LearningArray.java

// Include this if you want to use toString method to print the array
import java.util.Arrays;

public class LearningArray {

	public static void main(String[] args) {

		// Creating a reference to an Array of integers
		int[] iArray;
		
		// Allocating 10 integers in memory
		iArray = new int[10];
		
		// Set the contents of each element of the array with their index
		// For an array with 10 elements first index is 0 and last is 9
		iArray[0] = 0;
		iArray[1] = 1;
		iArray[2] = 2;
		iArray[3] = 3;
		iArray[4] = 4;
		iArray[5] = 5;
		iArray[6] = 6;
		iArray[7] = 7;
		iArray[8] = 8;
		iArray[9] = 9;
		
		// Print array
		System.out.println(Arrays.toString(iArray));
		
		// Deallocating array, Garbage Collector will take care of it ;-)
		iArray = null;
		
		// Creating a constant array
		int[] iArray2 = {
			10, 20, 30,
			40, 50, 60,
			70, 80, 90
		};

		// Find out how big my array is
		System.out.println(iArray2.length);
	}

}

// What if I don't import Arrays?
// Using System.out.println(iArray.toString()); will call toString from Java Object which will print the hash code of the object. Not very user friendly.

// Do I have to allocate the array before using it?
// Yes. Otherwise you'll get a NullPointerException. BOOM!

// What if I want change my array dinamically by adding and removing elements?
// Use something else. Like Collections framework.

// Can I instantiate an array like this:
// int iArray[];
// ?
// Yes. But according to Java tutorials "this form is discouraged".

// Can I change the size of my array once it was instanciated?
// No. Length is a final property that holds the number of positions of an array.
// Please note that it is not the number of elements, because if there is a null
// element in an array it counts as a position but not as an element.
// A possible solution is to create another array, with the new desired size and copy the elements
// from the old array to the new array.