[thelist] Java
Santilal Parbhu
santilal at scorpioneng.co.nz
Thu Jul 24 00:21:10 CDT 2014
Hi
I am trying to learn Java and I am hoping that someone can help me get my
head around it. Below is the Hello World example. I am finding it very
hard to understand despite two days research on the internet.
/** Comment
* Displays "Hello World!" to the standard output.
*/
public class HelloWorld {
String output = "";
static HelloWorld helloObj; //Line 1
public HelloWorld(){
output = "Hello World";
}
public String printMessage(){
return output;
}
public static void main (String args[]) {
helloObj = new HelloWorld(); //Line 2
System.out.println(helloObj.printMessage());
}
}
The first line creates a new class - correct??
Then the variable "Output" is initialised as a string.
I think static HelloWorld helloObj creates a new class within a class. Why
would you do this?
public HelloWorld(){ - I have no idea what this does??
Then it looks like output is updated to contain "Hello World". Why not just
initialise this to "Hello World" above??
I think the next bit calls the printMessage() method, but I don't know why
it is preceded with "Public String".
I think the "return output" somehow tells the method to print the contents
of output.
Is the last bit the main method of the class. But I don't understand the
construction at all. What is the helloObj = new HelloWorld do.
That last line prints the output, but I thought that printMessagge above did
this.
Can anyone point me to a good resource to help me anwser these questions?
Thanks.
Santilal Parbhu
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