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Resolve path to specific Java version

Source: R/java_resolve.R
java_resolve.Rd

Finds or installs Java and returns the path to JAVA_HOME. This function does not modify any environment variables.

Usage

java_resolve(
  version = NULL,
  type = c("exact", "min"),
  distribution = "Corretto",
  backend = getOption("rJavaEnv.backend", "native"),
  install = TRUE,
  accept_system_java = TRUE,
  quiet = FALSE,
  cache_path = getOption("rJavaEnv.cache_path"),
  platform = platform_detect()$os,
  arch = platform_detect()$arch,
  .use_cache = FALSE
)

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").

type

Character. "exact" (default) checks for exact version match. "min" checks for version >= version.

distribution

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

backend

Download backend to use. One of "native" (vendor APIs) or "sdkman". Defaults to "native". Can also be set globally via options(rJavaEnv.backend = "sdkman").

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.

cache_path

The destination directory to download the Java distribution to. Defaults to a user-specific data directory.

platform

The platform for which to download the Java distribution. Defaults to the current platform.

arch

The architecture for which to download the Java distribution. Defaults to the current architecture.

.use_cache

A logical value controlling caching behavior. If FALSE (default), performs a fresh check each time (safe, reflects current state). If TRUE, uses session-scoped cached results for performance in loops or repeated calls.

Caching Behavior:

  • Session-scoped: Cache is cleared when R restarts

  • Key-based for version checks: Changes to JAVA_HOME create new cache entries

  • System-wide for scanning: Always recalculates current default Java

Performance Benefits:

  • First call: ~37-209ms (depending on operation)

  • Cached calls: <1ms

  • Prevents 30-100ms delays on every call in performance-critical code

When to Enable:

  • Package initialization code (.onLoad or similar)

  • Loops calling the same function multiple times

  • Performance-critical paths with frequent version checks

When to Keep Default (FALSE):

  • Interactive use (one-off checks)

  • When you need current data reflecting recent Java installations

  • General-purpose function calls that aren't time-critical

Value

Character string (Path to JAVA_HOME)

Examples

# \donttest{
# Get path to Java 21 (installing if necessary)
path <- java_resolve(version = 21, install = TRUE)
#> ℹ Checking system for existing Java installations...
#> ✔ Found valid system Java 21 at /usr/lib/jvm/java-21-openjdk-amd64
# }