CAMEL-23703: camel-launcher - shared Java 17+ runtime discovery for camel.sh and camel.bat

docs/user-manual/modules/ROOT/pages/camel-4x-upgrade-guide-4_22.adoc

@@ -56,6 +56,30 @@ run the CLI automatically renames a pre-existing global `~/.camel-jbang-user.pro
 `~/.camel-cli.properties` and a pre-existing local `./camel-jbang-user.properties` to
 `./camel-cli.properties`; an existing new file is never overwritten.
 
+==== Camel CLI launcher Java runtime discovery
+
+The self-contained Camel CLI launcher scripts (`bin/camel.sh` and `bin/camel.bat` in the
+`camel-launcher` distribution) now share a single Java runtime discovery contract. Candidates
+are evaluated in this fixed order, and the first one that exists, is executable, and reports a
+Java major version of at least 17 is used:
+
+1. `JAVACMD` (explicit override, unchanged).
+2. `$JAVA_HOME/bin/java` (`%JAVA_HOME%\bin\java.exe` on Windows). This is also how the SDKMAN
+   `java` candidate is honored, since SDKMAN exports `JAVA_HOME`.
+3. The first `java` (`java.exe`) found on `PATH`.
+4. `CAMEL_FALLBACK_JAVA`, a new variable set by package-manager installs when the JDK location
+   is deterministic.
+
+Candidates older than Java 17, missing, non-executable, or with unparseable version output are
+skipped. If none qualify, the launcher now exits nonzero with a diagnostic listing the checked
+sources instead of attempting to run an unsuitable Java.
+
+The obsolete macOS `JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/...` default was
+removed from `camel.sh`; set `JAVA_HOME` or `JAVACMD`, or ensure a Java 17+ `java` is on `PATH`.
+The Gentoo `java-config` auto-detection and the IBM AIX `$JAVA_HOME/jre/sh/java` probe were also
+removed; set `JAVA_HOME` or `JAVACMD` explicitly on those platforms.
+`JAVA_OPTS` handling is unchanged: when unset, the default `-Xmx512m` heap is applied.
+
 === camel-langchain4j-agent
 
 The `Agent.chat()` method return type has changed from `String` to `Result<String>` (from `dev.langchain4j.service.Result`).

dsl/camel-jbang/camel-launcher/src/main/resources/bin/camel.bat

@@ -28,45 +28,106 @@ set DIRNAME=%~dp0
 if "%DIRNAME%" == "" set DIRNAME=.
 set BASEDIR=%DIRNAME%
 
-@REM Java command to use
-if "%JAVA_HOME%" == "" goto noJavaHome
-set JAVACMD=%JAVA_HOME%\bin\java.exe
-goto checkJavaCmd
+@REM --- Shared Java 17+ discovery contract ---
+@REM Candidates in order: JAVACMD, %JAVA_HOME%\bin\java.exe, java.exe on PATH, CAMEL_FALLBACK_JAVA.
+set CAMEL_MIN_JAVA=17
 
-:noJavaHome
-set JAVACMD=java.exe
+set "CAMEL_JAVACMD="
+call :tryJava "%JAVACMD%"
+if defined CAMEL_JAVACMD goto haveJava
+if defined JAVA_HOME call :tryJava "%JAVA_HOME%\bin\java.exe"
+if defined CAMEL_JAVACMD goto haveJava
+for %%p in (java.exe) do call :tryJava "%%~$PATH:p"
+if defined CAMEL_JAVACMD goto haveJava
+call :tryJava "%CAMEL_FALLBACK_JAVA%"
+if defined CAMEL_JAVACMD goto haveJava
+goto noJava
 
-:checkJavaCmd
-if exist "%JAVACMD%" goto init
+:haveJava
+set "JAVACMD=%CAMEL_JAVACMD%"
 
-echo.
-echo Error: JAVA_HOME is not defined correctly. >&2
-echo Cannot execute "%JAVACMD%" >&2
-echo.
-goto error
-
-:init
 @REM Set JVM options if specified
 if "%JAVA_OPTS%" == "" set JAVA_OPTS=-Xmx512m
 
-@REM Find the JAR file
-dir /b "%BASEDIR%\camel-launcher-*.jar" > nul 2>&1
-if not errorlevel 1 (
-  for /f "tokens=*" %%j in ('dir /b "%BASEDIR%\camel-launcher-*.jar"') do set LAUNCHER_JAR=%BASEDIR%\%%j
-) else (
-  for %%i in ("%BASEDIR%\camel-launcher-*.jar") do set LAUNCHER_JAR=%%i
-)
+@REM Find the launcher JAR
+set "LAUNCHER_JAR="
+for %%i in ("%BASEDIR%\camel-launcher-*.jar") do set "LAUNCHER_JAR=%%i"
 
