Head First Java exercise

[Leandro Lavore]

Hey guys, i'm an absolute greenhorn both in Java and in forums. I am reading Head First Java second edition and trying to be a good student i'm doing all the exercises. I couldn't really figure out what's going on in this simple program. The code is like this:

package javaapplication10;

/**
 *
 * @author Leandro
 */
public class Mix4 {
    
    int counter =0;
    
    public static void main(String[]args){
    
    int count=0;
    
    Mix4[]m4a=new Mix4[20]; 
    
    int x =0;
    
    while(x<9){//[1,]
    
        m4a[x]= new Mix4();
        m4a[x].counter=m4a[x].counter+1;
        count=count+1;
        count=count+m4a[x].maybeNew(x);
        x=x+1;
        
    }
    System.out.println(count+" "+m4a[1].counter);}
    
    public int maybeNew (int index){
    
        if(index<5 ){
        
            Mix4 m4= new Mix4();
            m4.counter=m4.counter+1;
            return 1;
        }
        return 0;
            
        }
    
    }

   
  The console writes: 9 1

I imagine that the method maybeNew has the command return 1;, so that's why i get that number in the console print, but i can't get my head around the logic of this program. Any help would be more than welcome.

Thank you very moosch

[Campbell Ritchie]

Welcome to the Ranch

Which page is it on?
The Mix exercises in HFJ (=your book) are exercises in following the execution of a program. I think the only way to solve them is to write them on paper. You will end up with something like this:-

Start: count = 0
m4a = [][][][][][][][][][][][][][][][][][][][]
x < 9? yes: enter loop
m4a = [0][][][][][][][][][][][][][][][][][][][]
m4a[0].counter increases by 1
m4a = [1][][][][][][][][][][][][][][][][][][][]
... etc

Or maybe it would be quicker to write in a text file on screen. When I wrote the array as [][][]... that isn't quite accurate; it should really be [null, null, null, null...]