[Windows] Search for Java installation in registry using BATCH script

Check for the Java installation scanning through registry. This batch file searches for Java 6 Update 16 (32 bit) or above. If any version of Java that is older than this is found, it will error out.

@ECHO OFF

setlocal ENABLEEXTENSIONS

IF %PROCESSOR_ARCHITECTURE%==AMD64 GOTO CHECK_JAVA_64
IF %PROCESSOR_ARCHITECTURE%==x86 GOTO CHECK_JAVA_32

@ECHO Detecting Java version installed.
:CHECK_JAVA_64
@ECHO Detecting if it is 64 bit machine
set KEY_NAME="HKEY_LOCAL_MACHINE\Software\Wow6432Node\JavaSoft\Java Runtime Environment"
set VALUE_NAME=CurrentVersion
set VALUE_FAMILYNAME=Java6FamilyVersion

FOR /F "usebackq skip=2 tokens=1-3" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_NAME% 2^>nul`) DO (
 set ValueName=%%A
 set ValueType=%%B
 set ValueValue=%%C
)
@ECHO CurrentVersion %ValueValue%

IF "%ValueValue%" == "1.6" (
 FOR /F "usebackq skip=2 tokens=1-3" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_FAMILYNAME% 2^>nul`) DO (
 set ValueFamilyName=%%A
 set ValueFamilyType=%%B
 set ValueFamilyValue=%%C
 )
)
IF "%ValueValue%" == "1.6" (
 IF "%ValueFamilyValue%" LSS "1.6.0_16" GOTO JAVA_NOT_INSTALLED
)

SET KEY_NAME="%KEY_NAME:~1,-1%\%ValueValue%"
SET VALUE_NAME=JavaHome

if defined ValueName (
 FOR /F "usebackq skip=2 tokens=1,2*" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_NAME% 2^>nul`) DO (
 set ValueName2=%%A
 set ValueType2=%%B
 set JRE_PATH2=%%C

 if defined ValueName2 (
 set ValueName = %ValueName2%
 set ValueType = %ValueType2%
 set ValueValue = %JRE_PATH2%
 )
 )
)

IF NOT "%JRE_PATH2%" == "" GOTO JAVA_INSTALLED
IF "%JRE_PATH2%" == "" GOTO JAVA_NOT_INSTALLED

:CHECK_JAVA_32
@ECHO Detecting if it is 32 bit machine
set KEY_NAME="HKEY_LOCAL_MACHINE\Software\JavaSoft\Java Runtime Environment"
set VALUE_NAME=CurrentVersion
set VALUE_FAMILYNAME=Java6FamilyVersion

FOR /F "usebackq skip=2 tokens=1-3" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_NAME% 2^>nul`) DO (
 set ValueName=%%A
 set ValueType=%%B
 set ValueValue=%%C
)
@ECHO CurrentVersion %ValueValue%
IF "%ValueValue%" == "" GOTO CHECK_JAVA_32

IF "%ValueValue%" == "1.6" (
 FOR /F "usebackq skip=2 tokens=1-3" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_FAMILYNAME% 2^>nul`) DO (
 set ValueFamilyName=%%A
 set ValueFamilyType=%%B
 set ValueFamilyValue=%%C
 )
)
IF "%ValueValue%" == "1.6" (
 IF "%ValueFamilyValue%" LSS "1.6.0_16" GOTO JAVA_NOT_INSTALLED
)

SET KEY_NAME="%KEY_NAME:~1,-1%\%ValueValue%"
SET VALUE_NAME=JavaHome

if defined ValueName (
 FOR /F "usebackq skip=2 tokens=1,2*" %%A IN (`REG QUERY %KEY_NAME% /v %VALUE_NAME% 2^>nul`) DO (
 set ValueName2=%%A
 set ValueType2=%%B
 set JRE_PATH2=%%C

 if defined ValueName2 (
 set ValueName = %ValueName2%
 set ValueType = %ValueType2%
 set ValueValue = %JRE_PATH2%
 )
 )
)

IF "%JRE_PATH2%" == "" GOTO JAVA_NOT_INSTALLED

:JAVA_INSTALLED
REM Do whatever you want to do when Java is installed
GOTO END

:JAVA_NOT_INSTALLED
REM Do whatever you want to do when Java is NOT installed
PAUSE
GOTO END

:END
REM End of Batch File