-@REM Execute Camel CLI
-"%JAVACMD%" %JAVA_OPTS% -jar "%LAUNCHER_JAR%" %*
-if ERRORLEVEL 1 goto error
-goto end
+@REM Execute Camel CLI, preserving arguments and the child exit code
+for %%e in ("%JAVACMD%") do set "_JAVACMD_EXT=%%~xe"
+if /i "%_JAVACMD_EXT%"==".bat" goto executeJavaBatch
+if /i "%_JAVACMD_EXT%"==".cmd" goto executeJavaBatch
+goto executeJavaNative
 
-:error
-set ERROR_CODE=1
+:executeJavaBatch
+call "%JAVACMD%" %JAVA_OPTS% -jar "%LAUNCHER_JAR%" %*
+set ERROR_CODE=%ERRORLEVEL%
+goto javaExecuted
 
-:end
+:executeJavaNative
+"%JAVACMD%" %JAVA_OPTS% -jar "%LAUNCHER_JAR%" %*
+set ERROR_CODE=%ERRORLEVEL%
+
+:javaExecuted
 @REM End local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" endlocal & set ERROR_CODE=%ERROR_CODE%
+exit /B %ERROR_CODE%
+
+:noJava
+echo. 1>&2
+echo Error: no suitable Java runtime found. Camel CLI requires Java %CAMEL_MIN_JAVA% or newer. 1>&2
+echo Checked: JAVACMD, %%JAVA_HOME%%\bin\java.exe, java.exe on PATH, CAMEL_FALLBACK_JAVA. 1>&2
+echo Install a Java %CAMEL_MIN_JAVA%+ runtime and set JAVA_HOME or JAVACMD, or add java.exe to PATH. 1>&2
 if "%OS%"=="Windows_NT" endlocal
+exit /B 1
 
-exit /B %ERROR_CODE%
+:tryJava
+@REM %1 = candidate path (quoted). On success sets CAMEL_JAVACMD.
+set "_CAND=%~1"
+if "%_CAND%"=="" exit /b 1
+if not exist "%_CAND%" exit /b 1
+for %%e in ("%_CAND%") do set "_CAND_EXT=%%~xe"
+set "_PROBE_DIR="
+if defined TEMP set "_PROBE_DIR=%TEMP%"
+if not defined _PROBE_DIR if defined TMP set "_PROBE_DIR=%TMP%"
+if not defined _PROBE_DIR set "_PROBE_DIR=%BASEDIR%"
+
+:tryJavaProbePath
+set "_PROBE=%_PROBE_DIR%\camel-java-probe-%RANDOM%-%RANDOM%.tmp"
+if exist "%_PROBE%" goto tryJavaProbePath
+if /i "%_CAND_EXT%"==".bat" goto tryJavaProbeBatch
+if /i "%_CAND_EXT%"==".cmd" goto tryJavaProbeBatch
+goto tryJavaProbeNative
+
+:tryJavaProbeBatch
+call "%_CAND%" -version <NUL >"%_PROBE%" 2>&1
+set "_PROBE_RC=%ERRORLEVEL%"
+goto tryJavaProbeComplete
+
+:tryJavaProbeNative
+"%_CAND%" -version <NUL >"%_PROBE%" 2>&1
+set "_PROBE_RC=%ERRORLEVEL%"
+
+:tryJavaProbeComplete
+if "%_PROBE_RC%"=="0" goto tryJavaParseProbe
+del /q "%_PROBE%" >NUL 2>&1
+set "_PROBE="
+exit /b 1
+
+:tryJavaParseProbe
+set "_RAW="
+for /f "tokens=3" %%v in ('findstr /b /l /i /c:"java version " /c:"openjdk version " "%_PROBE%"') do if not defined _RAW set "_RAW=%%v"
+del /q "%_PROBE%" >NUL 2>&1
+set "_PROBE="
+if not defined _RAW exit /b 1
+set "_RAW=%_RAW:"=%"
+set "_MAJOR="
+for /f "tokens=1,2 delims=." %%a in ("%_RAW%") do (
+  if "%%a"=="1" (set "_MAJOR=%%b") else (set "_MAJOR=%%a")
+)
+if not defined _MAJOR exit /b 1
+@REM Reject non-numeric majors (e.g. early-access "17-ea") so the numeric compare below is safe.
+for /f "delims=0123456789" %%z in ("%_MAJOR%") do exit /b 1
+if %_MAJOR% LSS %CAMEL_MIN_JAVA% exit /b 1
+set "CAMEL_JAVACMD=%_CAND%"
+exit /b 0

dsl/camel-jbang/camel-launcher/src/main/resources/bin/camel.sh

@@ -37,50 +37,61 @@ REPO=
 
 # OS specific support.  $var _must_ be set to either true or false.
 cygwin=false;
-darwin=false;
 case "`uname`" in
   CYGWIN*) cygwin=true ;;
-  Darwin*) darwin=true
-           if [ -z "$JAVA_VERSION" ] ; then
-             JAVA_VERSION="CurrentJDK"
-           else
-             echo "Using Java version: $JAVA_VERSION"
-           fi
-           if [ -z "$JAVA_HOME" ] ; then
-             JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/${JAVA_VERSION}/Home
-           fi
-           ;;
 esac
 
