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Well, if you hold a reference to the same dataset instance all the time, then you will run into trouble. But for reporting needs, you usually create a new dataset based on data from a database or so each time you run a report. And if you have a long running global object, then well, you may have to ...

You are always free to sort your dataset in anyway you want *before* you provide it to JFreeChart. Otherwise: Implement a dataset that maintains the order you want. Datasets are interfaces and the classes shipped with JFreeChart are just one possible implementation.

... and did you include jcommon as well?

There is none. A ECCN is a US invention, and as JFreeChart is not developed by a US-company, applying for a ECCN makes no sense at all (at least for us European developers .

If you need a ECCN for any version, then you would have to do the bureaucratic act on your own.

If you define no font explicitly, then the Chart will use one of the logical fonts. JDK contains a mapping between logical font names and physical font names, so for rendering text, the JDK then looks up the appropriate physical to be used. Therefore the text-display heavily depends on whether your ...

Does the IDE have it's own classpath, independent of the PC environment variable? Of course it has. How else would the IDE be able to support working with multiple projects running with possibly incompatible JAR files? IDEs usually only generate JAR files for the classes edited in them. They do not...

Do you close the streams? If you do not close the streams, then data might still sit in buffers and until you close your program, the streams will not be closes and pending data will not be written to disk.

No, ANT is only required if you want to use the provided ant-scripts to rebuild the jfreechart-jar files. For ordinary development, the pre-built jar files and/or the sources should be fully sufficient.

Well, along with the JDK, you also need to install ANT.

http://ant.apache.org/

JFreeChart's datasources are interfaces, so only your imagination and your java-compiler define the limits on what you can do with JFreeChart.

Well, not fully true: RTF *can* contain images - but it is a mess. An easy way to create RTF-documents is to use iText to build up your document and to include AWT-images in the document. So: (1) Create images from your charts (2) Create the iText-document and insert the images there. (3) Save the d...

Enable the headless mode. The NPE comes from deep inside the AWT, and is not caused by any JFreeChart code. The headless mode is available on JDK 1.4 or higher and allows you to run code that generates graphics in a server environment. The AWT should never expose NullPointerExceptions to the user, s...

Without a stacktrace it is really hard to tell what failed.

Have you enabled the HEADLESS mode?
@See FAQ for details

In that case, add two functions instead of one. (Or in JFreeChart speech: Use two series instead of just one.) A function is defined as a mapping between some input values into a single output value. There is no way how you could draw a circle under these conditions. However, in geometry, if you wan...