mdahlman

I confirm that OLAP is not available in the Jaspersoft BI for AWS offering. For a point-by-point list of differences between the offerings, refer to this page:
https://www.jaspersoft.com/editions
To have OLAP features you would need Jaspersoft BI Enterprise, which you could run on EC2 or on premises (or whereever you like).

Right-click the report unit and choose "New".
From there it will be obvious. (But I understand why you wouldn't think of it at first.) It a different way to think of things, but I think the new flow is better once you're used to it.
EDIT: Based on baumgaro's comment, it's clearly not as obvious as I claimed. But you need to choose "Link" when your goal is to link to an existing input control (or link to another type of object).

It could be a problem with the chart theme setting labels.
Try setting the label to "null" without the quotes. That may give the results you're looking for.

I would try something like this:
( $F{Field1}.getTime() == $F{Field2}.getTime() ) ? "some string" : "another string"
Note that your current example is closer to this:
( some comparison ) ? "some string" : some_date
That's bound to cause problems. Decide if you really want a String or if you really want a Date after the comparison is made.

Can Jaspersoft Studio support HDFS as a data source?
No.
who can tell me?
Me.
But... as Massimo mentions, there is a built-in connector for Hadoop Hive. Hive converts a SQL query into a map reduce job which uses HDFS files as its source. In many cases this is a better solution; it's far more flexible. In this case we could say the answer is "Yes", but it imposes the constraint of using Hive.
Also, I have seen custom data adapters for file data sources. These included files accessed via NTFS, Samba, HDFS, and others. So it's certainly possible to achieve this. Perhaps it will become a standard built-in data source for Jaspersoft Studio and JasperReports Server someday.
Also, Jaspersoft ETL has connectors for HDFS. So you can use this to get files from HDFS and put them somewhere else (local file system, database, etc.) for use by Jaspersoft Studio. (It works in the reverse direction for loading data into HDFS as well.)

Normally it's best to start with iReport. I'm not sure why that connection is not working.
Once that's working, then you can get the connection setup in JasperReports Server. The steps needed are listed here:
http://community.jaspersoft.com/wiki/cassandra
http://community.jaspersoft.com/wiki/jaspersoft-cassandra-jrs
A few links were broken and items mangled in the move to the new community website yesterday. But we're looking into them. Basically, you just unzip that zip file and copy everyting into the JRS directory. Match folders with the same names so you get a new file in bundles and several .jars in the lib directory. (The one you mention is necessary but insufficient.) You also need to remove the the Hive jar files because of a Thrift conflict. I swear that info was on the wiki page... but I don't see it now. To be precise, here's how I "remove" the files on a Linux system.
mv WEB-INF/lib/hive-common-0.8.1.jar WEB-INF/lib/hive-common-0.8.1.ja_mv WEB-INF/lib/hive-exec-0.8.1.jar WEB-INF/lib/hive-exec-0.8.1.ja_mv WEB-INF/lib/hive-jdbc-0.8.1.jar WEB-INF/lib/hive-jdbc-0.8.1.ja_mv WEB-INF/lib/hive-metastore-0.8.1.jar WEB-INF/lib/hive-metastore-0.8.1.ja_mv WEB-INF/lib/hive-service-0.8.1.jar WEB-INF/lib/hive-service-0.8.1.ja_

Magnus,
I haven't been on the JR forum to know if you discussed this topic there. But I just got the JR 4.0.1 release notification. It adds:
"custom property "net.sf.jasperreports.export.html.class" added at element level to allow 
specifying the CSS "class" attribute for elements when exported to HTML and XHTML/CSS format;"
As far as I can tell, this is precisely what you're looking for.
Regards,
Matt

Matt,
I think these are the lines you want in <tomcat>/webapps/jasperserver-pro/WEB-INF/log4j.properties:
log4j.logger.com.jaspersoft.commons.semantic.datasource.impl.SemanticLayerSecurityResolverImpl=DEBUGlog4j.logger.com.jaspersoft.commons.semantic.dsimpl.JdbcTableDataSet=DEBUGlog4j.logger.com.jaspersoft.commons.util.JSControlledJdbcQueryExecuter=DEBUGlog4j.logger.net.sf.jasperreports.engine.query.JRJdbcQueryExecuter=DEBUGlog4j.logger.com.jaspersoft.commons.semantic.dsimpl.JdbcBaseDataSet=DEBUG
You will need to restart JasperServer.
Alternatively/additionally, you can add these same settings using the super-secret log_settings.html page. It's an undocumented feature that might go away or change radically. But for quick tests it's great. Navigate here after logging in as superuser:
http://localhost:8080/jasperserver-pro/log_settings.html
Regards,
Matt