CSE 142: Computer Programming I, Winter 2015

1) Install Java Development Kit (JDK)

Macs with the OS X operating system will have the Java compiler available automatically or will download and install it automatically, so you should be able to skip this step. But many Macs have an out-of-date version of JDK, so you may need to install the latest Mac version of JDK. Some newer Macs (purchased within the last 3 years or so) may already have this software, but older ones do not. If you have a fairly new Mac, try to skip to Step 2 and see if jGRASP works, and if not, come back to this step. You might also want to run your Mac's built-in Software Update feature to see if it updates your Java for you.

You can test whether your Mac has Java installed (and if so, what version) using the Terminal application. To run the terminal, use your Spotlight icon at the upper-right of your screen to search for Terminal. It will find and suggest the Terminal application. Click it to run the terminal. A white window will appear with black text and a blinking cursor for you to type commands. Type the following command and press Enter, to see your version of Java:

java -version

If your Mac doesn't have Java installed already (or has an obsolete version installed), you can go to the web page below to download it. Once you've downloaded the file, double-click it on your desktop to install it.

• Find jdk-7u75-macosx-x64.dmg on this page. Be sure to "Accept License Agreement."

2) Download jGRASP editor

http://jgrasp.org/

There is a Mac version of jGRASP, available from the same jGRASP web site by clicking the button labeled jGRASP pkg.

Once you have downloaded the jGRASP application PKG file, double-click it to install jGRASP. At each screen, you can choose the default options and click "Continue" or "Install" to move forward. If you've done it correctly, you will see an "Install Succeeded" message and a green checkbox.

Once jGRASP is installed, you can run it from your Applications folder, Dock, or by typing "jgrasp" into your Spotlight search at the top-right of your screen.

Common Mac jGRASP issues:

• Some students are reporting issues with jGRASP on the Mac. Some report seeing the following strange message:

  share cache file is corrupt: /var/b/yl/yl_share_cache_ppc
  

  If you see this message, you should update your Mac to Java v1.6 by running the Mac's built-in Software Update tool. Then re-run jGRASP and click Settings, jGRASP Startup Settings, and set your Java version to 1.6.0.

• If you see an error message on startup of jGRASP that has a "jGRASP Startup Settings" button, click it. Then where it says "Java executable (for running jGRASP):" it will probably say [Default]. Clear that out and instead, type in:

  /usr/bin/java
  

  Click "Ok" and close the error message window. Then re-open jGRASP and the problem may go away.

• Some students are reporting that characters are missing from their println messages on the console. We don't know what is causing this. If you have this bug, let us know what kind of Mac you have (Intel or PPC? What OS X version? etc.) and we'll try to figure it out.
• If you continue having problems with jGRASP, you may want to try another Java editor named DrJava.

(These directions are a few months out of date, but the general idea can still be followed.)

It's tougher to give an installation guide for Linux because of the large variety of different distributions and architectures. Here is a rough guide that will work for many distributions such as Ubuntu.

1) Install Java Development Kit (JDK)

If you use Ubuntu Linux (or a derivative thereof), you can install Java through their apt-get package manager system. Type the following three commands:

sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"
sudo apt-get update
sudo apt-get install sun-java6-jdk

Otherwise, get Java from Sun/Oracle's web site:

http://java.sun.com/javase/downloads/index.jsp

Follow the above link and click the "Download" button next to the "JDK 6.0 Update 21". (NOT the "with NetBeans 5.0" link or the "with Java EE" link or others). Accept the License Agreement and choose the "Linux self-extracting file" file:

jdk-6u26-linux-i586.bin

(If you use a Linux distribution that supports RPM packages such as Fedora Core, you may wish to use the "Linux RPM in self-extracting file" package.)

Once you have finished downloading the JDK .bin file, open a terminal window and execute the file. You may have to give execution permissions to the file:

chmod +x jdk-6u26-linux-i586.bin
./jdk-6u26-linux-i586.bin

Running the .bin file extracts the JDK contents. Move these to a directory of your choice. (The rest of this tutorial assumes you have moved the JDK to /usr/lib/jdk/ .)

After installing Java, you will probably wish to add Java's directory to your PATH setting, so that you can run Java commands from your terminal. To do so, edit the file .bashrc in your home directory and add the following lines to the end of it:

export PATH=/usr/lib/jdk/bin:$PATH
export CLASSPATH=.

You should close your terminal and open a new one for the PATH changes to take effect.

2) Download jGRASP editor

http://jgrasp.org/

There is a Linux version of jGRASP, available from the same jGRASP web site by clicking the button labeled jGRASP zip. Download this file and extract its contents. Then open a terminal and cd to the directory of those contents and type:

java -jar jgrasp.jar

3) Set Up BASH Script File (optional)

If you are unable to get the jGRASP debugger working in Linux, try downloading the following jgrasp BASH script file and putting it in the jgrasp/bin folder. Give it execute permissions (chmod +x) and then use it to run jGRASP.

jgrasp bash script

Enable File Extensions in Windows:

By default, Windows does not show extensions of certain types of files. This can lead to confusion because you may not know which file is your .java program and which is your .class compiled file.

If you'd like to change this value, open My Computer. From the window's main menu, click the following:

Tools, Folder Options...

A Folder Options window will appear. Click the tab labeled View, then find the checkbox labeled Hide extensions for known file types. Uncheck it. Press OK.

Now all files should show their extensions in Windows.

International Error Messages:

Some users who have international (Chinese, Korean, etc.) versions of Windows cannot properly see the compiler errors in jGRASP. To fix this problem, follow these steps in jGRASP.

Click "Settings" -> "Compiler Settings" -> "Workspace".

In the settings box that pops up, click the "Flags / Args" tab (in the lower row of tabs). Then, click the black "button" under "FLAGS or ARGS" and next to "Compile". In the text box that becomes available type in "-J-Duser.language=en" (without the quotes) and click "OK".

(Thanks to TA Eric Spishak for writing this tip!)

Unable to install 64-bit jGRASP on Windows 7 / Vista:

Some Windows 7 / Vista users report that their system just sits idle when they double-click the Java JDK installer icon. They are unable to install JDK. Usually this problem can be solved in one of two ways:

1. Try installing the 32-bit version of JDK (sometimes labeled the "x86" version on the Sun/Oracle download page), or
2. Try installing JDK v1.6 instead of 1.7.