Until now, you have used classes from the Java API library by importing the package containing the class or classes you need. A package is a convenient way to organize groups of related classes, and in development, you should organize your application files into packages too. Packages make it easier to locate and use the class files and help you control access to class data at run time.

When your application is fully tested, debugged, and ready for deployment, use the Java^TM Archive file format to deploy the application. JAR file format is a compression and file packaging format and tool for bundling executable files with any other related application files so they can be deployed as one unit.

This lesson shows you how to organize the program files from Part 2, Lesson 6: Internationalization into packages and deploy the executable and other related files to production using JAR file format. Normally, you would use packages from the beginning of development.

• Setting up Class Packages
  • Create the Directories
  • Declare the Packages
  • Make Classes and Fields Accessible
  • Change Client Code to Find the Properties File
  • Compile and Run the Example
• Using JAR Files to Deploy
  • Server Set of Files
  • Fruit Order Client Set of Files
  • View Order Client Set of Files
  • More Information

Setting up Class Packages

For example, the class and other related files for the program files from Part 2, Lesson 6: Internationalization can be divided into three groups of files: fruit order client, view order client, and server files. Although these three sets of classes are related to each other, they have different functions and are to be deployed separately.

Create the Directories

• client1
  • RMIEnglishApp.java
  • RMIFrenchApp.java
  • RMIGermanApp.java
  • MessagesBundle_de_DE.properties
  • MessagesBundle_en_US.properties
  • MessagesBundle_fr_FR.properties
  • index.html
  • rmiFapp.html
  • rmiGapp.html
  • rmiEapp.html
  • java.policy
• client2
  • RMIClient2.java
  • MessagesBundle_de_DE.properties
  • MessagesBundle_en_US.properties
  • MessagesBundle_fr_FR.properties
  • java.policy
• server
  • DataOrder.java
  • RemoteServer.java
  • Send.java
  • java.policy

Declare the Packages

As an example, the package declaration and import statements for the RMIClient2.java class file look like this:

//package declaration
package client2;

import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.*;

import java.io.*;
import java.net.*;

import java.rmi.*;
import java.rmi.server.*;

import java.util.*;
import java.text.*;

//Import server package
import server.*;

Make Classes and Fields Accessible

So client programs can access the fruit order data, the fields of the DataOrder class have to be public too. The RemoteServer class and Send interface need to be public classes, but their fields do not need to be public because the do not have public data.

Fields and methods without an access specifier such as public can only be accessed by objects created from classes in the same package.

Here is the new DataOrder class.

package server;

import java.io.*;

//Make class public
public class DataOrder implements Serializable{

//Make fields public
  public String apples, peaches, pears, cardnum, custID;
  public double icost;
  public int itotal;
}

Change Client Code to Find the Properties Files

The code that creates the messages variable needs to include the directory (package name) as follows:

  messages = ResourceBundle.getBundle(
	"client2" + 
	File.separatorChar + 
	"MessagesBundle", currentLocale);

Compile and Run the Example

Compile

These instructions assume development occurs in the zelda home directory.

Unix:
cd /home/zelda/classes

javac server/Send.java
javac server/RemoteServer.java
javac client2/RMIClient2.java
javac client1/RMIFrenchApp.java
javac client1/RMIGermanApp.java
javac client1/RMIEnglishApp.java
rmic -d . server.RemoteServer
cp server/RemoteServer*.class 
	/home/zelda/public_html/classes
cp server/Send.class 
	/home/zelda/public_html/classes
cp server/DataOrder.class
        /home/zelda/public_html/classes

Win32:
cd \home\zelda\classes

javac server\Send.java
javac server\RemoteServer.java
javac client2\RMIClient2.java
javac client1\RMIFrenchApp.java
javac client1\RMIGermanApp.java
javac client1\RMIEnglishApp.java
rmic -d . server.RemoteServer
copy server\RemoteServer*.class
	\home\zelda\public_html\classes
copy server\Send.class 
	\home\zelda\public_html\classes
copy server\DataOrder.class
        \home\zelda\public_html\classes

---

Note: The rmic -d . server.RemoteServer line uses server.RemoteServer instead of server/RemoteServer so the _stub and _skel classes are generated properly with the package.

---

Start rmi Registry:

Unix:
cd /home/zelda/public_html/classes
unsetenv CLASSPATH
rmiregistry &

Win32:
cd \home\zelda\public_html\classes
set CLASSPATH=
start rmiregistry 

Start the Server

Unix:

  cd /home/zelda/public_html/classes

  java -Djava.rmi.server.codebase=
	http://kq6py/~zelda/classes
  -Djava.rmi.server.hostname=kq6py.eng.sun.com
  -Djava.security.policy=
	server/java.policy server/RemoteServer

Win32:
  cd \home\zelda\public_html\classes

  java -Djava.rmi.server.codebase=
        file:c:\home\zelda\public_html\classes
  -Djava.rmi.server.hostname=kq6py.eng.sun.com
  -Djava.security.policy=
	server\java.policy server\RemoteServer

Start RMIGermanApp Here is the HTML code to load the German applet, Note the directory/package name prefixed to the applet class name (client1/RMIGermanApp.class).

