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array of numbers
subjectfact 
array of numbersis a subtopic of Arrays2001-10-19 11:36:07.0
is initialized automatically so that every element has the value 0added by: JK, source: On To Java, 2001-10-19 11:36:07.0
is a kind of arrayadded by: JK, source: On To Java, 2001-10-19 11:36:07.0
arraycan be composed of primitive types or instances of classes    2001-10-19 11:36:04.0
has a fixed size    2001-10-19 11:36:04.0
has a mechanism for preventing access outside the bounds of the array    2001-10-19 11:36:04.0
has a type which is the type of every data item in the array    2001-10-19 11:36:04.0
has example
//the following sums all the elements of an integer array:
for(int i = 0; i < anIntArray.length; i++)
{
sum += anIntArray[i];
}   
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has example of creation
//Create an array called numbers containing 4 integers
int numbers;
numbers = new int [4];
//Or create the array combining the two statements into one
int numbers [] = new int [4];
//Or create the array and initialize it too
int numbers [] = {1, 2, 3, 4};
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has length stored in the instance variable length    2001-10-19 11:36:04.0
is more efficient than specialized collection classes    2001-10-19 11:36:04.0
is object-like but is not a true instance of a class    2001-10-19 11:36:04.0
is zero-based which means the first element is element 0    2001-10-19 11:36:04.0
is created using the new operator2001-10-19 11:36:05.0
is declared using an array declaration2001-10-19 11:36:05.0
is initialized to default values if it is created using new 2001-10-19 11:36:05.0
is not an instance of a class which you can subclass or for which you can write your own code    2001-10-19 11:36:05.0
should be avoided if you do not know beforehand the number of items it will contain    2001-10-19 11:36:05.0
should not be used to manipulate collections of objects    2001-10-19 11:36:05.0
object
when an object is created
  1. the object's variables are set to default values
  2. the constructor of the object's superclass is invoked
  3. the object's initialization block is invoked
  4. the object's constructor is invoked
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  • when an object is not needed any longer
  • the object's space is garbage collected
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can access all instance variables of all objects of its class2001-10-19 11:37:31.0
can be converted into a string using the toString method    2001-10-19 11:37:31.0
can be referred to without reference to the instance variables contained in it    2001-10-19 11:37:31.0
can be referred to by several different variables at the same time    2001-10-19 11:37:31.0
can communicate with every object to which it has access through its public interface2001-10-19 11:37:31.0
can convert itself to a string representation using the toString method    2001-10-19 11:37:31.0
can model    2001-10-19 11:37:32.0
can notify other objects that a condition variable has changed2001-10-19 11:37:32.0
can receive messages from    2001-10-19 11:37:32.0
can represent any entity to which you can associate properties and behaviour    2001-10-19 11:37:32.0
can return its class using the getClass method2001-10-19 11:37:32.0
can send messages to    2001-10-19 11:37:32.0
can wait on 0 or more condition variables2001-10-19 11:37:32.0
communicates with other objects by sending and receiving messages    2001-10-19 11:37:32.0
has part public interface2001-10-19 11:37:32.0
hides methods from other objects using the 'private' keyword2001-10-19 11:37:32.0
inherits instance methods and instance variables from
  • the class to which it belongs
  • all that class's superclasses
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is created by
  • declaring and initializing it such that it is created whenever execution enters a particular block, or, in the case of an instance variable, when an instance is created, for example:
    String aString = "some text";
  • or by declaring it and initializing it later using the new operator, for example:
    String aString;
    aString = new String("some text");
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shares every instance method of its class with the other instances of its class2001-10-19 11:37:32.0
shares its implementation with other instances of its class2001-10-19 11:37:32.0
shares one copy of each class variable of its class with the other instances of its class    2001-10-19 11:37:32.0
to create you use the new operator2001-10-19 11:37:33.0

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