Java Programming - Language Fundamentals - Discussion

public class CommandArgs
{
public static void main(String [] args)
{
String s1 = args[0];
String s2 = args[1];
String s3 = args[2];
String s4 = args[3];
System.out.print(" args[2] = " + s2);
}
}
Save it as CommandArgs.java

Compile it and run the program as follows,
"java CommandArgs 1 2 3 4" and you will get output as args[2] = 2.

class test{
public static void main(String [] args)
{
String s1 = args[0];
String s2 = args[1];
String s3 = args[2];
String s4 = args[3];
System.out.print(" args[2] = " + s2);
}
}

OUTPUT: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 is shown. Any one help me.

args[1]=0(1)
args[2]=0,1(1,2)
args[3]=0,1,2(1,2,3)
args[4]=0,1,2,3(1,2,3,4)

String s2=args[2]

args[2]=0,1,2

Command Args are 1 2 3 4

Result is "ArrayIndexOutOfBoundsException".

Here in the code array size is not given. Then how it will be an exception of ArrayIndexOutOfBoundsException.

@nikhila : Thanks for ur explanation abt Baldevs query .... even me too had the same doubt!

@Baldev.

The above program also gives run time exception since the array index starts with 0 so, declare/initialize the string s1=args[0];

class CommandArgs
{
public static void main(String [] args)
{
String s1 = args[0];
String s2 = args[1];
String s3 = args[2];
//String s4 = args[3];
System.out.print(" args[2] = " + s2);
}
}

Compile and run the program while you run the program give the values there itself like java CommandArgs 10 20 30

You will get the output successfully.

class CommandArgs
{
public static void main(String [] args)
{
String s1 = args[1];
String s2 = args[2];
String s3 = args[3];
//String s4 = args[4];
System.out.print(" args[2] = " + s2);
}
}


now also runtime excption

But
args[0]=CommandArgs
i.e the program name know??

Very nice said. The answer is very clear to me. Thank you.

Very nice explanation and I am searching for these type of questions so if you can possible post more. Thank you.