The Java training online
Capsis can be run on several systems. This training can be followed under Linux, Windows or MacOSX. Installations are required before starting the exercises: an expected version of the Java Development Kit and the Java exercises archive must be installed, see blow.
Where is the terminal ?
During the training, you will need to enter commands in the terminal.
In the terminal, you are always located in a directory: the current directory (or folder), you can see it in the prompt (where you are supposed to type a command)
Under Linux and Mac, the commands are the same (Unix commands) and '~' means 'your home (personal) directory'
|Linux / MacOSX||Windows|
|see the current directory||
|get the list of files in this directory||
|move down into a directory||
|move up one directory||
|create a new directory in the current directory||
You need a Java Development Kit (JDK) installed, version 1.8 (higher may be ok).
Note: if you find a Java Runtime Environment (JRE), this can run Java programs but you will not have the java compiler we need to write Java programs, so a JDK must be installed.
Check this by entering the following two commands in your terminal, from whatever directory, they should both return the same version of Java.
|All operating systems|
|version of java (i.e. the Java Virtual Machine, JVM) runs the java programs)||
|version of the java compiler (to build java programs)||
E.g. under Linux: both commands return version 1.8.0, correct (the number after the
_ does not matter here)
coligny@marvin-13:~$ java -version java version "1.8.0_101" Java(TM) SE Runtime Environment (build 1.8.0_101-b13) Java HotSpot(TM) 64-Bit Server VM (build 25.101-b13, mixed mode) coligny@marvin-13:~$ javac -version javac 1.8.0_101 coligny@marvin-13:~$
Where can I find Java ? (download)
The reference Java for Capsis is the version JDK 1.8 by Oracle, you may find it there:
Applicationsfolder (where you like).
How to tell the system this is the default Java ? (PATH)
Once installed, if the check upper is still not ok, you may still have to update the PATH system variable to tell your system this is the default Java (some installers may do it, some others not).
When you type a command (or program name) in the terminal, the system looks in the current directory. If not found there, it looks in order in the directory names listed in an environment variable named PATH (same under Linux, MacOSX and Windows), until it finds the command.
You need to change this PATH variable to add a directory at the top of the list: the directory containing the
javac you've just installed.
Open a file manager, go to the directory you've installed or unzipped your Java, find the bin/ directory containing the
javac programs and copy its name in the clipboard with Ctrl-C.
For Windows, find the environment variables configuration (Try
Configuration Panel > System > Advanced > Environment Variables), find the 'System' section, locate the PATH variable in the list, edit it, add the new directory name (Ctrl-V) then ensure it is at the top of the list.
For Linux Ubuntu users, the PATH may be tuned in the file /etc/environment, e.g. below to be adapted for your machine (use a ':' between the paths), then type 'source /etc/environment'
Note: setting other variables like the CLASSPATH or JAVA_HOME is not needed here, neither for these exercices, nor after for the Capsis end-users or modellers (see the pages about compilation in the Capsis Documentation page).
Only the applications starting after you changed the PATH will now the correct path for Java: close and reopen the opened terminals. Check your configuration (see previous section) until you get the expected answer for both
To write your programs, you need a simple text editor with few features including syntax coloring (colors for the Java keywords…). If you already have one, you can use it, else look at one of these:
The new directory must be somewhere you can access easily on your machine, you can create a directory with the terminal and
mkdir, or with your file manager.
// Reminder: 'somewhere>' means: you are in the directory named 'somewhere', you may // type your command... // E.g. (Windows) create a directory named 'practice' in C:\ with mkdir: C:\> mkdir practice // Good examples (Windows or Linux): C:\practice> /home/coligny/practice> // Poorer example (Windows), too long, with accents and spaces in names: C:\Documents and Settings\My Documents\éléments de formation\formation capsis janvier 2021\practice>
java/to write your Java exercises.
For the following Java exercises, you will need to reach this
practice/java/ directory in the terminal with
cd like this:
// E.g. (Windows) create a directory named 'java' in 'practice' C:\> cd practice C:\practice> mkdir java C:\practice> cd java C:\practice\java>
The capsis training archive contains a directory named capsis4/ and a copy of capsis to be used only for the time of this training course.