Develop Reference

Running java from VBA macro in Windows 7 bypassing System32 / SysWOW64 javaw.exe

Is there a way to bypass the 32-bit java version (maybe a different way to start a proccess in VBA to invoke the 64-bit version cmd, turn off the UAC or some other sort of tweek) that is being "forced" by the following VBA code (this is just an assumption, I am explaining the debugging process below):
handleDbl = Shell("javaw -cp theJar.jar com.java.SampleClass", vbNormalFocus)
The main point here is that I want to share my macro and avoid putting extra instructions on the recipient so I am trying to do everything on the code (I am using late binding on VBA code to avoid to setting References manually and that kind of stuff).
Debugging Process
An error was thrown so I used the following line instead:
handleDbl = Shell("cmd /k java -cp theJar.jar com.java.SampleClass", vbNormalFocus)
And got the error Exception in thread "main" java.lang.UnsupportedClassVersionError: Unsupported major.minor version so I checked the java -version and tried to find out which java was running with:
C:\>where java
C:\Windows\System32\java.exe
C:\Program Files\Java\_anyJava.x.x.x_\bin\java.exe
I went to System32 folder and there was no java there but I knew that redirection happens from there to C:\Windows\SysWOW64 so I compared the previously extracted java version against C:\Windows\SysWOW64\java.exe -version and they matched.
After that I checked my Outlook version and turned out to be a 32-bit installation. That was a hint but it was mostly that and that big *32 next to the cmd.exe in the Task Manager. I don't know if a 64-bit Outlook would make a difference or it would be the same because of the VBA implementation but that's how I concluded the Shell function from VBA is causing 32-bit java call.

Normally there is a JAVA_HOME environment variable set. If so, then you can do something like this:
Dim JavaExe As String
JavaExe = """" & Environ("JAVA_HOME") & "\bin\java.exe"""
handleDbl = Shell("cmd /k " & JavaExe & " -cp theJar.jar com.java.SampleClass", vbNormalFocus)
If it isn't set, you'll have to find it by some searching, before compiling the command.

