This course will be retired on January 8, 2022.
Heads up! To view this whole video, sign in with your Courses account or enroll in your free 7-day trial. Sign In Enroll
Preview
Start a free Courses trial
to watch this video
In order to code fancy applications, developers rely heavily on other people's code, or *libraries*. These libraries are made available as JAR files to anyone who wants to use them. In this video, you'll be introduced to the process of using a third-party library in your own code.
Welcome back.
0:00
If you're here now, Im guessing you
have IntellaJ installed and ready to go.
0:01
Nicely done.
0:05
If not, be sure to hit up
the forum with your questions and
0:06
the community can help you get going.
0:09
The next tool I wanna discuss will be used
to manage the third party libraries we
0:12
use in our project.
0:16
Namely, the spring libraries.
0:18
The spring framework that we'll be using
is not included in the Java core library.
0:21
That being the case, we'll need to save
those libraries into our projects so
0:25
that we can use the familiar
import statements
0:29
to reference spring code from
the code that we're writing.
0:32
Technically this amounts to adding
JAR files to the class path.
0:36
The who and the what now?
0:40
Let's dissect that a little bit,
starting with the class path.
0:42
If you've been through some
of our previous courses,
0:46
you may have experience
using the class path.
0:48
In Java, the class path consists of one or
0:51
more directories that contain all the Java
files associated with our project.
0:54
This is an option we can specify,
while compiling or running a Java program.
0:59
[NOISE] So if there are outside code
libraries, the directory where they're
1:03
saved should be a part of the class path
[NOISE] that's given to the Java compiler
1:07
while compiling, and
to the Java virtual machine while running.
1:12
Hey, speaking of code libraries,
1:16
let's circle back to another term I
mentioned just a few moments ago.
1:18
I said that we'll need to add
JAR files to the class path.
1:22
What are these JAR files?
1:26
If you haven't guessed yet,
1:28
these are indeed the code
libraries I'm referring to.
1:30
Let's take a closer look.
1:33
JAR stands for Java Archive.
1:35
A JAR file is essentially
a bundle of compiled Java code.
1:37
The files are bundled together
just like a zip file.
1:42
Except that the Z-I-P extension,
a JAR file has the J-A-R extension.
1:45
What this amounts to is that you can write
a bunch of Java code then distribute that
1:51
code as an application or
library by generating a JAR file.
1:56
Generating one of these can be done from
most Java IDEs, including IntelligiJ, or
2:00
from the command line with
the JDK's JAR command.
2:05
After generating a JAR file,
all developers need to do is
2:09
download the JAR file that you've created
and add its location to their classpath.
2:12
Then they can start creating and
2:17
interacting with objects from
the classes that you defined.
2:19
Since the JAR file only
includes your pipe code,
2:23
they can do this without you ever
having to reveal your source code.
2:26
Now, that's pretty cool stuff.
2:30
As a heads up on terminology,
I'll be using the terms JAR and
2:32
library synonymously.
2:35
Let's take a short break here and
in the next video
2:38
we'll talk about how we're going to
fetch all those fancy libraries.
2:41
It turns out that the tool we're gonna use
2:45
is one of the most widely
used tools in the industry.
2:47
You need to sign up for Treehouse in order to download course files.
Sign up