Table Of Content

Introduction To Strings

• Strings is a collection of characters or a array of characters.
• It is a non-primitive datatype.
• In java Strings are treated as object because the memory is allocated in heap segment.
• Ex. "Nandan", "2" etc.....

Types Of String

1. Immutable String

• Once String object is created its data or state can't be changed but a new String object is created
• Ways Of Creating Immutable String

String s = new String("Nandan");
String s = "Nandan";
char []a ={a,b,c,d};
byte[] a={97,98,99,100};

2. Mutable String

• Those Strings whose content can be changed without creating a new object
• To create a mutable string, we can use StringBuffer and StringBuilder class. Both classes create a mutable object of string but which one we should use is totally depends on the scenario

public class MutableString
{
    public static void main (String[] args)
    {
        StringBuffer str1 = new StringBuffer("JavaGoal");
        StringBuilder str2 = new StringBuilder("Learning");
        
        System.out.println("Value of str1 before change :" + str1);
        System.out.println("Value of str2 before change :" + str2);
        
        str1.append(".com");
        str2.append(" website");
        
        System.out.println("Value of str1 after change :" + str1);
        System.out.println("Value of str2 after change :" + str2);
    }
}
//output
Value of str1 before change :JavaGoal
Value of str2 before change :Learning
Value of str1 after change :JavaGoal.com
Value of str2 after change :Learning website

Note

• Refer

Immutable String

• Once String object is created its data or state can't be changed but a new String object is created