[MNG-6003] Drastically reduce JAVA_HOME discovery code

All special handling has been removed. JAVA_HOME must be set properly by
the user if necessary. Error messages have been graciously borrowed from
the Tomcat start scripts.

apache-maven/src/bin/mvn

@@ -41,52 +41,12 @@ fi
 
 # OS specific support. $var _must_ be set to either true or false.
 cygwin=false;
-darwin=false;
 mingw=false;
 case "`uname`" in
   CYGWIN*) cygwin=true;;
   MINGW*) mingw=true;;
-  Darwin*) darwin=true
-           #
-           # Look for the Apple JDKs first to preserve the existing behaviour, and then look
-           # for the new JDKs provided by Oracle.
-           #
-           if [ -z "$JAVA_HOME" ] && [ -L /System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK ] ; then
-             #
-             # Apple JDKs
-             #
-             export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home
-           fi
-
-           if [ -z "$JAVA_HOME" ] && [ -L /System/Library/Java/JavaVirtualMachines/CurrentJDK ] ; then
-             #
-             # Apple JDKs
-             #
-             export JAVA_HOME=/System/Library/Java/JavaVirtualMachines/CurrentJDK/Contents/Home
-           fi
-
-           if [ -z "$JAVA_HOME" ] && [ -L "/Library/Java/JavaVirtualMachines/CurrentJDK" ] ; then
-             #
-             # Oracle JDKs
-             #
-             export JAVA_HOME=/Library/Java/JavaVirtualMachines/CurrentJDK/Contents/Home
-           fi
-
-           if [ -z "$JAVA_HOME" ] && [ -x "/usr/libexec/java_home" ]; then
-             #
-             # Apple JDKs
-             #
-             export JAVA_HOME=`/usr/libexec/java_home`
-           fi
-           ;;
 esac
 
-if [ -z "$JAVA_HOME" ] ; then
-  if [ -r /etc/gentoo-release ] ; then
-    JAVA_HOME=`java-config --jre-home`
-  fi
-fi
-
 ## resolve links - $0 may be a link to Maven's home
 PRG="$0"
 
@@ -129,49 +89,19 @@ if $mingw ; then
   # TODO classpath?
 fi
 
-if [ -z "$JAVA_HOME" ]; then
-  javaExecutable="`which javac`"
-  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then
-    # readlink(1) is not available as standard on Solaris 10.
-    readLink=`which readlink`
-    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
-      if $darwin ; then
-        javaHome="`dirname \"$javaExecutable\"`"
-        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
-      else
-        javaExecutable="`readlink -f \"$javaExecutable\"`"
-      fi
-      javaHome="`dirname \"$javaExecutable\"`"
-      javaHome=`expr "$javaHome" : '\(.*\)/bin'`
-      JAVA_HOME="$javaHome"
-      export JAVA_HOME
-    fi
-  fi
-fi
-
-if [ -z "$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
+if [ -z "$JAVA_HOME" ] ; then
+  JAVACMD="`which java`"
+else
+  JAVACMD="$JAVA_HOME/bin/java"
 fi
 
 if [ ! -x "$JAVACMD" ] ; then
-  echo "Error: JAVA_HOME is not defined correctly." >&2
-  echo "  We cannot execute $JAVACMD" >&2
+  echo "The JAVA_HOME environment variable is not defined correctly" >&2
+  echo "This environment variable is needed to run this program" >&2
+  echo "NB: JAVA_HOME should point to a JDK not a JRE" >&2
   exit 1
 fi
 
-if [ -z "$JAVA_HOME" ] ; then
-  echo "Warning: JAVA_HOME environment variable is not set."
-fi
-
 CLASSWORLDS_JAR=`echo "${MAVEN_HOME}"/boot/plexus-classworlds-*.jar`
 CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
 

apache-maven/src/bin/mvn.cmd

@@ -30,10 +30,10 @@
 @REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
 @echo off
 @REM enable echoing my setting MAVEN_BATCH_ECHO to 'on'
-@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+@if "%MAVEN_BATCH_ECHO%"=="on" echo %MAVEN_BATCH_ECHO%
 
 @REM Execute a user defined script before this one
-if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+if not "%MAVEN_SKIP_RC%"=="" goto skipRcPre
 @REM check for pre script, once with legacy .bat ending and once with .cmd ending
 if exist "%USERPROFILE%\mavenrc_pre.bat" call "%USERPROFILE%\mavenrc_pre.bat"
 if exist "%USERPROFILE%\mavenrc_pre.cmd" call "%USERPROFILE%\mavenrc_pre.cmd"
@@ -44,24 +44,19 @@ if exist "%USERPROFILE%\mavenrc_pre.cmd" call "%USERPROFILE%\mavenrc_pre.cmd"
 set ERROR_CODE=0
 
