Skip to main content

Q) What is “message passing” what is the purpose of message passing?




A)
->in an object oriented system objects communicate one another through message passing.
->in implementation of message passing the fallowing things are involved

1)      message sender (object)
2)      message receiver (object)
3)      message (method)
->Calling method belongs to which object that object is the message sender. Called method belongs to the object. That object is the message receiver.
->One object calling a method from another object is nothing but the first object is sending a message to the second object.

Ex:
class A
{
       void x()
       {
              B b=new B();
              b.y();//message passing
       }
}
class B
{
       void y()
       {
             
       }
}

->in the above example, object of class A is the message sender and the object of class B is the message receiver. Method call y is nothing but message passing.
->whenever one object needs the service of another object it communicates with that object using message passing.
->message sender object is service request object and message receiver object is the service provider object.

Comments

Post a Comment

Popular posts from this blog

Q) What is JDBC driver? What is its role in java database connection?

A) ->A translation software written in java according o JDBC specification is nothing but “JDBC driver”. -> JDBC driver implements JDBC API. Use single API. JDBC driver role: They are 4 roles   1)       Establishing connection between JDBC client and database server. 2)       Receiving JDBC method calls made by JDBC client while performing database (CRUD) operations. 3)       Translating java method calls into DBMS understandable calls and forwarding them to database server. 4)       Receiving the results from database server. Translating them into java format and handling over the same to the JDBC client.
Post a Comment
Read more

Q) What is ODBC?

A) ->open database connectivity is a technology from MS that enables any language program (other than java) to communication with database Management System. ->in java program ODBC is directly not allowed for the fallowing reasons 1) OS dependency 2) Procedural oriented approach 3) Security thread
Post a Comment
Read more

Q) Explain about nested classes?

A) ->defining a class with in another class is known as nesting of the class. Ex: class A {        class B        {                      } //nested class, and inner class.because it is not static class. } //enclosing class or outer class. ->static class is declared in inside an another class then it does not become an inner class. Note: non-static nested class is known as “inner class”. In the above example class B is nested but not an inner class. Ex: class D {        static c        {                      } //nested class, but not an inner class , because of static class. } //outer class. ->we have three different kinds of inner classes. 1) Member inner class 2) Meth...
Post a Comment
Read more