ο??????.