Sam's answer is great but I just felt uneasy about user going through more settings so I wrote some functions to check java's versions and notify the user if it is not there (would have to install java in that case anyway) so here is my code. It might contain some helpful stuff.
Private Function IsJavaAvailable(ByVal displayMessage As Boolean, Optional ByVal isJavaMandatory As Boolean) As Boolean
Dim availability As Boolean
Dim minJavaVersion As Integer
minJavaVersion = 8
'isJavaSetup is a global variable
If (Not isJavaSetup) Then
javawPathQuoted = GetMinimumJavaVersion(minJavaVersion)
If StrComp(javawPathQuoted, "") <> 0 Then
isJavaSetup = True
End If
SetGlobalVars
End If
If javawPathQuoted = Empty Then
availability = False
Else
availability = True
End If
If (displayMessage) Then
If (isJavaMandatory) Then
If Not availability Then
MsgBox "This functionality is NOT available without Java " & minJavaVersion & "." & _
vbNewLine & vbNewLine & _
"Please install Java " & minJavaVersion & " or higher.", vbCritical, _
"Mimimum Version Required: Java " & minJavaVersion
End If
Else
If Not availability Then
MsgBox "Some features of this functionality were disabled." & _
vbNewLine & vbNewLine & _
"Please install Java " & minJavaVersion & " or higher.", vbExclamation, _
"Mimimum Version Required: Java " & minJavaVersion
End If
End If
End If
IsJavaAvailable = availability
End Function
Private Function GetMinimumJavaVersion(ByVal javaMinimumMajorVersionInt As Integer) As String
'Run a shell command, returning the output as a string
Dim commandStr As String
Dim javawPathVar As Variant
Dim javaPathStr As Variant
Dim javaVersionStr As String
Dim javaMajorVersionInt As Integer
Dim detectedJavaPaths As Collection
Dim javaVersionElements As Collection
Dim javaVersionOutput As Collection
Dim detectedJavaVersions As Collection
Dim suitableJavawPath As String
'Check available javaw executables in the SO
commandStr = "where javaw"
Set detectedJavaPaths = GetCommandOutput(commandStr)
Set detectedJavaVersions = New Collection
For Each javawPathVar In detectedJavaPaths
'Look for java.exe instead of javaw.exe by substituting it in path
' javaw.exe does NOT return version output like java.exe
javaPathStr = StrReverse(Replace(StrReverse(javawPathVar), StrReverse("javaw.exe"), StrReverse("java.exe"), , 1))
commandStr = """" & javaPathStr & """" & " -version"
Set javaVersionOutput = GetCommandOutput(commandStr)
javaVersionStr = javaVersionOutput.item(1)
Debug.Print "Getting java version: ", commandStr
Debug.Print "Version detected: "; javaVersionStr
Set javaVersionElements = SplitOnDelimiter(javaVersionStr, " ")
'Check that output is not an error or something else
'java version "1.8.0_75"
If javaVersionElements.Count > 2 Then
If StrComp(javaVersionElements.item(1), "java", vbTextCompare) = 0 Then
If StrComp(javaVersionElements.item(2), "version", vbTextCompare) = 0 Then
detectedJavaVersions.Add javaVersionStr
'Remove quotes from "1.8.0_75", split on '.', get 2nd item (java major version) and cast it to Integer
javaMajorVersionInt = CInt(SplitOnDelimiter(SplitOnDelimiter(javaVersionElements.item(3), """").item(1), ".").item(2))
'JAR will only run in Java 8 or later
If (javaMajorVersionInt >= javaMinimumMajorVersionInt) Then
'Validate that "javaw.exe" exists since the validation was made with "java.exe"
Debug.Print "Verifying if javaw.exe exists: ", javawPathVar
If Len(Dir(javawPathVar)) > 0 Then
suitableJavawPath = javawPathVar
Debug.Print "A suitable javaw.exe version found: ", suitableJavawPath
Exit For
End If
End If
End If
End If
End If
Next javawPathVar
GetMinimumJavaVersion = suitableJavawPath
End Function
Private Function GetCommandOutput(ByRef commandStr As String) As Collection
'Run a shell command, returning the output as a string
Dim shellObj As Object
Set shellObj = CreateObject("WScript.Shell")
'run command
Dim wshScriptExecObj As Object
Dim stdOutObj As Object
Dim stdErrObj As Object
Set wshScriptExecObj = shellObj.Exec(commandStr)
Set stdOutObj = wshScriptExecObj.StdOut
Set stdErrObj = wshScriptExecObj.StdErr
'handle the results as they are written to and read from the StdOut object
Dim fullOutputCollection As Collection
Set fullOutputCollection = New Collection
Dim lineStr As String
While Not stdOutObj.AtEndOfStream
lineStr = stdOutObj.ReadLine
If lineStr <> "" Then
fullOutputCollection.Add lineStr
End If
Wend
If fullOutputCollection.Count = 0 Then
While Not stdErrObj.AtEndOfStream
lineStr = stdErrObj.ReadLine
If lineStr <> "" Then
fullOutputCollection.Add lineStr
End If
Wend
End If
Set GetCommandOutput = fullOutputCollection
End Function

Exe - Embed JRE to a Standalone EXE? [duplicate]

