Java - Learn Unique Features with Real Code Examples
Find out why Java remains the top choice for developers and explore its extensive ecosystem, syntax, standard libraries, and GUI capabilities.
Why Java?
Before you embark on an exciting journey of learning Java, let's stop for a moment and understand why Java can become your main programming language. Created in 1995 by Sun Microsystems, Java is platform independent, which means it can run on different types of devices - be it your mobile phone or a supercomputer. It has a rich ecosystem supported by an extensive library, well-designed syntactic structure and many frameworks such as Spring and Hibernate. As of September 2021, 69.74% of developers worldwide use Java, according to a Stack Overflow survey. So, if you're looking to update your skill set or work on enterprise-level applications, Java could be the change you've been looking for.
Your first Java program: Hello world!
Let's get real hands-on and look at a simple Hello World program. in Java. This is not just an example; It's a rite of passage for every programmer. Take a look at this snippet:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello , World!");
}
}
Here we have a class called HelloWorld . The main method serves as the starting point for executing the program. Inside this method we use System.out.println to display the text "Hello world!" on the console. This program serves as an introduction to basic Java syntax, which we will cover in detail as we go. The code uses English-language constructs and is quite easy to read, even if you are new to programming.
Java Building Blocks
One of the key strengths of Java is its object-oriented nature. Classes serve as blueprints for objects that carry attributes (variables) and behavior (methods). Consider the following example:
class Dog {
String name;
String breed;
void bark() {
Sy stem.out.println(name + " says: Woof!");
}
}
In this example, we define a class Dog with two attributes, name and breed , and one method bark() . Object-oriented programming helps organize code and promotes code reuse.This makes software development more intuitive and aligned with the way people experience the world—through objects and the interactions between them. When you're working on large-scale applications, using objects helps you break complex tasks into manageable pieces.
Syntax and Semantics
When it comes to syntax, Java is simple yet robust. A semicolon (;) denotes the end of a statement, and curly braces {} group together blocks of code. Case sensitivity is another aspect; for example, System and system are not the same thing in Java.
Here is an example of a code with a cycle for:
= 0; I <10; i ++) { syntem.aut.println (i);}
The code demonstrates a for loop to print the numbers 0 to 9. The keyword for initiates the loop and the conditions are in parentheses. Unlike some other languages, you don't need additional characters such as colons or indents to indicate the body of the loop; parentheses do the job.
Java Standard Library
Java comes with an extensive standard library, offering pre-written classes and methods to perform common tasks. For example, Java provides the ArrayList class as part of its java.util package for implementing dynamic arrays. Here's how to create an ArrayList and add elements to it:
import java.util.ArrayList;
ArrayList
names.add("Alice");
names.add("Bob");
In this code, you imported the ArrayList class from the java.util package. Then you created an ArrayList object named names and added two names to it. Instead of writing code from scratch to implement these data structures, you can take advantage of Java's built-in features, saving time and resources.
Swing and JavaFX
Need to create a desktop application? Java offers several libraries for creating graphical user interface (GUI), such as Swing and JavaFX. Although Swing is an older and less efficient framework, it is still widely used for simpler applications.
For example, creating a main window in JavaFX involves:
import javafx.application.Application;
import javafx.stage.Stage;
public class HelloWorldFX extends Application {
@Override
public void start(Stage stage) {
stage.setTitle("Hello World");
stage.show();
}
}
In this fragment the class Application from the JavaFX library serves as the basis. The start method is overridden to set the window title and display it. Using frameworks like JavaFX, you can easily create complex and interactive desktop applications.
JUnit: ensuring code quality through testing
Testing is an integral part of software development. Java supports various types of testing through frameworks such as JUnit, which are widely used for unit testing. With JUnit, you can easily write tests to test the functionality of your code, making it more reliable and resilient.
For example, to test a method that sums two numbers, you could write:
import static org.junit.Assert.assertEquals;
import org.junit.Test;
public class CalculatorTest {
@Test
public void testAddition() {
Calculator calc = new Calculator();
assertEquals(5, calc.add(2, 3));
}
}
In this example, the annotation is @T est indicates that the testAddition method is a test to execute. The assertEquals method checks whether the add method in the Calculator class adds numbers correctly.
Your future with Java
There you have it, a detailed guide to the unique features of Java. From its object-oriented nature to its robust library, Java has something for everyone. Whether you're just starting out or looking to diversify your skills, Java's versatility and community support make it an attractive choice. So why wait? Dive into the world of Java today and discover a world of possibilities!