-if [ -z "$JAVA_HOME" ] ; then
-  if [ -r /etc/gentoo-release ] ; then
-    JAVA_HOME=`java-config --jre-home`
-  fi
-fi
-
-# For Cygwin, ensure paths are in UNIX format before anything is touched
+# For Cygwin, ensure JAVA_HOME is in UNIX format before it is probed.
 if $cygwin ; then
   [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
   [ -n "$CLASSPATH" ] && CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
 fi
 
-# If a specific java binary isn't specified search for the standard 'java' binary
-if [ -z "$JAVACMD" ] ; then
-  if [ -n "$JAVA_HOME"  ] ; then
-    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
-      # IBM's JDK on AIX uses strange locations for the executables
-      JAVACMD="$JAVA_HOME/jre/sh/java"
-    else
-      JAVACMD="$JAVA_HOME/bin/java"
-    fi
-  else
-    JAVACMD=`which java`
-  fi
-fi
+# --- Shared Java 17+ discovery contract ---
+# Candidates are tried in order: JAVACMD, $JAVA_HOME/bin/java, java on PATH, CAMEL_FALLBACK_JAVA.
+# ($JAVA_HOME is also how SDKMAN's java candidate exposes its runtime.)
+# Each must exist, be executable, and report a Java major version >= CAMEL_MIN_JAVA.
+# Probe output is captured and never printed during a normal invocation.
+CAMEL_MIN_JAVA=17
+
+# Echo the Java major version of the launcher in $1, or nothing if it cannot be determined.
+camel_java_major() {
+  _cjm_out=`"$1" -version </dev/null 2>&1` || return 1
+  _cjm_ver=`echo "$_cjm_out" | sed -n 's/.*version "\([0-9][0-9.]*\).*/\1/p' | head -n 1`
+  [ -n "$_cjm_ver" ] || return 1
+  case "$_cjm_ver" in
+    1.*) echo "$_cjm_ver" | cut -d. -f2 ;;
+    *)   echo "$_cjm_ver" | cut -d. -f1 ;;
+  esac
+}
+
+# Return 0 and set JAVACMD when $1 is an existing, executable, Java >= CAMEL_MIN_JAVA launcher.
+camel_try_java() {
+  [ -n "$1" ] || return 1
+  [ -x "$1" ] || return 1
+  _ctj_major=`camel_java_major "$1"` || return 1
+  [ -n "$_ctj_major" ] || return 1
+  { [ "$_ctj_major" -ge "$CAMEL_MIN_JAVA" ]; } 2>/dev/null || return 1
+  JAVACMD="$1"
+  return 0
+}
 
-if [ ! -x "$JAVACMD" ] ; then
-  echo "Error: JAVA_HOME is not defined correctly." 1>&2
-  echo "  We cannot execute $JAVACMD" 1>&2
+if camel_try_java "$JAVACMD"; then
+  :
+elif [ -n "$JAVA_HOME" ] && camel_try_java "$JAVA_HOME/bin/java"; then
+  :
+elif _camel_path_java=`command -v java 2>/dev/null` && camel_try_java "$_camel_path_java"; then
+  :
+elif camel_try_java "$CAMEL_FALLBACK_JAVA"; then
+  :
+else
+  echo "Error: no suitable Java runtime found. Camel CLI requires Java $CAMEL_MIN_JAVA or newer." 1>&2
+  echo "Checked the following sources (in order):" 1>&2
+  echo "  1. JAVACMD             = ${JAVACMD:-<unset>}" 1>&2
+  echo "  2. JAVA_HOME/bin/java  = ${JAVA_HOME:+$JAVA_HOME/bin/java}" 1>&2
+  echo "  3. java on PATH        = ${_camel_path_java:-<not found>}" 1>&2
+  echo "  4. CAMEL_FALLBACK_JAVA = ${CAMEL_FALLBACK_JAVA:-<unset>}" 1>&2
+  echo "Install a Java $CAMEL_MIN_JAVA+ runtime and either add it to PATH, set JAVA_HOME, or set JAVACMD." 1>&2
   exit 1
 fi