First simple Java program

Previous article introduced fundamental information about Java programming language. Now let’s start create a simple application.

Prerequisite

Before starting this section, please ensure you have some software installed on your machine:

• JRE or JDK
• Setup JAVA_HOME for System environment variable. Please follow the instruction here.
• Text editor (like Notepad++, Emacs, Vim) or IDE (like Eclipse, IntelliJ Idea)
  (for this site, I will use IntelliJ Idea Community Edition for creating program)

Let’s start

Create a java project

• Launch IntelliJ Idea Community Edition > Create a new project
• Select Java
• Set project SDK: browse to JDK directory if the text is not loaded successfully.
• Next
  

• Next
• Set project name and location

It’s done for creating project. IntelliJ Idea will show the project like below.

Now, It’s time for writing code. We need:

Create a package

• Right-click on src > New > Package
• Type package name. The name should be in lower case.

Create a java class and write some code

• Right-click on package that you’ve just created.
• Enter the name of class

Run the program

Finally, it’s time to write simple lines of code. Just copy and paste below code to your created class.

package firstProgram;

public class FirstProgram {
    public static void main(String[] args) {
        System.out.println("Hello tandt53. This is the first java program created by you.");
    }
}

Let’s run this code by right-click on the code and select Run ‘FirstProgram.main()’ and check the result.

Conclusion

Phew!!!! It was a lot of works, right? Now, take 5 mins to review what you’ve done:

• Created a brand new java project
• Add a package and a java class inside
• Write some code and execute it

Those are common steps that you need to do when you’re going to write a java program. However, there are some question inside you mind now.

• Why do you need to follow all of them?
• What are package and class in java?
• What was exactly you just created in java class?

I will go details in the next post to help you clear all above questions. Now take you time to rest. 🙂