Java Full Course for free ☕
Introduction to Java
In this notes we will cover everything you need to know to get
started with Java programming. Java is one of the top three most
popular programming languages worldwide and is used
extensively by business enterprises, Android apps, and games.
Learning Java can also lead to a high-paying job as a Java
developer.
Why Learn Java?
Java is one of the most popular programming languages
worldwide
Java is an extremely flexible language
Java is used extensively by business enterprises, Android apps,
and games
Learning Java can lead to a high-paying job as a Java developer
Java Basics
Computer languages are on a spectrum between being high level
and low level. Computers only understand binary, which is
referred to as machine code. To create machine code, we write in
a format called source code, which is understandable by humans
and compiles to machine code. When we compile our source code
to machine code, it's machine-specific. Java has an intermediary
step where we can compile our source code to a format called
bytecode, which is cross-platform and can be run on different
machines.
Getting Started with Java
1. Download the Java Development Kit (JDK)
2. Download an Integrated Development Environment (IDE)
3. Create a Java project and class
, Java Development Kit (JDK) contains developer tools to help us
code and a Java Runtime Environment (JRE), which contains a
library toolkit and our Java Virtual Machine (JVM). An Integrated
Development Environment (IDE) provides an interface for us to
write, check for errors, compile, and run code.
To create a Java project, we need a unique name and to configure
the JRE. Adding a class to the project is done by selecting the
project folder, going to file, new class, and selecting a unique
name. The class is a collection of related code, and when we
compile the source code to bytecode, we create a new file with
the dot class file extension.
Introduction to Java Programming
In Java programming, the main method is essential for running
the program. It is contained within the outer set of curly braces of
the class and any code within it will execute starting from the top
and working its way down. To print text to the console window,
we can use
the System.out.print or System.out.println methods. The
latter adds a new line character at the end of the text, while the
former does not. We can also use escape sequences such as \
n for a new line character or \t for a tab character.
Adding a Main Method
In order to run our code, we must have a main method within the
class. We can generate this method by checking the "public static
void main" checkbox when creating the class. If we accidentally
remove the method, we can simply type it in ourselves: public
static void main(String[] args) { }. Any code within this
method will execute when we run the program.
Printing to the Console Window
To print text to the console window, we can use
the System.out.print or System.out.println methods. To
display text within double quotes, we must use an escape
sequence for the quotes: \". Similarly, to display a backslash, we
must use \\. We can also use escape sequences such as \n for a
new line character or \t for a tab character.
Introduction to Java
In this notes we will cover everything you need to know to get
started with Java programming. Java is one of the top three most
popular programming languages worldwide and is used
extensively by business enterprises, Android apps, and games.
Learning Java can also lead to a high-paying job as a Java
developer.
Why Learn Java?
Java is one of the most popular programming languages
worldwide
Java is an extremely flexible language
Java is used extensively by business enterprises, Android apps,
and games
Learning Java can lead to a high-paying job as a Java developer
Java Basics
Computer languages are on a spectrum between being high level
and low level. Computers only understand binary, which is
referred to as machine code. To create machine code, we write in
a format called source code, which is understandable by humans
and compiles to machine code. When we compile our source code
to machine code, it's machine-specific. Java has an intermediary
step where we can compile our source code to a format called
bytecode, which is cross-platform and can be run on different
machines.
Getting Started with Java
1. Download the Java Development Kit (JDK)
2. Download an Integrated Development Environment (IDE)
3. Create a Java project and class
, Java Development Kit (JDK) contains developer tools to help us
code and a Java Runtime Environment (JRE), which contains a
library toolkit and our Java Virtual Machine (JVM). An Integrated
Development Environment (IDE) provides an interface for us to
write, check for errors, compile, and run code.
To create a Java project, we need a unique name and to configure
the JRE. Adding a class to the project is done by selecting the
project folder, going to file, new class, and selecting a unique
name. The class is a collection of related code, and when we
compile the source code to bytecode, we create a new file with
the dot class file extension.
Introduction to Java Programming
In Java programming, the main method is essential for running
the program. It is contained within the outer set of curly braces of
the class and any code within it will execute starting from the top
and working its way down. To print text to the console window,
we can use
the System.out.print or System.out.println methods. The
latter adds a new line character at the end of the text, while the
former does not. We can also use escape sequences such as \
n for a new line character or \t for a tab character.
Adding a Main Method
In order to run our code, we must have a main method within the
class. We can generate this method by checking the "public static
void main" checkbox when creating the class. If we accidentally
remove the method, we can simply type it in ourselves: public
static void main(String[] args) { }. Any code within this
method will execute when we run the program.
Printing to the Console Window
To print text to the console window, we can use
the System.out.print or System.out.println methods. To
display text within double quotes, we must use an escape
sequence for the quotes: \". Similarly, to display a backslash, we
must use \\. We can also use escape sequences such as \n for a
new line character or \t for a tab character.