 @REM ==== START VALIDATION ====
-if not "%JAVA_HOME%" == "" goto OkJHome
-
-echo.
-echo Error: JAVA_HOME not found in your environment. >&2
-echo Please set the JAVA_HOME variable in your environment to match the >&2
-echo location of your Java installation. >&2
-echo.
-goto error
+if not "%JAVA_HOME%"=="" goto OkJHome
+for %%i in (java.exe) do set "JAVACMD=%%~$PATH:i"
+goto checkJCmd
 
 :OkJHome
-if exist "%JAVA_HOME%\bin\java.exe" goto chkMHome
+set "JAVACMD=%JAVA_HOME%\bin\java.exe"
 
-echo.
-echo Error: JAVA_HOME is set to an invalid directory. >&2
-echo JAVA_HOME = "%JAVA_HOME%" >&2
-echo Please set the JAVA_HOME variable in your environment to match the >&2
-echo location of your Java installation. >&2
-echo.
+:checkJCmd
+if exist "%JAVACMD%" goto chkMHome
+
+echo The JAVA_HOME environment variable is not defined correctly >&2
+echo This environment variable is needed to run this program >&2
+echo NB: JAVA_HOME should point to a JDK not a JRE >&2
 goto error
 
 :chkMHome
@@ -114,7 +109,7 @@ cd "%EXEC_DIR%"
 :endDetectBaseDir
 
 set "jvmConfig=\.mvn\jvm.config"
-if not exist "%MAVEN_PROJECTBASEDIR%%jvmConfig%"  goto endReadAdditionalConfig
+if not exist "%MAVEN_PROJECTBASEDIR%%jvmConfig%" goto endReadAdditionalConfig
 
 @setlocal EnableExtensions EnableDelayedExpansion
 for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
@@ -122,13 +117,19 @@ for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do s
 
 :endReadAdditionalConfig
 
-set MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
-
 for %%i in ("%MAVEN_HOME%"\boot\plexus-classworlds-*) do set CLASSWORLDS_JAR="%%i"
-
 set CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
 
-%MAVEN_JAVA_EXE% %JVM_CONFIG_MAVEN_PROPS% %MAVEN_OPTS% %MAVEN_DEBUG_OPTS% -classpath %CLASSWORLDS_JAR% "-Dclassworlds.conf=%MAVEN_HOME%\bin\m2.conf" "-Dmaven.home=%MAVEN_HOME%" "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" "-Dlibrary.jansi.path=%MAVEN_HOME%\lib\ext" %CLASSWORLDS_LAUNCHER% %MAVEN_CMD_LINE_ARGS%
+"%JAVACMD%" ^
+  %JVM_CONFIG_MAVEN_PROPS% ^
+  %MAVEN_OPTS% ^
+  %MAVEN_DEBUG_OPTS% ^
+  -classpath %CLASSWORLDS_JAR% ^
+  "-Dclassworlds.conf=%MAVEN_HOME%\bin\m2.conf" ^
+  "-Dmaven.home=%MAVEN_HOME%" ^
+  "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" ^
+  "-Dlibrary.jansi.path=%MAVEN_HOME%\lib\ext" ^
+  %CLASSWORLDS_LAUNCHER% %MAVEN_CMD_LINE_ARGS%
 if ERRORLEVEL 1 goto error
 goto end
 
@@ -138,15 +139,15 @@ set ERROR_CODE=1
 :end
 @endlocal & set ERROR_CODE=%ERROR_CODE%
 
-if not "%MAVEN_SKIP_RC%" == "" goto skipRcPost
+if not "%MAVEN_SKIP_RC%"=="" goto skipRcPost
 @REM check for post script, once with legacy .bat ending and once with .cmd ending
 if exist "%USERPROFILE%\mavenrc_post.bat" call "%USERPROFILE%\mavenrc_post.bat"
 if exist "%USERPROFILE%\mavenrc_post.cmd" call "%USERPROFILE%\mavenrc_post.cmd"
 :skipRcPost
 
 @REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
-if "%MAVEN_BATCH_PAUSE%" == "on" pause
+if "%MAVEN_BATCH_PAUSE%"=="on" pause
 
-if "%MAVEN_TERMINATE_CMD%" == "on" exit %ERROR_CODE%
+if "%MAVEN_TERMINATE_CMD%"=="on" exit %ERROR_CODE%
 
 cmd /C exit /B %ERROR_CODE%