Jalali calendar, or solar Hijri, is calendar of Iran and
    Afghanistan (<https://en.wikipedia.org/wiki/Solar_Hijri_calendar>).
    This package is designed to working with Jalali date. For this
    purpose, It defines JalaliDate class that is similar to Date class.

Low-level interface to Java VM very much like .C/.Call and friends. Allows creation of objects, calling methods and accessing fields.

Quickly install 'Java Development Kit (JDK)' without
    administrative privileges and set environment variables in current R
    session or project to solve common issues with 'Java' environment
    management in 'R'. Recommended to users of 'Java'/'rJava'-dependent
    'R' packages such as 'r5r', 'opentripplanner', 'xlsx', 'openNLP',
    'rWeka', 'RJDBC', 'tabulapdf', and many more. 'rJavaEnv' prevents
    common problems like 'Java' not found, 'Java' version conflicts,
    missing 'Java' installations, and the inability to install 'Java' due
    to lack of administrative privileges.  'rJavaEnv' automates the
    download, installation, and setup of the 'Java' on a per-project basis
    by setting the relevant 'JAVA_HOME' in the current 'R' session or the
    current working directory (via '.Rprofile', with the user's consent).
    Similar to what 'renv' does for 'R' packages, 'rJavaEnv' allows
    different 'Java' versions to be used across different projects, but
    can also be configured to allow multiple versions within the same
    project (e.g.  with the help of 'targets' package). Note: there are a
    few extra steps for 'Linux' users, who don't have any 'Java'
    previously installed in their system, and who prefer package
    installation from source, rather then installing binaries from 'Posit
    Package Manager'. See documentation for details.

The RJDBC package is an implementation of R's DBI interface using JDBC as a back-end. This allows R to connect to any DBMS that has a JDBC driver.

Interface around 'JDemetra+' (<https://github.com/jdemetra/jdemetra-app>), the seasonal adjustment software officially
    recommended to the members of the European Statistical System (ESS) and the European System of Central Banks.
    It offers full access to all options and outputs of 'JDemetra+', including the two leading seasonal adjustment methods
    TRAMO/SEATS+ and X-12ARIMA/X-13ARIMA-SEATS.