 <HTML>
 <BODY>
 <APPLET CODE=client1/RMIGermanApp.class WIDTH=300 HEIGHT=300>
 </APPLET>
 </BODY>
 </HTML>

  cd /home/zelda/classes

  appletviewer rmiGapp.html

Start RMIClient2 in French

Unix:
  cd /home/zelda/classes

  java -Djava.rmi.server.codebase=
        http://kq6py/~zelda/classes
  -Djava.rmi.server.hostname=kq6py.eng.sun.com
  -Djava.security.policy=client2/java.policy
        client2/RMIClient2 kq6py.eng.sun.com fr FR

Win32:
  cd \home\zelda\classes

  java -Djava.rmi.server.codebase=
        file:c:\home\zelda\public_html\classes
  -Djava.rmi.server.hostname=kq6py.eng.sun.com
  -Djava.security.policy=client2\java.policy
        client2\RMIClient2 kq6py.eng.sun.com fr FR

Using JAR Files to Deploy

JAR files use the ZIP file format to compress and pack files into, and decompress and unpack files from, the JAR file. JAR files make it easy to deploy programs that consist of many files. Browsers can easily download applets bundled into JAR files, and the download goes much more quickly than if the applet and its related files were not bundled into a JAR file.

Server Set of Files

• RemoteServer.class
• RemoteServer_skel.class
• RemoteServer_stub.class
• Send.class
• DataOrder.class
• java.policy

Compress and Pack Server Files

  jar cf server.jar 
	RemoteServer.class 
	RemoteServer_skel.class
	RemoteServer_stub.class
	Send.class
	DataOrder.class
	java.policy

kq6py% jar
Usage: jar {ctxu}[vfm0M] [jar-file] [manifest-file] 
  [-C dir] files ...
Options:
  -c  create new archive
  -t  list table of contents for archive
  -x  extract named (or all) files from archive
  -u  update existing archive
  -v  generate verbose output on standard output
  -f  specify archive file name
  -m  include manifest information from specified 
        manifest file
  -0  store only; use no ZIP compression
  -M  Do not create a manifest file for the entries
  -C  change to the specified directory and 
        include the following file
If any file is a directory then it is processed 
  recursively.
The manifest file name and the archive file name 
  needs to be specified in the same order the 
  'm' and 'f' flags are specified.

Example 1: to archive two class files into an 
  archive called classes.jar: 
     jar cvf classes.jar Foo.class Bar.class 
Example 2: use an existing manifest file 'mymanifest' 
  and archive all the files in the foo/ directory 
  into 'classes.jar': 
     jar cvfm classes.jar mymanifest -C foo/ .

Decompress and Unpack Server Files

  jar xf server.jar

Fruit Order Set of Files

• RMIEnglishApp.class
• RMIFrenchApp.class
• RMIGermanApp.class
• index.html (top-level web page where user chooses language)
• rmiEapp.html (second-level web page for English)
• rmiFapp.html (second-level web page for French)
• rmiGapp.html (second-level web page for German)
• MessagesBundle_de_DE.properties
• MessagesBundle_en_US.properties
• MessagesBundle_fr_FR.properties
• java.policy

Compress and Pack Files

  jar cf applet.jar 
	RMIEnglishApp.class
	RMIFrenchApp.class
	RMIGermanApp.class
	index.html
	rmiEapp.html
	rmiFapp.html
	rmiGapp.html
	MessagesBundle_de_DE.properties
	MessagesBundle_en_US.properties
	MessagesBundle_fr_FR.properties
	java.policy

Decompress and Unpack Files

You can leave the translation files and policy file in the JAR file. When using appletviewer, the applet invoked from the JAR file will find them in the JAR file.

<HTML>
<BODY>
<APPLET CODE=client1/RMIFrenchApp.class
  ARCHIVE="applet.jar"
  WIDTH=300
  HEIGHT=300>
</APPLET>
</BODY>
</HTML>

However, you do need to unpack the web pages so you can move them to their final location. The following command does this. Everything goes on one line.

  jar xv applet.jar index.html 	
	rmiEapp.html 
	rmiFapp.html 
	rmiGapp.html

---

Note: To run the HTML files from a browser, you need to unpack the JAR file, copy the java.policy file to your home directory and make sure it has the right name (.java.policy for Unix and java.policy for Windows), and install Java Plug-In.

---

View Order Set of Files

• RMIClient2.class
• java.policy

Compress and Pack Files

  jar cf vieworder.jar RMIClient2.class java.policy

Decompress and Unpack Files

  jar xf vieworder.jar

More Information

You can find more information on these and other JAR file format topics in the JAR File Format trail in The Java Tutorial.

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