Difference between Type 1, 2, 3 and 4 JDBC Driver in Java?

One of the oldest Java interview question is what is difference between different types of JDBC drivers e.g. what is difference between type 1, type 2, type 3 or type 4 drivers? Sometime also asked as how do you choose between different JDBC driver? When to use type 3 over type 4 driver etc. Its 2015 now and I doubt anyone is using JDBC driver other than type 4 for connecting to database, but let's see how to answer this question when you face it during interview. Difference between different types of JDBC driver comes from the fact how they work, which is basically driven by two factor, portability and performance. Type 1 JDBC driver is the poorest in terms of portability and performance, while type 4 JDBC driver is highly portable and gives best performance. You will learn more differences between different JDBC drivers as we go along. Since database is very important and almost all Java application uses database in some form or other, its important to learn JDBC well. If you are a beginner started to learn Java and struggling with JDBC then I suggest you to take a look at Practical Database Programming with Java By Ying Bai. It's one of the rarest book, which covers Java database connectivity well,

Read more »

How to Fix java.lang.classnotfoundexception oracle.jdbc.driver.oracledriver [Solved]

Scenario : Your Java program, either standalone or Java web application is trying to connect to Oracle database using type 4 JDBC thin driver "oracle.jdbc.driver.oracledriver", JVM is not able to find this class at runtime. This JAR comes in ojdbc6.jar or ojdbc6_g.jar which is most probably not available in classpath.

Cause : When you connect to Oracle database from Java program, your program loads the implementation of Driver interface provided by the database vendor using class.forName() method, which throws ClassNotFoundException when driver class is not found in classpath. In case of Oracle the driver implementation is oracle.jdbc.driver.oracledriver and "java.lang.classnotfoundexception oracle.jdbc.driver.oracledriver" error indicate that this class is  not available in classpath. Since this class is bundled into ojdbc6.jar, its usually the case of this JAR not present in Classpath

Read more »