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Execute rJava code in a separate process with specific Java version

Source: R/java_scoped.R
with_rjava_env.Rd

Runs the provided function in a fresh R subprocess where rJava has not yet been loaded. This allows you to enforce a specific Java version for rJava operations without affecting the main R session or requiring a restart.

Usage

with_rjava_env(
  version,
  func,
  args = list(),
  distribution = "Corretto",
  install = TRUE,
  accept_system_java = TRUE,
  quiet = TRUE,
  libpath = .libPaths()
)

Arguments

version

Java version specification. Accepts:

  • Major version (e.g., 21, 17): Downloads the latest release for that major version.

  • Specific version (e.g., "21.0.9", "11.0.29"): Downloads the exact version.

  • SDKMAN identifier (e.g., "25.0.1-amzn", "24.0.2-open"): Uses the SDKMAN backend automatically. When an identifier is detected, the distribution and backend arguments are ignored and derived from the identifier. Find available identifiers in the identifier column of java_list_available(backend = "sdkman").

func

The function to execute in the subprocess.

args

A list of arguments to pass to func.

distribution

Character. The Java distribution to download. Defaults to "Corretto". Ignored if version is a SDKMAN identifier.

install

Logical. If TRUE (default), attempts to download/install if missing. If FALSE, returns FALSE if the version is not found.

accept_system_java

Logical. If TRUE (default), the function will scan the system for existing Java installations (using JAVA_HOME, PATH, and OS-specific locations). If a system Java matching the version and type requirements is found, it will be used. Set to FALSE to ignore system installations and strictly use an rJavaEnv managed version.

quiet

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

libpath

Optional character vector of library paths to use in the subprocess. Defaults to .libPaths().

Value

The result of func.

Details

This function requires the callr package.

Examples

# \donttest{
# Run a function using Java 21 in a subprocess
result <- with_rjava_env(
  version = 21,
  func = function(x) {
    library(rJava)
    .jinit()
    .jcall("java.lang.System", "S", "getProperty", "java.version")
  },
  args = list(x = 1)
)
print(result)
#> [1] "21.0.10"
# }