Apart from downloading GpsPrune, there are other pieces of software you may need to install if you haven't got them already. The only one you need to have in order for GpsPrune to work is the Java Runtime, all the others are optional, but you may want to get them in order to get access to some of GpsPrune's functionality.
Note that if you get GpsPrune from a package manager (such as those in Debian or Ubuntu), then often all these dependencies will be automatically downloaded and installed for you. Full details are given in the download page.
The only required software is a java runtime, also known as a JRE (Java runtime environment). To run GpsPrune you need to get a java runtime of at least version 8, but version 11 is fairly standard now and newer versions also work fine. If you haven't got a java runtime already then it's best to get the latest version available to make sure all the security fixes have been applied.
To install on Linux, simply get it from your package manager. Almost all current distributions now offer OpenJDK (instead of the old Sun JDK), for example Debian's runtime package is called openjdk-11-jre with several other related packages including the JDK itself, openjdk-11-jdk. These packages can be simply installed either from the command line or from GUI tools such as synaptic or "Software Manager".
For Windows, go to java.net's JDK 17 download page, or go through the confusing variety of options available at the Wikipedia page for OpenJDK.
Mac OSX users apparently get prompted to install a java runtime the first time they try to run a java program. Just accept the prompts and it will be installed for you.
The java3d libraries are used for the real-time 3d display in GpsPrune. They are optional, but recommended if you want to use either the interactive 3d display or the povray export. According to wikipedia there are now two versions of Java3d to choose from: either the version 1.5.2 which is several years old now and used to be available from java3d.java.net, or the newer (forked?) version 1.6 from a group called Jogamp (but which is described by java3d.org as "may still be a bit buggy").
To install either version manually, you need to download the jars / zips / 7z files, and follow the instructions to unpack the contents in the correct way so that they can be found by your java installation. If you have Debian or Ubuntu you can get the libjava3d-java package from the normal repositories, which currently all still contain the 1.5.2 version.
Again, Mac OSX users don't have to do anything here because apparently it is installed already by default. You can check this using the "About" page in GpsPrune.
Note that these java3d libraries are optional for running GpsPrune, but if you want to build the complete source, you'll need to have the java3d libraries installed so that you can build everything.
If anyone has had any success at all with jogamp's 1.6 or 1.7 versions, even just getting their demo applications to run, please get in touch. When after 8 years it's still described as 'new' and 'still buggy' and there still isn't even a proper home page for java3d, I wonder whether it's even usable. I tried to get their basic demo to work but failed completely. Something about a gluegen not being able to find a newt. For now I'd recommend using 1.5.2, although I'd love to hear from anybody who managed to get a later version working.
Exiftool is a multi-purpose tool for handling the exif data inside jpeg files. GpsPrune uses it to save the coordinates into the Jpeg files after correlation. If you haven't got Exiftool you can still read the coordinates from Jpegs and still generate Kmz files containing the photos in the right place but GpsPrune won't be able to save those coordinates in the Jpeg files.
To install on Linux, use your package manager. For example, on Mandriva just type urpmi exiftool, for Debian or Ubuntu aptitude install libimage-exiftool-perl.
To install on Windows, go to exiftool.org and select the appropriate download file. You'll probably want the executable version which doesn't assume that you've already got perl. Open this file with an unzip tool and extract the single file called exiftool(k).exe. Now you need to rename this file exiftool.exe and either move it to somewhere within the system path or extend the system path to include the directory where you saved this exe. See the install instructions for more details.
To install on Mac, again go to sno.phy.queensu.ca/~phil/exiftool and download the Mac package, then install this in the usual way. Or you could use macports (the command is port install p5-image-exiftool I think) or Fink (apt-get install image-exiftool-pm I think).
Gpsbabel is a command-line tool for converting between data formats. GpsPrune uses it to load data directly from GPS receivers, and also to send data back to the GPS receivers. If you don't have gpsbabel installed then these functions won't be available.
To install on Linux, use your package manager. For example, on Mandriva just type urpmi gpsbabel, for Debian or Ubuntu aptitude install gpsbabel.
To install on Windows, go to gpsbabel.org and select the zip file from the download page. Save this file and open it in a zip utility, then extract the file gpsbabel.exe and save it somewhere in your system path (eg the windows directory).
To install on Mac, again go to gpsbabel.org and select the dmg file for Mac. This should be installed in the usual way. Or you can get it from macports (the command is port install gpsbabel I think) or Fink (apt-get install gpsbabel I think).
Gnuplot is a powerful charting tool which GpsPrune uses to draw the charts of altitudes, times, speeds, distances and so on. If you don't have gnuplot installed then GpsPrune won't be able to generate these charts.
To install on Linux, use your package manager. For example, on Mandriva just type urpmi gnuplot, for Debian or Ubuntu aptitude install gnuplot gnuplot-x11.
To install on Windows, go to gnuplot.info and select the appropriate zip file from the binary download page. Open this file in a zip utility, then follow the installation instructions inside the zip. Also you'll need to inform GpsPrune where to find the executable (now called pgnuplot.exe), using the menu function Settings -> Set program paths.
For the Mac, there is no binary on sourceforge but you can use either macports (the command is port install gnuplot I think) or Fink (apt-get install gnuplot I think).
Povray is a rendering program for generating high-quality rendering of 3d images using the Pov files created by GpsPrune (using the menu command File -> Export POV).
To install on Linux, again you may be able to use your package manager. Just search for a package called povray which is currently at version 3.7.
To install on Windows, go to povray.org and select your download (32-bit or 64-bit) from the download page. Save this executable file, run it, and follow the installation wizard.
To install on Mac, you can use the povray download page to get the Mac version and install it as usual. Or you can get it from macports (the command is port install povray I think) or Fink (apt-get install povray I think).
JUnit is a framework for managing unit tests, so it's not used at all when GpsPrune is running, but is necessary if you want to compile and run the unit tests which help development. GpsPrune uses Junit 5 for its tests, so it won't work with versions 3 or 4. Fortunately, version 5 is included in the Eclipse IDE (and others), so it probably won't need anything else to be installed.
Again, if you only want to run GpsPrune and don't intend to compile it or make changes to the source code, then you don't need JUnit.