Java Arrays Java arrays fall between a primitive data type and an object Properties of Java arrays: can contain objects, primitive types, or other arrays contents are accessed via zero-based positive integers enclosed within the brackets, [, and ] declaration and creation of arrays are distinct operations created with the new operator uninitialized arrays have a value of null have a single instance variable called length checks at run time, that all accesses are between 0 and length - 1 passed to methods by reference byte buffer[]; // array declaration (buffer = null) buffer = new byte[1024]; // array creation (contents initialized to zeros) int table[] = new int[10]; // declaration and creation combined int sqrs[] = {0, 1, 4, 9, 16, 25, 36, 49, 64, 81 }; // with an initializer buffer[5] = sqrs[sqrs.length-1]; // array references int triangle[][] = new int[3][]; triangle[0] = new int[3]; triangle[1] = new int[2]; triangle[2] = new int[1];
	Lecture 2		Slide 9		6.837 Fall '98

In Java arrays fall somewhere between a primitive data type and an object

• Arrays of any object, primitive type, or arrays can be formed
• Array contents are accessed via zero-based positive integers enclosed within the bracket operators, [, and ]
• Arrays are passed to methods by reference, the actual values in any array may be changed any methods that receives it as an argument
• Declaration and creation of arrays are distinct operations in Java
• Like objects, arrays are created with the new operator, and uninitialized arrays have a value of null
• Arrays have a single instance variable called length
• Arrays check at run time, that all accesses are between 0 and length - 1