java interface , vector and wrapper classes смотреть онлайн

JAVA STRING BUFFER CLASS: StringBuffer is a peer class of string. While string creates string of fixed_length, StringBuffer creates strings of flexible length that can be modified in terms of both length and content.
Vectors : the generic utility functionswith variable arguments can be used to pass different arguments depending upon the calling situations.
Vector intvest = new Vector();
Vector intvest = new Vector(3);
Vector advantages :
1. Use vector to store objects
2. Used to store a list of objects
3. We can add and delete objects
Vector methods name :
1. addElement()
2. elementAt()
3. size()
4. removeElement()
5. removeAllElement()
6. copyInto(array);
7. a.insertElementAt(,)


WRAPPER CLASSES :
VECTOR CANNOT HANDLE PRIMITIVE DATATYPES LIKE THAT INT , FLOAT , LONG , CHAR AN DOUBLE. PRIMITIVE DATATYPES MAY BE CONVERTED INTO OBJECT TYPES BY USING WRAPPER CLASS.


INTERFACE : MULTIPLE INHERITENCE
DEFINING INTERFACE: INTERFACE CONTAIN METHODS AND VARIABLES BUT with a major difference. Interface define only abstract methods and final fields
Interface item
{
static final int code = 1001;
static final String name = “Sachin”;
void display();
}
extends interface : interface and subinterface inherit all the members of the superinterface. Extends keywords.
Interface item
{
static final int code = 1001;
static final String name = “Sachin”;
} interface itemmethods
{ void display(); }
Interface item extends itemmethods
{……}
Accessing interface variablesAccessing interface variables