Explain hello world program in java

👉Explain hello world program in java

This program has two main parts: ■ All the program is enclosed in a class definition—here, a class called HelloWorld. ■ The body of the program (here, just the one line) is contained in a routine called main(). In Java applications, as in a C or C++ program, main() is the first routine that is run when the program is executed. You’ll learn more about both these parts of a Java application as the book progresses. Once you finish typing the program, save the file. Conventionally, Java source files are named the same name as the class they define, with an extension of .java. This file should therefore be called HelloWorld.java. Now, let’s compile the source file using the Java compiler. In Sun’s JDK, the Java compiler is called javac. To compile your Java program, Make sure the javac program is in your execution path and type javac followed by the name of your source file: javac HelloWorld.java Note: In these examples, and in all the examples throughout this book, we’ll be using Sun’s Java compiler, part of the JDK. If you have a third-party development environment, check with the documentation for that program to see how to compile your Java programs. The compiler should compile the file without any errors. If you get errors, go back and make sure that you’ve typed the program exactly as it appears in Listing 1.1. When the program compiles without errors, you end up with a file called HelloWorld.class, in the same directory as your source file. This is your Java bytecode file. You can then run that bytecode file using the Java interpreter. In the JDK, the Java interpreter is called simply java. Make sure the java program is in your path and type java followed by the name of the file without the .class extension: java HelloWorld

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👉(// What the meaning of each part (public, static, void, main, String and args): public class Program { public static void main(String[] args) { System.out.println("This is my first code. Awesome!"); } } // public: Mean that main () can be call from anywhere // static: Mean that main () does not belong to a specific object // void: Mean that main () returns no value // main: is the name of a function. Main is special because is it start of a program // String: mean the data type // args: args is the argument passed to the function. "args" is not special and you can name it to anything else and the program would work the same)