Introduction to Java

Java is a general-purpose modern programming language initially developed by Sun Microsystems, and currently owned by Oracle Corporation.

The key feature of the language is platform independence: it means that the same Java program can be run on multiple platforms without any changes! This principle is also known as "write once, run anywhere" (or WORA).

A short history of Java

The Java language project was initiated in 1991 by James Gosling and his colleagues. In the beginning, the language was called "Oak." Later the project was renamed "Java" as a reference to Java coffee. For this reason, the language’s logo is a cup of coffee.

Sun Microsystems released Java 1.0 in 1996. After that, new versions were released every 1 to 3 years. Since Java 9, released in 2017, new versions have been released every 6 months. You can read more about its history and find the most recent version here.

Some important features of Java

As we've mentioned before, the most important feature of Java is platform independence.

Another important feature is a simple and clear syntax

If you have ever written programs in C/C++, you know that manual memory cleaning can lead to bugs in the code. Fortunately, Java has a garbage collector that automatically cleans memory from unused objects during runtime.

Java supports multiple programming paradigms

▫️SIMPLE JAVA PROGRAM

class Main {
    public static void main(String[] args) {
        System.out.println("Hello!");
    }
}

NOTE:-

• 123 is an integer number, "123" is a string;
• 'A' is a character, "A" is a string;
• '1' is a character, 1 is an integer number.

The basic terminology

• Program – a sequence of instructions (called statements), which are executed one after another in a predictable manner. Sequential flow is the most common and straightforward sequence of statements, in which statements are executed in the order that they are written – from top to bottom in a sequential manner;
• Statement – a single action (like print a text) terminated by semi-colon (;);