Let's begin with looking at the July API We will also see how it is structured and we will actually 2
explore the AP on articles website Bulos or discuss a little bit about third party appeals. 3
And finally we will look at a gradual sedation by an item an effective Jalla Joe IPY is a library of 4
hundred softball district classes. 5
Angela ate for example has over 4200 classes and these classes are read by experts like Josh Knoblock 6
who's the author of effective gello book and the API is already used by millions of programmers. 7
So it's really very district court and we can safely use it without having to write any of that court 8
ourselves. 9
On from First up don't you know that July be-I is part of both JDK and Jerry enjoy AAPI or in any professional 10
product classes are grouped into something called package's packages are basically directories on the 11
file system and you use a particular class you have to load a package that contains the class hit are 12
some packages within the July B.A. and some of the classes they contain are shown beneath them. 13
For example John Howard utl package contains classes like our analyst on Hashima later you will understand 14
why packages are named in this way with multiple keywords supported by Dart's next the question is why 15
do we need packages instead of providing one horrendously large pile of classes packages provide meaningful 16
organization. 17
Just imagine browsing through all the photos in an art classes in the July IPA. 18
So it's going to be very tedious. 19
So structuring them in a meaningful way based on their functionality is definitely helpful. 20
For example all classes that are present because doctors are grouped into that package. 21
John why don't you do so any time you are looking for a particular data structure. 22
Then we can go and look in the package. 23
John what are you. 24
Packages also help in name scoping. 25
For example Dallas has two different classes by the same name called deed. 26
One is inside the package I couldn't. 27
The other is inside another package called Jawad askew in little packages. 28
It would not be possible to have both these classes. 29
An packages also help in security for example you may want to restrict parts of your class to be inaccessible 30
outside of its package that is only classes within that package should access those parts. 31
Not Let's quickly look at some commonly used packages in Java IPA hostess delegate line package it includes 32
classes that are fundamental to Java. 33
One of the classes in this package is a stringless which we will see pretty soon next is Djala that 34
you package it mainly classes representing various sophisticated instructors. 35
Later we will look at different classes and this package next is your package I will hear means input 36
or clauses in this package are used for doing stuff like reading from a file or writing a file. 37
Next is dollar dot net package it includes classes to handle networking related to us like downloading 38
a web page another commonly used one is not as your package and that's used for retrieving and storing 39
data in databases. 40
So these are some commonly used packages. 41
And there are many more as the course progresses be learn about several classes that go into some of 42
these packages. 43
Not Let's go ahead and briefly explore the Java API on Oracle's Web site just go ahead and google for 44
Djala eight API and just click on the first link which is hosted on Oracle's website. 45
So it's the Java API documentation so this is the API documentation. 46
And here there are different frames here in the top frame. 47
You can see all the packages listed here are these are all the packages. 48
And beneath that you can see all the classes. 49
So by default it shows all the packages and all the classes. 50
And here you have some description. 51
So let's just go ahead and click on one of the packages. 52
So here you can see a dot like package which is the R which has all the fundamental classes Angello 53
that I will package. 54
Now if you click on one of the packages it will show all the classes in that particular package. 55
And it also shows the interfaces interfaces will be discussed later when covering object oriented concepts 56
. 57
So here are all the classes that you can see in Jawa dot line package. 58
So let's just go ahead and click on string and Asuna also knows you play constraint class. 59
You will see that all the description of the string class or here. 60
So this contains all the details about the string class. 61
Ok so here is the signature of the string class and some description about the string class what what 62
this class does. 63
And then if you scroll down you can see the fields that are used within this class. 64
So this is one feat. 65
And here is a summary of all the constructors so you can see that there are off constructors and stringless 66
with different parameters. 67
So these are all overloaded constructors and if you further scroll down it will show all the methods 68
that this class has. 69
OK so these are all the matters that the class has so it just gives the name of the method the method 70
signatures here are and the written type on a short description about the matter. 71
So same holds for all the constrictors too. 72
It has a short description about each of the constructors and if you click on one of these matters so 73
it gives you the all the details about that particular matter. 74
OK. 75
So this is the this includes the entire description. 76
This is an odd description about this particular matter. 77
And here is the matter signature. 78
So that's the API. 79
So you just browse it on you will be using a lot of this as you double up in products. 80
This is what you will rely on. 81
Now here that you are you can actually change this just make it 7 and it will show you the Java 7 API 82
documentation you can if you change it to six it will show you that. 83
So that's supported That's the API. 84
And let's just head back with us Fife's on finished the rest of the lesson. 85
So something looked at the July API but when we're looking professional projects you will need several 86
advanced features that may not be supported by the standard July API alone. 87
Luckily I was blessed with tons of third party appeals most of which are open source so you can freely 88
use them and even customize them as per your needs this they're going to show the different components 89
that commonly make up a complex e-commerce website the diagram also shows the third party job be ice 90
. 91
These components may use on the abs are shown in parenthesis for example you can see that there are 92
projects like Apache Commons on Google go to and these projects include specialized libraries for using 93
advanced data structures or to perform routine programming tasks like string manipulation often says 94
libraries and group features that are not supported by standard July IPA or even if they're supported 95
. 96
These libraries may be providing more efficient alternatives. 97
Google Goolwa is mostly over by Google engineers and it is very good we are not going to discuss any 98
of these abs but you can look at the resources section just to learn about what these libraries have 99
to offer. 100
Next is it from effective Java. 101
I am 47 and it says that no I use the libraries according to this item here are some benefits that good 102
AP ice pro-ID focus on writing new logic without having to reinvent the wheel. 103
So it's a lot of time as you don't have to write the functionality yourself and deal with any potential 104
bugs that may come out of it. 105
Yes also tend to improve their performance over time. 106
There is performance of existing functionality would be improved in newer versions of the API. 107
You you know over time. 108
AP has also gained new functionality. 109
So you should make yourself familiar with important parts of both standard API and also other third 110
party API. 111
So try to be the API documentation for all the classes to be covered in this course although we will 112
cover all the important details. 113
So that's about it. 114
And in the next few lessons we will focus exclusively on packages. 115
Thank you.