String

1. 
   
   

   // you have two type of string just like a string is

   // normal and one string is declare using new keyword so both

   //  of string save on heap memory and without new keyword use

   //  string save in heap memory and one memory in the heap memory scp (string constant pool)

   
   
   

   public class string1 {

       public static void main(String[] args) {

           String a= "Rakesh";

           String b= "Rakesh";

           System.out.println(a==b);

   
   

           // out is true because a and b same same value adress

           // output is very clear true because this value store in

           // scp(string constant pool)

   
   

           String c = new String("Rakesh gupta");

           String d = new String("Rakesh gupta");

           System.out.println(c==d);

   
   

           // out put is false because stored in heap memory and heap memory can always be change  

          

       }

   }
2. 
   

   // so i will use String in java and how add in other

   // string so and why i can't add other string in previous string

   
   

   public class string2 {

       public static void main(String[] args) {

           String s1= "Rakesh";

           System.out.println(s1);

   
   

           // output is rakesh because and

           // then try add a other string in previous string

           // for adding string i will use .cancat methode

   
   

           s1.concat("Gupta");

           System.out.println(s1);

            

           // their are no changes because this string store in scp (String constent poo)

   
   

           //  and then use stringbuilder or Stringbuffer

          

           StringBuilder s2 =new StringBuilder("Rakesh");

           System.out.println(s2);

   
   

           // and then try to add a string

            s2.append ("Gupta");

            System.out.println(s2);

   
   

           //  and here output is sure add and you one thing

           // always remember concat methode not work  with String

           // builder refrences and here is append methode you follow this

           // blog offcouse i share on this blog all thing about java  

   }

      

   }
3. 
   

   // this code practise i will use .equals mehtode

   
   

   public class string3 {

       public static void main(String[] args) {

   
   

           String a = "rakesh";

           String b = new String("rakesh");

           String c = new String("RAKESH");

           System.out.println(a==b);

           // this is statement false because one string is only

           // heap memory and one string is scp so never would be same

   
   
   

           System.out.println(a.equals(b));

           // this statement is true because i am using equels methode

           // here no matter refrence here matter only value

   
   
   
   

           System.out.println(b.equalsIgnoreCase(c));

           // this statement is true because here i am

           // using equalsIgnoreCase methode and if i use

           // only .equal mehode so here bollean out is false

          

       }

      

   }
4. 
   
   

   //something inbield methode on java

   public class string4 {

       public static void main(String[] args) {

           String rakesh = "Rakesh";

           //methode of convert to uper case

           System.out.println(rakesh.toUpperCase());

           //methode of convert lower case

           System.out.println(rakesh.toLowerCase());

           //find lenght of string

           System.out.println(rakesh.length());

           // how to get character using index number

           System.out.println(rakesh.charAt(4));

           //using concat methode add string one thing this is not change of string only add

           System.out.println(rakesh.concat("Gupta"));

           //replace of string variable name not changes in the string

           rakesh = rakesh.concat("kumar");

           System.out.println(rakesh);

          

       }

      

   }
5.  

   //introduction of mutable string using string buffer

   
   

   public class string5 {

       public static void main(String[] args) {

           StringBuffer rakesh = new StringBuffer("Rakesh");

           rakesh.append("Gupta");

           System.out.println(rakesh);

       }

      

   }

   
   

   //ouput is " RakeshGupta " and remember one thing

   //this opration perfome same object refrance
6. //introduction of mutable string using string builder

   
   

   public class string6 {

       public static void main(String[] args) {

           StringBuilder rakesh = new StringBuilder("Rakesh");

           rakesh.append("Gupta");

           System.out.println(rakesh);

       }

      

   }

   
   

   //ouput is " RakeshGupta " and remember one thing

   //this opration perfome same object refrance

   //stringbuilder and and stringbuffer isn't same we leaen in multithreading

   //follow this java blog
7. 
   
   

   // we are use final keyword for string

   public class string7 {

       public static void main(String[] args) {

           //when we are use final keyword so only effect on refrance

           //here not change beacause we are use strinbuffer/stringbuilder

           final StringBuffer rakesh = new StringBuffer("rakesh");

           rakesh.append( "Gupta");

           System.out.println(rakesh);

           // but this statement is not valid beacause we are try to change

           // create new variable adress so this is always false

   
   

           // rakesh= new StringBuffer("Sony");

           System.out.println(rakesh);

   
   

           String rakesh1 = new String("amit");

           rakesh1 = new String("Rahul");

           System.out.println(rakesh1);

           // but when use final keyword its not working because

           // we are try to change variable adrees and using final keyword

           // its not possible

            final String rakesh2 = new String("preeti");

           rakesh1 = new String("farhat");

           System.out.println(rakesh2);

           //here are not changes kepp try to changes apply this code on codeeditor

       }

      

   }