need explanation in java 2011

[saneha]

Respected Sir,

Please explain the following terms and conditions with suitalbe examples if possibles. as they always arise a big confusion for me,

console,

command line arguments,

object References whose are automatic inialized with Null,

variables and inttance variables,

intantiating of an object.

[Vuhelper]

1) Console:
This term is used in various places in computer science. In most commonly console refers to the command line interface, where we enter our commands like DOS provides us with console.

2) Command line arguments:
Arguments that are provides while running the code through command prompt.

e.g. Copy file1 fil2 ,

In the above example we have made program named Copy that copies contents of file1 to file2,
While running it we provide source and destination files at command prompt with the program name, now these two arguments are called command line arguments.

3) Class members are automatically initialized to default values
Local variables (method or constructor variables) are not automatically initialized
Arrays, whether field or local variables, are automatically initialized to the default values of their declared type

4) An instance variable is a variable defined in a class (i.e. a member variable), for which each object in the class has a separate copy.

Where as only a single copy exists of Class Variable for each object

5) Instantiating of an object
The new operator instantiates a class by allocating memory for a new object and returning a reference to that memory. The new operator also invokes the object constructor.