Rahul Phadnis

Can some body give me the link to this article. The link on the main page is incorrect. It points to
http://www.javaranch.com/journal/200607/AntPart2.html

Making some changes to the code we can compile it
public class MyClass{ long var; public void MyClass(long param) {var=param;}//1 public static void main(String args[]){ MyClass a,b; a = new MyClass(); // 2 long l =5l; a.MyClass(l); // 3 } }
This also will help to clarify the concepts that previous posters have enlisted.

import java.io.*;//line 1 import java.io.PrintWriter; //line 2 import java.io.OutputStreamWriter; //line 3 public class Foo { public static void main(String[] args) throws Exception { PrintWriter out = new PrintWriter (new java.io.OutputStreamWriter (System.out), true); System.out.println("Hello"); } }
For me using JDK 1.4, the above code compiles and executes without any modifications.

I think this will explain this a bit more
1. base is variable that points to a array of Base objects.
2. obj = base now make obj point to this array of Base objects.
So we cannot cast obj to an array of Sub. The array members may be of type Sub but the array is of type Base
Look at the following code it explains thing a bit more
interface I1 {} interface I2 {} class Base implements I1 {} class Sub extends Base implements I2 {} public class Silver { public static void main(String []args) { Base[] base = {new Sub()}; Sub sub[] = new Sub[1]; Object obj = base; if (obj instanceof Sub[]) { sub = (Sub[]) obj; System.out.println("Cast done"); } else if (obj instanceof Base[]) { Base[] newbase = (Base[]) obj; System.out.println("Cast done"); } else { System.out.println("No Cast done"); } I1 []i1 = (I1[])obj; System.out.println("Trying to cast array member now"); Object o1 = base[0]; //make o1 point to the 1 st member of the array if ( o1 instanceof Sub) { Sub castedsub = (Sub) o1; System.out.println("Cast valid for member"); } else { System.out.println("Not valid cast"); } } }
[ August 23, 2002: Message edited by: Rahul Phadnis ]

Try this to make it absolutely clear
public class TryMe { public static void main(String[] args) { try { double a = 10/0; } catch(ArithmeticException e) { System.out.println("integer arithematic catch"); } try { double B = 10.0/0.0; } catch(ArithmeticException e) { System.out.println("double arithematic catch"); } try { int i =100; int j =0; double C = i/j; } catch(ArithmeticException e) { System.out.println("integer variable arithematic catch"); } } }

With JDK 1.4 beta I get the exception
The jdk version info is
java version "1.4.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta-b65)
Java HotSpot(TM) Client VM (build 1.4.0-beta-b65, mixed mode)
I am running it on Windows 2000 machine
The exception is
java.lang.NullPointerException
at java.io.Writer.write(Writer.java:129)
at java.io.PrintStream.write(PrintStream.java:306)
at java.io.PrintStream.print(PrintStream.java:465)
at java.io.PrintStream.println(PrintStream.java:602)
at com.rahul.certify.java.TestToString.main(TestToString.java:27)
Exception in thread "main"
The code I used to test is
package com.rahul.certify.java; /** * @author rphadnis */ class TestToString { int i; public TestToString(int i) { this.i = i; } public String toString() { if(i == 0) return null; else return "" + i; } public static void main(String[ ] args) { TestToString t1 = new TestToString(0); TestToString t2 = new TestToString(2); System.out.println(t1); //1 System.out.println(t2); //2 } }

I think the confusion is due to the way if is written.
take a look at this modified code
import java.io.*;
public class T010
{
public static void main(String args[])
{
System.out.println( method(0) );
}
static int method(int i)
{
try {
if(i < 0) {
throw new IOException();
}

return 0;

}
catch (IOException e) {
return 1;
}
}
If the argument value is not less than 0, 0 will be returned