Technical Interview Questions
A JDBC connection is created in auto-commit mode by default. This means that each individual SQL statement is treated as a transaction and will be automatically committed as soon as it is executed. If you require two or more statements to be grouped into a transaction then you need to disable auto-commit mode using below … Read more
Which One Will You Use Statement or PreparedStatement? Or Which One to Use When (Statement/PreparedStatement)? Compare PreparedStatement vs Statement By Java API definitions: Statement is a object used for executing a static SQL statement and returning the results it produces. PreparedStatement is a SQL statement which is precompiled and stored in a PreparedStatement object. This object can then be … Read more
Method forName() is a static method of java.lang.Class. This can be used to dynamically load a class at run-time. Class.forName() loads the class if its not already loaded. It also executes the static block of loaded class. Then this method returns an instance of the loaded class. So a call to Class.forName(‘MyClass’) is going to … Read more
This is one of the most commonly asked questions from JDBC fundamentals, and knowing all the steps of JDBC connection is important. import java.sql.*; class JDBCTest { public static void main (String args []) throws Exception { //Load driver class Class.forName (“oracle.jdbc.driver.OracleDriver”); //Create connection Connection conn = DriverManager.getConnection (“jdbc:oracle:thin:@hostname:1526:testdb”, “scott”, “tiger”); // @machineName:port:SID, userid, password Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery(“select ‘Hi’ from dual”); while (rs.next()) System.out.println (rs.getString(1)); // Print col 1 => Hi stmt.close(); } } To establish a database connection using JDBC thin driver in Core Java, you typically follow … Read more
Connection Pooling is a technique used for sharing the server resources among requested clients. It was pioneered by database vendors to allow multiple clients to share a cached set of connection objects that provides access to a database. Getting connection and disconnecting are costly operation, which affects the application performance, so we should avoid creating … Read more