INFO0062 - Object-Oriented Programming - Programming with …grailet/docs/INFO0062/2019... · 2020-02-19 · Installing Java Programming with Java Annex: about Linux Installing Java

INFO0062 - Object-Oriented ProgrammingProgramming with Java

Jean-François Grailet

University of Liège

Faculty of Applied Sciences

Academic Year 2019 - 2020

Installing Java Programming with Java Annex: about Linux

Summary

Installing Java

Recommended solutions to get started with Java

• Using javac / java with a CLI

• Using Eclipse IDE

Annex: about Linux

• For future computer scientists

• Solutions to get started with Linux

1 / 20

Installing Java


Installing Java

No matter how you will program with Java, you have to install Java first.

Indeed, Java programs run in virtual machines.

• They are not directly compiled into executables like C or C++ programs

• Cf. Chapter 2, slides 31-32

You therefore need a compiler (javac) and a virtual machine (java).

Hopefully, you can install both of them at once.

Remark: before reading next slides, make sure you don’t have Java already.

• Use your search bar or program manager to check this.

• Note that some installations can be incomplete for this course.

E.g., they include a virtual machine but don’t come with a compiler.

• In this case, you can install the version of Java mentioned in next slides.

2 / 20


Installing Java (II)

What you want to install is the Java SE Development Kit.

• SE = Standard Edition

• Comes with both javac and java

• Current version1: 13.0.2

You can download it on Oracle’s website.

Remark: Java’s lattest version is for 64-bit hardware only.

• Hopefully, basically all computers nowadays have a 64-bit architecture.

Contact a teaching assistant if you are using a 32-bit hardware.

• We will review how to install Java on your machine.

1 i.e., at the time of creating this document3 / 20

https://www.oracle.com/technetwork/java/javase/downloads/index.html


Installing Java (III)

4 / 20


Installing Java (IV)

Upon download, don’t forget to accept the license agreement.

You can download the uncompressed installers.

You can then use them right away to install Java.

• Follow the steps normally; you don’t have anything special to do here.

5 / 20


Installing Java (V)

6 / 20


Installing Java (VI)

Linux users can also use the following commands to install Java.

Ubuntu 18.04 LTS (and onwards)

sudo apt updatesudo apt install default-jresudo apt install default-jdk

Older distributions (including 32-bit systems)

sudo apt-get updatesudo apt-get install default-jresudo apt-get install default-jdk

7 / 20


No computer ? No worries

You can use the freely accessible computers at the Montefiore Institute (B28).

• Located on the first floor, near employees’ lunch room

• They can be seen from the bridge between B28 and B37

• Run with Ubuntu; already have javac and java

• Can help you if you don’t have a laptop or your own home computer

Note that you can’t use them right away.

• You need to create a Montefiore account to log in on them.

• You also have to bring your own mouse (or rent one). 2

Contact a teaching assistant for more details on the matter.

2Some people apparently stole mouses a few years ago. God knows why.8 / 20

http://www.student.montefiore.ulg.ac.be/accounts.php

Programming with Java


Getting started with Java

For this course, we suggest you two approaches.

Both works on any common OS (Operating System3).

Using javac / java with a CLI

• CLI = Command Line Interface

• Also called command prompt4 under Windows

• A CLI consists in using your computer by typing text commands

Using Eclipse IDE

• IDE = Integrated Development Environment

• An IDE is a piece of software designed for developping large programs

Note that in both cases, you will have to install Java first.

3FR: système d’exploitation; exemple: Windows 104FR: invite de commandes

9 / 20


Using javac and java with a CLI

javac and java are the traditional tools to compile and run a Java program.

• javac: compiles .java files

• java: runs compiled Java programs

The reason why there are two pieces of software is Java’s design.

• javac produces bytecode (as .class files).

• This code can only be interpreted by a Java Virtual Machine (JVM).

You can use both tools with CLI under any OS (i.e., Windows, macOS, Linux).

10 / 20


Using javac and java with a CLI (II)

11 / 20


Using javac and java with a CLI (III)

Pros5

• No need to install additional software (except a text editor, if none)

• Light interface (CLI along with a text editor)

• Once you’re used to it, it’s quick and easy to use

• Perfect to compile and run small programs

Cons6

• You have to learn how to use a CLI (can be confusing at first)

• Needs to modify Windows’ settings to get it working on it

5FR: avantages6FR: désavantages

12 / 20


Using Eclipse IDE

Eclipse is a very popular IDE to create Java programs.

It’s available for any common OS.

Provides at the same time code edition and compilation/running.

Provides a rich GUI (Graphical User Interface) with many tools.

• Syntax checking

• Interface checking (i.e., checking if your methods are correctly invoked)

• Project manager (to review the architecture of a Java program)

• Spell checker7

• Etc.

7FR: correcteur orthographique13 / 20


Using Eclipse IDE (II)

14 / 20


Using Eclipse IDE (III)

Pros

• Rich GUI, comes with many useful tools

• All-in-One

• Can be more user-friendly than CLI to beginners

• Can be useful if your future courses include large Java projects

Cons

• Has to be installed in addition to Java itself

• Designed to build large Java programs

In INFO0062, we will only write small programs

15 / 20


How to choose your solution to program with Java

What’s your OS (Operating System) ?

LinuxmacOSWindows

Is Computer Science your thing ?

Is Computer Science your thing ?

Yes No No Yes

Install Java & EclipseInstall Java, modify thePATH variable and usethe command prompt

Install Java and use your terminal

16 / 20


What’s next ?

Next, read the dedicated tutorial for the solution you chose.

Also, if you are a (future) computer scientist, consider the annex.

• At this point in your studies, you might want to consider using Linux.

17 / 20

Annex: about Linux


A few words on Linux

At this point in your studies, you probably have heard about Linux a lot.

• Some teacher(s) may have introduced you to the Linux terminal.

• You might have used University computers running with Linux distributions.

• ... and maybe some zealots tried to convert you to Linux !

Why is it a big deal in computer science ?

• Most Linux distributions are free and their code is publicly available.

• Programming under Linux is usually much easier.

• This is especially true for simple programs.

• With practice, using a terminal is also handier8 than a GUI.

Computer scientists should consider using Linux.

8FR: plus pratique, plus commode18 / 20


How can I use Linux ?

You can discover and use Linux without modifying or dumping your current OS.

• Running a Linux distribution in a virtual machine (FR)

• Using a bootable USB stick (EN)

You can also dual boot (FR) your computer.

• Both your original OS and Linux will co-exist on your computer.

• You will select the OS to run when powering-up your computer.

• Requires to partition your disk space.

• Don’t do this right now if you are not confident about modifying your disk.

19 / 20

https://openclassrooms.com/courses/reprenez-le-controle-a-l-aide-de-linux/installez-linux-dans-une-machine-virtuelle

https://tutorials.ubuntu.com/tutorial/tutorial-create-a-usb-stick-on-windows

https://lecrabeinfo.net/installer-ubuntu-18-04-lts-dual-boot-windows-10.html


Which Linux distribution should I pick ?

Typically, Ubuntu ("Linux for human beings") is recommended for beginners.

• Has a complete GUI for browsing files and running programs

• Has its own store to install additionnal software

• Terminal is not essential for a beginner to use it

Other popular distributions you can consider using

• Mint

• Fedora

20 / 20

https://linuxmint.com/

https://getfedora.org/

Documents

INFO0062 - Object-Oriented Programming - Programming with …grailet/docs/INFO0062/2019... · 2020-02-19 · Installing Java Programming with Java Annex: about Linux Installing Java