Java CommandLine Arguments

Command line arguments are used to read the values from keyboard(pass the values while running of the program)

class Addition
{
public static void main(String args[])
{
System.out.println("Before converting "+(args[0]+args[1]));
}
}

Output
Java Addition 12 12
Before Converting 1212
In the above example addition of two number are concated because CommandLine Arguments are by default strings.To overcome this problem Wrapper classes are introduced.

Wrapper class

Wrapper classes are used to convert the string format to appropriate Primitive Datatypes.

Wrapper classes
Constants	Wrapper Class	Datatype	Method
Integer	Byte	byte	x=Byte.parseByte(args[0])
	Short	short	x=Short.parseShort(args[0])
	Integer	int	x=Integer.parseInt(args[0])
	Long	long	x=Long.parseLong(args[0])
Floating point	Float	float	x=Float.parseFloat(args[0])
	Double	double	x=Double.parseDouble(args[0])
Character	Character	char	x=args[0].charAt(0)
String	String	String	x=args[0]

class Addition
{
public static void main(String args[])
{
System.out.println("Before Converting "+(args[0]+args[1]));
int x,y,z;
x=Integer.parseInt(args[0]);
y=Integer.parseInt(args[1]);
z=x+y;
System.out.println("After Converting "+z);
}
}

OUTPUT:
Java Addition 12 12
Before Converting 1212
After Converting 24
Next Topic: Java Operators