Arrays - A Concise and Practical Introduction to Programming Algorithms in Java - page 86

System . out . println ( prime . length ) ;

We cannot change the size of arrays once initialized. For example, trying to force
the length of array array by setting array.length=23; will generate the fol-
lowing compiler message error: cannot assign a value to final variable
length .

4.2.4 Index range of arrays and out-of-range exceptions

Arrays created with the syntax array=new TYPE[Expression] have a fixed
length determined at the instruction call time by evaluating the expression
Expression to its integer value, say l (with l=array.length ). The elements
of that array are accessed by using an index ranging from 0 (lower bound) to
l

1 (upper bound):
array[0]
...
array[l-1]
A frequent programming error is to try to access an element that does not
belong to the array by giving an inappropriate index falling out of the range
[0 ,l

−

1]. The following program demonstrates that Java raises an exception if
we try to use out-of-range indices:

−

Program 4.2 Arrays and index out of bounds exception
class ArrayBound {
public static void main ( String [ ] args )

{ int []v= { 0,1,2,3,4,5,6,7,8 } ;
long l=v. length ;
System . out . println ( "Size of array v:" +l ) ;
System . out . println (v [ 4 ] ) ;
System . out . println (v [1 2]) ;

}

}

Running the above program yields the following console output:
Size of array v:9
4
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 12
at ArrayBound.main(ArrayBound.java:8)
That is, index out of bounds cannot be checked by the compiler and may
happen at any time when executing the program.
A subarray is a consecutive portion of an array: For example, array[3..7]; .
Java does not provide language support for manipulating subarrays so that one
has to explicitly keep track of the lower and upper bounds of subarrays.