H2 database User defined java function Class not found

Question

When I create an ALIAS for registering the java function in the H2 database, it gives error of class not found. I am running the h2 database on a tcp connection.

sample,

public class TimeFrame { 
    public static void main(String... args) throws Exception {
        Class.forName("org.h2.Driver");
        Connection conn = DriverManager.getConnection("jdbc:h2:tcp://MYIP:9092/~/test", "sa", "");
        Statement stat = conn.createStatement();

        //Setup Table
        stat.execute("DROP TABLE IF EXISTS timeframe");
        stat.execute("CREATE TABLE timeframe (last_updated TIMESTAMP, ip int");
        stat.execute("CREATE ALIAS IF NOT EXISTS SLIDEWINDOW FOR \"h2TimeFrame.TimeFrame.slidewindow\" ");
    }
}

This is all in pacakge name: h2TimeFrame. To test,

take the sample class "Function" from the org.h2.samples package. how would you run this class on the server with TCP connection. Changing

  Connection conn = DriverManager.getConnection("jdbc:h2:~/test", "sa", "");

to

  Connection conn = DriverManager.getConnection("jdbc:h2:tcp://IPADDRESS:9092/~/test", "sa", "");

Take the sample class "Function" from the org.h2.samples package. how would you run this class on the server with TCP connection. Changing Connection conn = DriverManager.getConnection("jdbc:h2:~/test", "sa", ""); to Connection conn = DriverManager.getConnection("jdbc:h2:tcp://IPADDRESS:9092/~/test", "sa", ""); — UserBSS1
– UserBSS1, Commented Sep 23, 2013 at 16:38

Java Devil · Accepted Answer · 2013-09-19 21:09:02Z

1

Make sure that:

The class is public
The method is public and static
The class must be available in the classpath of the database engine

From H2 Docs:

When referencing a method, the class must already be compiled and included in the classpath where the database is running. Only static Java methods are supported; both the class and the method must be public

answered Sep 19, 2013 at 21:09

Java Devil

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3 Comments

Thomas Mueller Over a year ago

Yes. "in the classpath of the database engine" in this case means it has to be in the classpath of the server (in the process / JVM where the database server is running)

Thomas Mueller Over a year ago

It might be simpler to declare the user defined function is defined as source code. That way it is automatically available on the server.

UserBSS1 Over a year ago

@javadevil, I did made sure about the 3 things u mentioned and they are also in the documentation. But, didnt worked. For the above given sample class (TimeFrame), if I make a runnable jar and include it in the classpath when starting the server (org.tools.server), should it work? as its not working! am i missing something here

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