'java ClassNotFoundException for org.h2.Driver

I am trying to use H2 to connect to a database in Java (using Eclipse as the IDE). The sample does (below) throws a ClassNotFoundException. The thing is, I did add the h2 jar file to the system CLASSPATH. I have even checked it's there several times via printenv in the console. Am I omitting a step?

CODE:

import java.sql.*;

public class Program {

 /**
  * @param args
  */
 public static void main(String[] args) 
  throws Exception{

  try{
   System.out.println("hello, world!");
   Class.forName("org.h2.Driver");
   Connection conn = DriverManager.getConnection("jdbc:h2:~/testdb", "sa", "");
   // add application code here
   conn.close();
  }catch(ClassNotFoundException ex){
   System.out.println( "ERROR: Class not found: " + ex.getMessage() );

  }
  System.exit(0);

 }

}
javajdbch2classnotfoundexception


Solution 1:[1]

In my case (unrelated a bit, but worth mentioning), I added this to my maven pom, and the error message went away:

  <dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>xxx</version> <!-- ex: 1.2.140 -->
  </dependency>

or if you are only using h2 during unit testing:

  <dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>xxx</version> <!-- ex: 1.2.140 -->
    <scope>test</scope>
  </dependency>

Solution 2:[2]

Recently I encountered the java.lang.ClassNotFoundException: org.h2.Driver exception in IntelliJ IDEA 2017.2 EAP while using the latest version (1.4.196) of H2 driver. The solution was to downgrade to 1.4.195 that worked.

<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <version>1.4.195</version>
    <scope>test</scope>
</dependency>

Solution 3:[3]

I was having the following error (using Intellij)

java ClassNotFoundException for org.h2.Driver

Solved it by removing the scope from my pom.

was:

    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.4.197</version>
        <scope>test</scope>
    </dependency>

changed to:

    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.4.197</version>
    </dependency>

This type of error will come when we are implementing Maven Quickstart project as a dependency to another project. Mostly occurs as test only for junit. So in application it will not work.

Solution 4:[4]

The sample does (below) throws a ClassNotFoundException

Then the driver is not on the classpath.

The thing is, I did add the h2 jar file to the system CLASSPATH. I have even checked it's there several times via 'printenv' in the console.

How did you do that exactly? Please show the obtained output.

Am I omitting a step?

I can't say with the provided informations. But relying on the CLASSPATH environment variable is a bad practice anyway and you should use the -cp option if you're running Java on the command line. Like this:

java -cp h2.jar com.acme.Program

Is there a way I can set Eclipse to use the jar file when I use the RUN menu so that I don't have to run from the Console all the time?

Yes. Under Eclipse, add the JAR to the project build path: right-click on your project then Properties > Java Build Path > Libaries > Add JARS... (assuming the H2 JAR is available in a directory relative to your project). Others IDE have equivalent way of doing this.

Solution 5:[5]

In my case(I use sbt) change

libraryDependencies += "com.h2database" % "h2" % "1.4.196" % Test

to

libraryDependencies += "com.h2database" % "h2" % "1.4.196"

Solution 6:[6]

If you use Gradle change dependency in build.gradle: 

testCompile group: 'com.h2database', name: 'h2', version: '1.4.199'

to

compile group: 'com.h2database', name: 'h2', version: '1.4.199'

Solution 7:[7]

The <scope>[database_name]</scope> should include the database you are working with. If you change your db from one to another, make sure to change the scope also. As soon as i changed it the error went away.

Solution 8:[8]

Use release version.

    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>RELEASE</version>
        <scope>compile</scope>
    </dependency>

Solution 9:[9]

In my case it's actually the connection string issue. I saw this.

After I added the mem in the URL string below, and it worked.

String url = "jdbc:h2:mem:~/test";

Solution 10:[10]

Using <scope>test</scope> should not work logically. try it with <scope>runtime</scope> or <scope>provided</scope>, unless you need it only for testing phase.

On maven docs, it says that <scope>test</scope> dependency is not required for normal use of the application, and is only available for the test compilation and execution phases
https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html

Solution 11:[11]

I have faced same issue when using : 2 times in h2 database, because Driver manager can not identify proper connection type

  • when you use "jdbc:h2:localhost:123/db", then it divide into "jdbc","h2:localhost","123/db",
  • so here expected value is h2 but getting h2:localhost because of issue in core regex for identify driver class from list of loaded drivers

Use full path like:

  • Don't: "jdbc:h2:testdb",         Do:"jdbc:h2:/c:/.../testdb"
  • Don't: "jdbc:h2:localhost:123/db",    Do: "jdbc:h2://localhost:123/db"

Solution 12:[12]

I am working with intelliJ. I had the "h2-1.4.200" in the lib folder. I tried every suggestion, ranging from , to . Strangely, my problem got solved only by going to these places : Project Structure -> Artifact -> Output Layout -> Available Elements and then expanding the content of the folder and then right click on "h2-1.4.200" and finally select "Extract Into Output Root". :) The strange solution

Solution 13:[13]

I use sbt. In build.sbt, I removed the "h2" dependency and included this instead: "com.h2.database" % "h2" % "1.4.200" And it worked!

Solution 14:[14]

This worked with testRuntimeOnly 'com.h2database:h2:1.4.200'

and in application.yaml property remove or comment out # driverClassName: org:h2:Driver

As per springboot latest documentation jdbc driver is not required as it is automatically detected.

Solution 15:[15]

Remove the scope tag

<scope>test</scope>

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