Introduction to Java

 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.

Comments and Multiline Comments

Comments are text within the code that are ignored by the compiler. They can be used to leave notes for ourselves or others who may be looking at our code. Single line comments begin with // and multiline comments are enclosed within /* */.

Tips and Tricks

Changing the IDE Color Scheme

To change the color scheme of your IDE, go to Window > Preferences > General > Appearance > Theme and select the desired theme. The dark theme is a popular choice among programmers.

Customizing the Console Window

To customize the color scheme of the console window, go to Window > Preferences > Run/Debug > Console and select the desired colors for the text and background.