Skip to main content

Q) What are “commandline arguments”? Explain.




A)
->during program execution values (literals) supplied from the commandline to the main method are known as commandline arguments.
->commandline arguments supplied are stored in the string array which is the parameter of JVM understandable main method.
Ex:

class commandlineexample {

       public static void main(String[] args) {
              System.out.println(args[0]);
              for(inti=0;i<args.length;i++)
                     System.out.println(args[i]);

       }

}

Note:
->to supply set of values at different times of java application execution without the need of changing the source code, commandline arguments are used.
->different file names, url, user names and passwords are supplied from the commandline in general.

Comments

Popular posts from this blog

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) 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) 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.