Installation

Installation of FastRet consist of the following three steps, which are explained in detail in the following sections.

Install Java Development Kit (JDK) version 11 or higher
Use install.packages("pak") to install the R package manager pak from CRAN
Use pak::pkg_install("FastRet") to install FastRet from the GitHub repository

Install Java Development Kit (JDK)

FastRet uses the rJava package, which itself requires the Java Development Kit (JDK) version 11 or higher. You can test whether you java a sufficiently high version of JDK already installed on your system by entering the following command in your terminal.

java -version

If you do not have a suitable JDK installed, you can download and install it from various vendors such as the Adoptium Working Group or Azul. For a list of vendors providing JDKs, see whichjdk.com.

When installing a JDK, there a few things to look out for, e.g.:

Windows users should activate the update of “JavaSoft registry keys” during the installation process. This is necessary for the rJava package to find the SDK installation. Depending on the SDK vendor you choose, the option might be named differently.
macOS users must use at least R-4.1.2.
Linux users should run R CMD javareconf after installing the JDK to make sure that R can find the JDK.

Install the R package manager `pak`

This can be done by entering the following command in an R session:

install.packages("pak")

Install FastRet

To install FastRet from the GitHub repository, enter the following command in an R session:

pak::pkg_install("FastRet")

Troubleshooting

JAVA_HOME cannot be determined from the Registry

The error message JAVA_HOME cannot be determined from the Registry indicates that the rJava package cannot find the JDK installation. This can cause further errors such as ERROR: lazy loading failed for package 'FastRet' when trying to load FastRet. See rJava installation fails for possible solutions.

rJava installation fails

If the installation of the rJava package fails:

Make sure you have a suitable JDK installed on your system, as described in Install Java Development Kit (JDK).
Reinstall the rJava package by entering the following command in an R session: install.packages("rJava").
Run library("rJava") to ensure that the package can be loaded.