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Set the JAVA_HOME and PATH environment variables to a given path

Source: R/java_env.R
java_env_set.Rd

Sets the JAVA_HOME and PATH environment variables for command-line Java tools and rJava initialization. See details for important information about rJava timing.

Usage

java_env_set(
  where = c("session", "both", "project"),
  java_home,
  project_path = NULL,
  quiet = FALSE
)

Arguments

where

Where to set the JAVA_HOME: "session", "project", or "both". Defaults to "session" and only updates the paths in the current R session. When "both" or "project" is selected, the function updates the .Rprofile file in the project directory to set the JAVA_HOME and PATH environment variables at the start of the R session.

java_home

The path to the desired JAVA_HOME.

project_path

A character vector of length 1 containing the project directory where Java should be installed. If not specified or NULL, defaults to the current working directory.

quiet

A logical value indicating whether to suppress messages. Can be TRUE or FALSE.

Value

Nothing. Sets the JAVA_HOME and PATH environment variables.

Additional Details

To use a different Java version with rJava-dependent packages, you must:

  1. Set JAVA_HOME using this function BEFORE loading rJava or any package that imports it

  2. Restart your R session if you already loaded rJava with the wrong Java version

rJava Path-Locking

Important for rJava Users: This function sets environment variables (JAVA_HOME, PATH) that affect both command-line Java tools and rJava initialization. However, due to rJava's path-locking behavior when .jinit is called (see https://github.com/s-u/rJava/issues/25, https://github.com/s-u/rJava/issues/249, and https://github.com/s-u/rJava/issues/334), this function must be called BEFORE .jinit is invoked. Once .jinit initializes, the Java version is locked for that R session and cannot be changed without restarting R.

.jinit is invoked (and Java locked) when you:

  • Explicitly call library(rJava)

  • Load any package that imports rJava (which auto-loads it as a dependency)

  • Even just use IDE autocomplete with rJava:: (this triggers initialization!)

  • Call any rJava-dependent function

Once any of these happen, the Java version used by rJava for that session is locked in. For command-line Java tools that don't use rJava, this function can be called at any time to switch Java versions for subsequent system calls.

Examples

if (FALSE) { # \dontrun{
# download, install Java 17
java_17_distrib <- java_download(version = "17", temp_dir = TRUE)
java_home <- java_install(
  java_distrib_path = java_17_distrib,
  project_path = tempdir(),
  autoset_java_env = FALSE
)

# now manually set the JAVA_HOME and PATH environment variables in current session
java_env_set(
  where = "session",
  java_home = java_home
)

# or set JAVA_HOME and PATH in the spefific projects' .Rprofile
java_env_set(
  where = "project",
  java_home = java_home,
  project_path = tempdir()
)

} # }