Monday, 30 July 2012

strictfp Keyword in java

In java  strictfp   is used to strict all the calculations of  to strictly follow the strict floating point calculations in all platforms.

It can be used with class , interfaces and non-abstract methods. If used with the method then it ensures all the calculations inside that method must follow floating point math. When used with the class then it ensures all calculations inside that class must follow floating point math.

Compile-time constant expressions must always use strict floating-point behavior

It providestotal platform-independency and  take advantage of the speed and precision of the extended precision floating-point operations supported by x86 CPUs 

JAVA Standard Edition 5.0


JAVA 5.0 ( also known as Standard Edition 5.0 or J2SE 5 or J2SE 1.5) :-

Codename:- TIGER

1. Initially released in September 2004.

2. Has 3200+ classes and interfaces.

3. Introduced several updates and improvements

Annotations:- Anotations wrere used to provide meta-data for the programs so that it can be easily understand for metadata-aware programs.

Generics:-Generics are used to provide types of object belonging to collections. So that type safety cab be gauranteed at compile time.

Autoboxing :- Autoboxing is used to automatically convert from primitive types to wrapper clsses.

Improved syntax for looping :-Improved syntax of loops was introduced like for each loop

Varargs :- Provide flexibility to pass variable no of arguments.
                 Prefer Post

Friday, 13 July 2012

Jagged Array in Java

Java support jagged array. U can have different no of length for each column do don't need to have same no of column for all rows.




Example:-



package javaTest;


public class JaggedArray {
public static void main(String ar[])
{
int[][] a=new int[2][];
a[0]=new int[2];
a[1]=new int[4];
a[0][0]=1;
a[0][1]=12;
a[1][0]=10;
a[1][1]=3;
a[1][2]=12;
a[1][3]=13;
System.out.println("length-"+a.length);
for (int i = 0; i < a.length; i++) {
for (int k = 0; k < a[i].length; k++) {
System.out.print(a[i][k]+" , ");
}
System.out.println("");
}


}


}



Output:-



length-2
1 , 12 , 
10 , 3 , 12 , 13 , 


Varargs in java (Passing variable no of arguments in java program)

After J2SE 5.0 java supports passing of variable arguments in a method that u don't need to fix the no of arguments at the time of defining the method .
Compiler automatically converts the arguments in the form of array so u can access all the arguments at run time.





Example:-


public class Varargs
{

    public static void main(String[] args)
    {

        Varargs var = new Varargs();

        var.show("Ankit", "Singh", "Katiyar");

        var.show("facebook.com\"", "ankitkatiyar91");

    }

    public void show(String... arg)

    {

        for (int i = 0; i < arg.length; i++)

        {

            System.out.println(arg[i]);

        }

    }

}



Note:- it   works only it version J2SE 5.0 or above.

You can use any data type for variable arguments.

Example:-

package javaTest;

public class Varargs {

public static void main(String[] args) {
// TODO Auto-generated method stub
Varargs var=new Varargs();
var.show(1,2,3);
var.show(9,7);

}
public void show(int... arg)
{
for(int i=0;i<arg.length;i++) 
{
System.out.println(arg[i]);
}
}

}

Rules :-
* For any method it must be the last argument.