Hello, World Program in Notepad:
Open Notepad and type the following code:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello World");
}
}
Save the file as Hello.java
. You can do this by clicking on File > Save As and then selecting the directory where you want to save the file. Make sure to type the filename as Hello.java
and select All Files in the Save as type dropdown menu.
Open the command prompt and navigate to the directory where you saved the Hello.java
file.
Compile the program by typing javac Hello.java
and pressing Enter.
If there are no errors, run the program by typing java Hello
and pressing Enter. The program will output “Hello, world!” in the console.
java -cp /tmp/jLRff3bu2p HelloWorld
Hello World
Output
Hello World
If you want to learn Java, refer to our Java Fundamentals blog.
Java Hello World Program Explanation
- class: The
class
keyword is used to declare a class in Java.
- public: The
public
access modifier makes the class visible to all.
- static: The
static
keyword means that the method can be called without creating an object of the class.
- void: The
void
return type means that the method does not return any value.
- main: The
main
method is the entry point of the program.
- String[] args: The
System.out.println()
method is used to print a string to the console.
- System.out.println(): The
System.out.println()
method is used to print a string to the console.
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Java Comments
It is useful to place a comment in place to indicate what you are doing. It is added into the program for making the program easier to understand and these are not compiled by the compiler or interpreter. It is useful if you want someone else to be able to ever read your code.
There are two ways to declare comment in java which are as follows:
- Single Line comment
- Multi-Line comment
Learn the basics of Operators in Java through this blog!
Single Line comment in Java:
It is used to apply the comment on a single line. To apply single line comment // is used.
Example:
System.out.println("Hello World"); // It will print Hello World
Multi-Line comment in Java:
It is used to apply the comment on multiple lines.
Example:
System.out.println("Hello World"); /* It will print
Hello World */
Check out the list of Hibernate Interview Questions to prepare for upcoming interviews.
Keywords in Java Programming
Keywords are also known as reserved words which express a special meaning to the compiler and interpreter. Keywords in Java are –
abstract |
assert |
boolean |
break |
byte |
case |
catch |
char |
class |
const |
continue |
default |
do |
double |
else |
enum |
extends |
final |
finally |
float |
for |
goto |
if |
implements |
import |
instanceof |
int |
interface |
long |
native |
new |
package |
private |
protected |
public |
return |
short |
static |
strictfp |
super |
switch |
synchronized |
this |
throw |
throws |
transient |
try |
void |
volatile |
while |
|
|
Learn how to use threads in Java to improve performance. Start your Multithreading in Java journey today!