Get full Java version

Author: pyropunk (talk, contrib)

Description

This code will return the full java version of the installed JRE. If JRE is not installed it will try to read the version from the JDK and failing that will return "no java installed".

The Script

###############################################################################
; Find installed java version and return major, minor, micro and build/update version
; For some reason v1.2.1_004 did not give a build version, but it's the only one of its kind.
; There are 3 ways to get the build version:
;   1) from the UpdateVersion key
;   2) or from the MicroVersion key
;   3) or from the JavaHome key
;example
;  call GetJavaVersion
;  pop $0 ; major version
;  pop $1 ; minor version
;  pop $2 ; micro version
;  pop $3 ; build/update version
;  strcmp $0 "no" JavaNotInstalled
;  strcmp $3 "" nobuild
;  DetailPrint "$0.$1.$2_$3"
;  goto fin
;nobuild:
;  DetailPrint "$0.$1.$2"
;  goto fin
;JavaNotInstalled:
;  DetailPrint "Java Not Installed"
;fin:
Function GetJavaVersion
  push $R0
  push $R1
  push $2
  push $0
  push $3
  push $4
 
  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment" "CurrentVersion"
  StrCmp $2 "" DetectTry2
  ReadRegStr $3 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment\$2" "MicroVersion"
  StrCmp $3 "" DetectTry2
  ReadRegStr $4 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment\$2" "UpdateVersion"
  StrCmp $4 "" 0 GotFromUpdate
  ReadRegStr $4 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment\$2" "JavaHome"
  Goto GotJRE
DetectTry2:
  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Development Kit" "CurrentVersion"
  StrCmp $2 "" NoFound
  ReadRegStr $3 HKLM "SOFTWARE\JavaSoft\Java Development Kit\$2" "MicroVersion"
  StrCmp $3 "" NoFound
  ReadRegStr $4 HKLM "SOFTWARE\JavaSoft\Java Development Kit\$2" "UpdateVersion"
  StrCmp $4 "" 0 GotFromUpdate
  ReadRegStr $4 HKLM "SOFTWARE\JavaSoft\Java Development Kit\$2" "JavaHome"
GotJRE:
  ; calc build version
  strlen $0 $3
  intcmp $0 1 0 0 GetFromMicro
  ; get it from the path
GetFromPath:
  strlen $R0 $4
  intop $R0 $R0 - 1
  StrCpy $0 ""
loopP:
  StrCpy $R1 $4 1 $R0
  StrCmp $R1 "" DotFoundP
  StrCmp $R1 "_" UScoreFound
  StrCmp $R1 "." DotFoundP
  StrCpy $0 "$R1$0"
  Goto GoLoopingP
DotFoundP:
  push ""
  Exch 6
  goto CalcMicro
UScoreFound:
  push $0
  Exch 6
  goto CalcMicro
GoLoopingP:
  intcmp $R0 0 DotFoundP DotFoundP
  IntOp $R0 $R0 - 1
  Goto loopP
GetFromMicro:
  strcpy $4 $3
  goto GetFromPath
GotFromUpdate:
  push $4
  Exch 6
 
CalcMicro:
  Push $3 ; micro
  Exch 6
  ; break version into major and minor
  StrCpy $R0 0
  StrCpy $0 ""
loop:
  StrCpy $R1 $2 1 $R0
  StrCmp $R1 "" done
  StrCmp $R1 "." DotFound
  StrCpy $0 "$0$R1"
  Goto GoLooping
DotFound:
  Push $0 ; major
  Exch 5
  StrCpy $0 ""
GoLooping:
  IntOp $R0 $R0 + 1
  Goto loop
 
done:
  Push $0 ; minor
  Exch 7
  ; restore register values
  pop $0
  pop $2
  pop $R1
  pop $R0
  pop $3
  pop $4
  return
NoFound:
  pop $4
  pop $3
  pop $0
  pop $2
  pop $R1
  pop $R0
  push ""
  push "installed"
  push "java"
  push "no"
FunctionEnd

Comments welcome.