Skip to main content

Q) Explain about New state in thread life cycle?

A)
->when a thread class instance is created by instantiating java.long.Thread class or its user defined sub class.
->the thread is said to be in new state.
Ex:
     1) Thread t1 = new Thread ( Runnable object);
     2) MyThread t2 = new Mythread();
->in example (1) directly the thread object is created but
->in example (2) MyThread class is extends Thread class and the object is created.
For example (2) i.e.
                     class MyThread extends Thread
{
            MyThread t2 = =new MyThread();
}
For example (1) i.e.
                    class A implements Runnable
                        {
}
                    class B implements Runnable
                        {
}
                    class My-Thread extends Thread
                        {
                                    Thread t1 = new Thread(new A());
                                    Thread t2 = new Thread(new B());
                                    MyThread t3 = new MyThread();
}
Note:
->t1,t2,t3 are in new state, here
->t1,t2 are created Thread object directly but the Thread constructor taken arguments as Runnable instance but for Runnable interface we can’t create object. So, its child class object is sending as Runnable reference as argument for constructor of Thread while object created statement.
->when a Thread is in new state, body is not attached to it.

Note:
->task performing code placed directly or indirectly in the run method is nothing but the body of the Thread.
->A Thread does not have body in new state, it doesn’t compete for CPU cycles.
->so, in new state object is created but body of thread is not linked to thread.

Comments

Popular posts from this blog

Q) Explain repeated deletion of records.

A) //RepeatedDeletion.java import java.util.Scanner; import java.sql.*; class RepeatedDeletion {        public static void main(String[] args) {               Connection con= DriverManager. getConnection ( "jdbc:odbc:prince" , "scott" , "tiger" );               PreparedStatement ps=con.PreparedStatement( "DELETE FROM ACCOUNT WHERE ACCNO=?" );               Scanner s= new Scanner(System. in );               while ( true )               {                      System. out .println( "Enter accno : " );      ...

Q) Retrieving data from database?

A)   ->to retrieve the data from database we need to submit SELECT statement from JDBC application. -> executeQuery() method of statement object is used for this purpose. This method has the fallowing ResultSet executeQuery(String sql) throws SQLException Ex: ResultSet rs = st.executeQuery(“SELECT * FROM ACCOUNT”); ->objectoriented representation of tables formate data is called ResultSet object. Ao the driver created one object i.e. ResultSet object. ->object orientation representation of a table of records returned from db is nothing but “ ResultSet ” object.  

Q) What is the purpose of JDBC?

A) -> Java application can do any task by making a method (function) call. ->java method calls are not understandable to database management system. They can understand only SQL statements. ->SQL statements can’t be directly used in a java application. Java compiler complains. ->therefore, we say that java environment and database environment are heterogeneous to each other. Purpose of JDBC: ->for any kind of java application to communicate with any kind of database (management system) in a standard manner, JDBC is used.