Inno Setup - Setting Java Environment Variable

Question

I am using Inno Setup to make an installer for a project I am working on, and I need it to set the java environment variable, so that when they run cmd they don't get a java not found error, or something like that.

I have found a few other posts related to Inno Setup and the setting environment variables, but does anyone know something specific to this instance?

Answer 1

Assuming Java is installed in its default location program files/Java, something like this should work in your case:

[Registry]
; set PATH
Root: HKCU; Subkey: "Environment"; ValueType:string; ValueName:"PATH"; ValueData:"{olddata};{pf}\Java\bin"; Flags: preservestringtype
; set JAVA_HOME
Root: HKCU; Subkey: "Environment"; ValueType:string; ValueName:"JAVA_HOME"; ValueData:"{pf}\Java"; Flags: preservestringtype

[Setup]
; Tell Windows Explorer to reload the environment
ChangesEnvironment=yes

I'm not sure which environment variable you want to set -- PATH or JAVA_HOME -- so I've added them both.

Changing PATH shouldn't be necessary since the Java installer tends to add itself to the path; IIRC it copies java.exe and javaw.exe to one of the system directories.

Answer 2

Adding up to @Joni's answer, you can get the Java installation directory from the registry and use script constants to set your environment variable:

(EDIT: thanks to @TLama for code correction!)

[Registry]
Root: HKCU; Subkey: "Environment"; ValueType:string; ValueName:"JAVA_HOME"; ValueData:"{code:GetJava32Path|6}"; Flags: preservestringtype

[Code]
const
  RegKeyJRE = 'SOFTWARE\JavaSoft\Java Runtime Environment\';

function GetJava32Path(MinVersion: string): string;
var
  I: Integer;
  Path: string;
  Versions: TArrayOfString;
begin
  Result := '';
  if RegGetSubkeyNames(HKLM, RegKeyJRE, Versions) then
    for I := 0 to GetArrayLength(Versions)-1 do
      if (Versions[I][2] = '.') and (Versions[I][3] >= MinVersion) and
        RegQueryStringValue(HKLM32, RegKeyJRE + Versions[I], 'JavaHome', Path) then
      begin
        Result := Path;
        Exit;
      end;
end;

(NB I'm far from being a Pascal-script expert, the code could be a lot better, though now it was corrected by @TLama :))