Difference between Mutable objects and Immutable objects

Question

Any one please give the diff between Mutable objects and Immutable objects with example

User · Answer

Immutable objects are simply objects whose state (the object's data) cannot change after construction. Examples of immutable objects from the JDK include String and Integer.

For example:(Point is mutable and string immutable)

     Point myPoint = new Point( 0, 0 );
    System.out.println( myPoint );
    myPoint.setLocation( 1.0, 0.0 );
    System.out.println( myPoint );

    String myString = new String( "old String" );
    System.out.println( myString );
    myString.replaceAll( "old", "new" );
    System.out.println( myString );

The output is:

java.awt.Point[0.0, 0.0]
java.awt.Point[1.0, 0.0]
old String
old String

User · Answer

Mutable objects have fields that can be changed  immutable objects have no fields that can be changed after the object is created   A very simple immutable object is a object without any field   For example a simple Comparator Implementation    class Mutable    private int value     public Mutable int value         this value   value           getter and setter for value    class Immutable     private final int value     public Immutable int value         this value   value           only getter

User · Answer

Mutable objects can have their fields changed after construction  Immutable objects cannot   public class MutableClass     private int value    public MutableClass int aValue      value   aValue       public void setValue int aValue      value   aValue       public getValue       return value         public class ImmutableClass     private final int value      changed the constructor to say Immutable instead of mutable  public ImmutableClass  final int aValue        The value is set  Now  and forever    value   aValue       public final getValue       return value

User · Answer

They are not different from the point of view of JVM  Immutable objects don t have methods that can change the instance variables  And the instance variables are private  therefore you can t change it after you create it  A famous example would be String  You don t have methods like setString  or setCharAt  And s1   s1    w  will create a new string  with the original one abandoned  That s my understanding

User · Answer

Immutable Object s state cannot be altered    for example String   String str   abc    a object of string is created str    str    def     a new object of string is created and assigned to str

[java] Difference between Mutable objects and Immutable objects

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