please explain the mechanism of this try block statement

[vineet chaturvedi]

try {
System.out.println("Entering" + " try statement");

out = new PrintWriter(new FileWriter("OutFile.txt"));
for (int i = 0; i < SIZE; i++)
out.println("Value at: " + i + " = " + vector.elementAt(i));

can someone explain me mechanism of this try block statement how is it dealing with exception ???

[Bear Bibeault]

The code is incomplete. We'd need to see the rest of the code.

[vineet chaturvedi]

here is the full code ...

public void writeList() {
    PrintWriter out = null;

    try {
        System.out.println("Entering" + " try statement");

        out = new PrintWriter(new FileWriter("OutFile.txt"));
        for (int i = 0; i < SIZE; i++)
            out.println("Value at: " + i + " = " + vector.elementAt(i));
                  
    } catch (ArrayIndexOutOfBoundsException e) {
        System.err.println("Caught ArrayIndexOutOfBoundsException: "
                           +  e.getMessage());
                                 
    } catch (IOException e) {
        System.err.println("Caught IOException: " +  e.getMessage());
                                 
    } finally {
        if (out != null) {
            System.out.println("Closing PrintWriter");
            out.close();
        } 
        else {
            System.out.println("PrintWriter not open");
        }
    }
}

[vineet chaturvedi]

thank you very much for this.....i will take care this in future...

can you please explain me the question please ???

[Jeff Verdegan]

vineet chaturvedi wrote:can you please explain me the question please ???

You asked, "how is it dealing with exception?" What do you mean by that question? What don't you understand? Have you gone through a java exception tutorial yet?

[vineet chaturvedi]

okay first of all tell me what type of code is this in the above program me

out = new PrintWriter(new FileWriter("OutFile.txt"))


is it a object ,constructor or what it is ???

[Matthew Brown]

vineet chaturvedi wrote:okay first of all tell me what type of code is this in the above program me

out = new PrintWriter(new FileWriter("OutFile.txt"))


is it a object ,constructor or what it is ???

That's just creating a new object, and then using that as an argument to the constructor when creating a second new object. It's equivalent to this:

FileWriter writer = new FileWriter("OutFile.txt");
out = new PrintWriter(writer);

I assume you follow those two lines? The only difference is that in the original version we haven't kept a reference to the intermediate object, whereas in the second we could refer to afterwards using the writer variable. It's nothing to do with exceptions, though.

[James X Peterson]

When an error occurs within a method, the method creates an object and hands it off to the runtime system. The object, called an exception object, contains information about the error, including its type and the state of the program when the error occurred. Creating an exception object and handing it to the runtime system is called throwing an exception.When you get an exception in try block related exception object will be thrown from try block and it will be caught by the corresponding catch block. In your code if ArrayIndexOutOfBoundsException is raised then first catch block will be executed,if IOException is raised second catch block will be executed. finally is the block that will execute regardless of exception raised or not.

Regards,
James