Step 2 - Create Java classes VM from a Ubuntu VM
Instructions assume that you are using Linux. If you are using Windows, you need to make some small adaptations.
user@host:~$ mkdir JavaClasses user@host:~$ cd JavaClasses user@host:~/JavaClasses$
Before we continue, we need to introduce a few Linux commands:
- mkdir - to make a directory on Linux.
- ls - to list the contents of the current directory.
- cd - to change the current directory.
Now copy the following files to the JavaClasses directory:
Next, start the virtual machine using the following command:
user@host:~/JavaClasses$ vagrant up
This last command will take some time and download a lot of files from the Internet. But, don't worry, if you correctly manage Vagrant you will never need to download all that again. We will take a snapshot called "clean". A snapshot is a virtual machine state. We take a snapshot because we want to go back to that state later.
Now that we have installed everything it is time to take our main snapshot:
user@host:~/JavaClasses$ vagrant halt user@host:~/JavaClasses$ vagrant snapshot take clean
That is it. At this point you should have everything you need to start the lessons. But it is worth checking if everything is working fine. So if there was any glitch on the installation you can try to fix it.
Checking the installation
Next we will bring the virtual machine up again and connect to the its console:
user@host:~/JavaClasses$ vagrant up user@host:~/JavaClasses$ vagrant ssh
Depending on your platform, Vagrant will complain on the first command that the virtual machine was already running, but such complaint is harmless. After the second command you will see the following:
Welcome to Ubuntu 14.04.1 LTS (GNU/Linux 3.13.0-36-generic i686)
* Documentation: https://help.ubuntu.com/
System information as of Tue Oct 7 14:30:31 UTC 2014
System load: 0.41 Processes: 78
Usage of /: 2.6% of 39.34GB Users logged in: 0
Memory usage: 15% IP address for eth0: 10.0.2.15
Swap usage: 0%
Graph this data and manage this system at:
https://landscape.canonical.com/
Get cloud support with Ubuntu Advantage Cloud Guest:
http://www.ubuntu.com/business/services/cloud
0 packages can be updated.
0 updates are security updates.
vagrant@vagrant-ubuntu-trusty-32:~$
This means you have successfully installed a new virtual machine and Vagrant is working fine.
Your first Java program
Type the following on the terminal:
vagrant@vagrant-ubuntu-trusty-32:~$ echo 'class A { public static void main(String[] args) { System.out.println("Hello World!"); }}' > A.java
vagrant@vagrant-ubuntu-trusty-32:~$ javac A.java
vagrant@vagrant-ubuntu-trusty-32:~$ java A
You will see
Hello World!
Congratulations! You just created your first Java program, compiled it, and executed it!
Don't worry about the details. We will see later what each of those commands mean.
Now let's clean everything so you can start anew:
vagrant@vagrant-ubuntu-trusty-32:~$ exit user@host:~/JavaClasses$ vagrant snapshot go clean vagrant@vagrant-ubuntu-trusty-32:~$
The following section will introduce the basic concepts of Vagrant. So these commands will start to make more sense.
Next, Vagrant tutorial or Step 3
Now you can proceed to the Step 3, the lessons or Mini Vagrant Tutorial.