Java and TextPad configuration

Java JDK installation

Many computers already have a Java runtime version (JRE) installed. You also need to install the JDK - Java Development Kit (previously known as the SDK - System Development Kit). The JDK download contains the same things as the JRE download plus additional tools for development. If the JRE is not installed or is not a current version, it can be installed as part of the JDK installation process.

Java's Feature releases are numbered 1.4, 1.5, ...
There will also be Update releases 1.5.0_01 and Maintenance releases 1.5.1

Install Java to a folder using only the Feature release number. This will require selecting the Custom install option and Changing the suggested folder during the install process.

When future releases occur, they can be installed in the original Feature release folder -- this will greatly simplify your system maintenance.

It is OK to have multiple versions of Java installed but you do not need anything more than the current JRE and JDK. Java is not like Microsoft with its DLL hell. Later versions of Java will always run class files compiled in an earlier version without any trouble. You can even compile Java programs to run in an earlier version.

Before, During, and After installation...
• Sun Java website
  • New to Java Programming Center - getting started
  • Java 2 Platform, Standard Edition (J2SE)
    download the latest non-beta version of the JDK and documentation
  • Eclipse Installation Notes and Tutorials
  • The Java Tutorial
    an excellent resource
  • Java Technology Concept Map - a very cool way of navigating the Java language interactively
  • Java 2 Platform, Standard Edition Documentation, version 1.5.0
    You will find your local copy of the downloaded documentation faster than using Sun's site over the Internet.
  • Search JDK Documentation on Sun's site
  • API Specifications vs. API Developer Documentation
• Setting Up and Getting Started
• Installation Notes for Microsoft Windows
• Another set of installation instructions and another for problems compiling under Win98

After installation...
• Solving Common Compiler and Interpreter Problems
• The Java Ranch is always a good place to look for help of any kind.
• See the University of Ottawa's excellent FactGuru knowledge base about Java
• Java Knowledge Base
• very complete sets of notes and examples on Java topics from Dr. Mark Lanthier, Carleton University
• Sun's Java technology developer newsletters

Java configuration check

After installing the Java JDK (download it from Sun), check if there is a PATH to the Java commands...
• open a Command Prompt window and enter the command:
• C:\> java -version
  • if the system can find the program, it should respond with something like:
    java version "1.5.0_04"
    Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_04-b05)
    Java HotSpot(TM) Client VM (build 1.5.0_04-b05, mixed mode, sharing)
    
• try C:\> javac -version and javadoc as well
• the C:\> path    command will show where the system is looking for the java?.exe programs
  • ...\jdk1.5\bin; (corresponding to the installation folder) should be listed amoung the directories
• if you cannot remember where or if Java was installed, open a Command Prompt window and enter the command:
• C:\>dir java.exe /s
• do the same for the javac.exe and javadoc.exe files

Redefine the Windows path variable so it can find Java
• Control Panel/System/Advanced tab/Environment Variables button. (menu directions based on Windows 2000, XP)
• Edit/Add the User or System Variable: PATH
• to contain the value: C:\Program Files\Java\jdk1.5\bin or wherever your Java JDK was installed plus the "\bin" directory.

System can find Java but Java cannot find your .java or .class files

Depending on the history of Java packages installed on your PC, Windows may be using a CLASSPATH environment variable which tells Java where to look for .java and .class files.

check if CLASSPATH is set...
• open a Command Prompt window and enter the command:
• C:\> set classpath    and see what you get.
• If there is no classpath environment variable, Java will look in the current directory which is generally where you want it to look.
• If there is something there, Java will use it. Make sure that "." [a period] is at the beginning of the CLASSPATH so Java looks in your current directory.

Fix the CLASSPATH Option 1 (preferred if a classpath exists)

Redefine the Windows classpath variable...
• Control Panel/System/Advanced tab/Environment Variables button. (menu directions based on Windows 2000/XP)
  • Edit/Add the User Variable: CLASSPATH
  • to contain the value: .;%CLASSPATH%
  • i.e. put the current directory "." before any System classpath.
  • do not include quotation marks even if the path includes folder names with embedded blanks.
• Windows 98
  • you may have to modify your AutoExec.bat file:
    SET CLASSPATH  .;%CLASSPATH%

Fix Option 2 (overrides existing classpath environment variable)

Modify TextPad...
• TextPad menu: Configure / Preferences and expand Tools
• click Compile Java
  • change its Parameters to:  -classpath  .  $File
    and the Initial folder should be:  $FileDir
• click Run Java Application
  • change its Parameters to:  -classpath  .  $BaseName
    and the Initial folder should be:  $FileDir
• "-classpath . " is a javac/java command line parameter which overrides the CLASSPATH Environment Variable to the current directory for the running of that command
• you must include quotation marks if the path includes folder names with embedded blanks.

TextPad cannot find java.exe or javac.exe

From TextPad help:
To be able to use Java with TextPad, the Java JDK must be installed using its setup program. This writes information to the registry, which TextPad cannot work without.

Unfortunately, it seems the current setup program may not do this. See this page to fix the registry.

Create Java Documentation from within TextPad

TextPad comes configured to compile and run Java applications and applets. See the Tools menu. You can customize TextPad to run a batch file which creates Java documentation.

The runJavaDoc.bat file can be found in the first three week's download sample files. It creates Java documentation for you in a separate subdirectory. You may want to add the "-private" switch to the javadoc command in the batch file to force javadoc to document not only the public interfaces to your code but also your private variables and methods.

In TextPad
• open the Configure menu
• Preferences
• expand Tools
• click Add button in upper right
• add a Program
• use the Open dialogue to find your runJavaDoc.bat file
• click Apply

Now, under the Tools menu, you should see your javadoc item which you can run at any time in addition to compiling and running your Java applications.

.jar files

A Java .jar file is a single file that contains a package of classes (usually many .class files within a directory structure).

In the beginning of the course, you may wish to use the Seneca bobjects (business objects) package to do GUI programming without the gooey programming. DOWNLOAD the package, documentation, and instructions.

Later in the course, we will use a jar file containing the AS/400 Toolkit for Java that allows us to access iSeries databases and functions.

Usually, Java .jar files containing classes your programs use should be placed in the Java "extensions" directory (folder) which is usually the \jre\lib\ext subfolder of the Java installation directory. e.g.
C:\Program Files\Java\jdk1.5\jre\lib\ext

Find out which ext directory your Java installation is using by running the Welcome2.java program from Week 1, ShowJavaProperties from Week01GUI.zip or run

System.getProperty( "java.ext.dirs" );