JAVA- 1-D Array Creation

How to Create an Array:-

Every Array in java is an object.
Hence we can create an array by using new operator or keyword.
example:-

    int [ ] a=new int [3] ;

 

Rules For Creating an Array:-

1.At the time of Array creation compulsory, we should specify the size otherwise, we will get compile time error.

example:-

 int [ ] x= new [ ];         (invalid)

 int [ ] x= new [ 6 ];      (valid)



2.It is legal to have an Array with size 0 in java.
example:-
 int [ ] x= new [ 0 ];      (valid)


3.If we are trying to specify array size with negative int value then we will get RunTime Exception saying
" NegativeArraySizeException". 

example:-
 int [ ] x= new [-3 ];       (invalid)

RuntimeException:-    " NegativeArraySizeException".  

But we won't get any Compile Time Error.The code will compile fine. 


4.To specify Array size allowed data types are the byte, short ,char ,int.
If we are trying to specify any other than that then we will get compile time array. 

 example:-


int [ ] x= new [ 10];                   (valid)
int [ ] x= new [ 'a'];                    (valid)

byte c=20
int [ ] x= new [ c];                      (valid)
short s=30;
int [ ] x= new [ s];                      (valid)



int [ ] x= new [ 10 L];                (invalid)
Compile Time Error:- Possible loss of precision
                                 found:-long
                                  required:-int 



5.The maximum Array size in java is 2147483647 which is nothing but the maximum value of int data type.

 int [ ] x= new [ 2147483647];              (valid)

 int [ ] x= new [ 2147483647];              (invalid)

Compile Time Error:Integer Number Too Large 


Note : In the 1st example of rule 5 we may get Runtime Exception if sufficient heap memory is not available.

Back to Part 1.ArrayDelaration 
                                                                           
 Next: Part 3. 2-D Creation

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