Example Program:
class HelloWord { public static void main(String args[]) { System.out.println(“Welcome to Java”); } }
Explanation:
class HelloWord:
- Class is a keyword and HelloWord is the name of the class.
public:
- The public keyword is an access specifier, which means that the content of the class can be accessible from everywhere.
static:
- The keyword static allows main() to be called without creating an instance of a class because it is the first method that will be called when program executes
void:
- The keyword void tells the compiler that main () does not return any value.
main():
- main is a method called first when a java application begins
- Java is case-sensitive. Main is different from main
String args[]:
- It declares a parameter named args, which is an array of class string.
- args[] receives any command-line argument supplied with main() at the time of execution.
System.out.println():
- System is predefined class that provides access to the system.
- Out is the output stream that is connected to the console.
- Output is displayed by the built-in println() or print() Println() displays the string which is passed to it.
- It is similar to a printf() function of the C language
Compilation
Javac HelloWord.java
- This command will compile the source file and if the compilation is successful it will generate a class file with the same name as of the class (HolloWord.class). It contains bytecode
Java HelloWord
- This command called ‘java’ takes the bytecode and runs the bytecode on JVM environment in interpreted mode.
- Output: Welcome to Java