String in java

String in java

Strings are extensively used as a data type and it allows the programmer to handle words ,sentences ,phone number,or even just usual numbers.fundamentally String as an object that represents a sequences of character values.

String class

String class can be available in java.lang package. we can use String class in side the lang package .

In java String is a collection of character that can be enclosed in the double quotes.

ex: char []={'j','a','v','a'};

In above example String is a class and str is a object of String class that can be store the characters of string. we can store the character  of String but we can't Store the complete String.in java this method is not allowed but other programming languages allows this method like cor c++ etc.

There are several methods are available in String to perform operations of String like concat() method ,replace() method ,reverse() method etc.

example

class Test
{
public static void main(string arg[])
{
string s="viren";
s.concat("shram");
System.out.println(s);
     }

}

output

viren


Difference between String  and String Buffer   class:
There are several difference between String Buffer and Builder class as follows.

1. when we create a object of String class we can't perform any operation of existing object.if we perform any operation of  then a new object will be created such type of non-changeable  functionality is called immutable string.

ex: String s=new String("viren");
     s.concat("sharma");
o/p: viren

when we create object of String Buffer class ,then we can change everything and perform any operation of  existing object such kind of changeable  functionality  is called mutable string.

ex: String s=new String("viren");
     s.concat("sharma");

o/p: virensharma

2. In java String class equals() method is override the content   comparison .hence objects are different but content must be same  than equals() returns true.

ex: String s1=new String(viren) 
     String s2=new String(viren)
Sopln(s1==s2);             //false
  sopln(s1.equals(s2));  // true

]

In java String Buffer class equals() method is not over ride for content comparision  hence, when objects are different and content must be same then equals() returns fals

StringBuffer  sb1=new StringBufferr(viren) 
     StringBuffer sb2=new StringBuffer(viren)
Sopln(s1==s2);             //false
  sopln(s1.equals(s2));  // false