JasperReports: CONCATENATE function not found

You should also add jasperreports-functions-5.2.0.jar to your classpath.

This library contains net.sf.jasperreports.functions.standard.TextFunctions class with CONCATENATE function.

You can find this artifact at http://jaspersoft.artifactoryonline.com/jaspersoft/jr-ce-releases Maven repository.

The snippet from my test pom.xml:

<repositories>
    <repository>
        <id>jr-ce-releases</id>
        <url>http://jaspersoft.artifactoryonline.com/jaspersoft/jr-ce-releases</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>net.sf.jasperreports</groupId>
        <artifactId>jasperreports</artifactId>
        <version>5.2.0</version>
    </dependency>

    <dependency>
        <groupId>org.codehaus.groovy</groupId>
        <artifactId>groovy-all</artifactId>
        <version>2.0.1</version>
    </dependency>
    <dependency>
        <groupId>net.sf.jasperreports</groupId>
        <artifactId>jasperreports-functions</artifactId>
        <version>5.2.0</version>
    </dependency>
    <dependency>
        <groupId>joda-time</groupId>
        <artifactId>joda-time</artifactId>
        <version>2.1</version>
    </dependency>
</dependencies>

The net.sf.jasperreports.jasperreports-functions:5.2.0 artifact depends on joda-time.joda-time:2.1 artifact - you should also add to classpath the joda-time-2.1.jar

Notes:

You can find more information in Custom Functions in Report Expressions article