I'm trying to install the most current platform (x64 or x86) appropriate Java Runtime Environment via Inno Setup (along with another application). I've found some script examples for how to detect the version and install if correct and adapted them to my needs but I keep running into this:
Unable to open file "path\to\JREInstall.exe":
CreateProcess failed: Code 5:
Access Is Denied
This is the code strictly responsible for installing the JRE:
[Setup]
AppName="JRE Setup"
AppVersion=0.1
DefaultDirName="JRE Setup"
[Languages]
Name: "english"; MessagesFile: "compiler:Default.isl"
[Files]
Source: "jre-8u11-windows-x64.exe"; DestDir: "{tmp}\JREInstall.exe"; \
Check: IsWin64 AND InstallJava();
Source: "jre-8u11-windows-i586.exe"; DestDir: "{tmp}\JREInstall.exe"; \
Check: (NOT IsWin64) AND InstallJava();
[Run]
Filename: "{tmp}\JREInstall.exe"; Parameters: "/s"; \
Flags: nowait postinstall runhidden runascurrentuser; Check: InstallJava()
[Code]
procedure DecodeVersion(verstr: String; var verint: array of Integer);
var
i,p: Integer; s: string;
begin
{ initialize array }
verint := [0,0,0,0];
i := 0;
while ((Length(verstr) > 0) and (i < 4)) do
begin
p := pos ('.', verstr);
if p > 0 then
begin
if p = 1 then s:= '0' else s:= Copy (verstr, 1, p - 1);
verint[i] := StrToInt(s);
i := i + 1;
verstr := Copy (verstr, p+1, Length(verstr));
end
else
begin
verint[i] := StrToInt (verstr);
verstr := '';
end;
end;
end;
function CompareVersion (ver1, ver2: String) : Integer;
var
verint1, verint2: array of Integer;
i: integer;
begin
SetArrayLength (verint1, 4);
DecodeVersion (ver1, verint1);
SetArrayLength (verint2, 4);
DecodeVersion (ver2, verint2);
Result := 0; i := 0;
while ((Result = 0) and ( i < 4 )) do
begin
if verint1[i] > verint2[i] then
Result := 1
else
if verint1[i] < verint2[i] then
Result := -1
else
Result := 0;
i := i + 1;
end;
end;
function InstallJava() : Boolean;
var
ErrCode: Integer;
JVer: String;
InstallJ: Boolean;
begin
RegQueryStringValue(
HKLM, 'SOFTWARE\JavaSoft\Java Runtime Environment', 'CurrentVersion', JVer);
InstallJ := true;
if Length( JVer ) > 0 then
begin
if CompareVersion(JVer, '1.8') >= 0 then
begin
InstallJ := false;
end;
end;
Result := InstallJ;
end;
In the full setup script the same message continues to come up.
How can I get the JRE Setup to run from this scripted setup file?

I was able to figure out the issue:
Evidently I was mistaken in my use of these lines:
Source: "jre-8u11-windows-x64.exe"; DestDir: "{tmp}\JREInstall.exe"; Check: IsWin64 AND InstallJava();
Source: "jre-8u11-windows-i586.exe"; DestDir: "{tmp}\JREInstall.exe"; Check: (NOT IsWin64) AND InstallJava();
and they should have been in place like so:
Source: "jre-8u11-windows-x64.exe"; DestDir: "{tmp}"; DestName: "JREInstall.exe"; Check: IsWin64 AND InstallJava();
Source: "jre-8u11-windows-i586.exe"; DestDir: "{tmp}"; DestName: "JREInstall.exe"; Check: (NOT IsWin64) AND InstallJava();
That seems to have solved the problem.
Also this line I was mistaken in:
Filename: "{tmp}\JREInstall.exe"; Parameters: "/s"; Flags: nowait postinstall runhidden runascurrentuser; Check: InstallJava()
It should have been:
Filename: "{tmp}\JREInstall.exe"; Parameters: "/s"; Flags: nowait runhidden runascurrentuser; Check: InstallJava()
This is the best solution my limited experience with this particular tool is able to come up with. I will look into the PrepareToInstall option when I have a chance but this works for now.

According to the initial question, "How do I install a JRE from an Inno script?", and taking as a starting solution the best proposed one, I propose a solution that I think works more coherently.
I understand that the user wants to install a JRE for their application if the target computer does not have installed a Java runtime environment or its version is lower than the required one. Ok, what I propose is to use the AfterInstall parameter and reorder a bit the distribution files in a different way.
We will first sort the files in the [Files] section in another way, putting first the redist install files.
Source: "redist\jre-8u121-windows-i586.exe"; DestDir: "{tmp}"; DestName: "JREInstaller.exe";\
Flags: deleteafterinstall; AfterInstall: RunJavaInstaller(); \
Check: (NOT IsWin64) AND InstallJava();
Source: "redist\jre-8u121-windows-x64.exe"; DestDir: "{tmp}"; DestName: "JREInstaller.exe"; \
Flags: deleteafterinstall; AfterInstall: RunJavaInstaller(); \
Check: IsWin64 AND InstallJava();
Source: "Myprog.exe"; DestDir: "{app}"; Flags: ignoreversion
The next step we must do is to modify the section [Run] as follows.
[Run]
Filename: "{app}\{#MyAppExeName}"; \
Description: "{cm:LaunchProgram,{#StringChange(MyAppName, '&', '&&')}}"; \
Flags: nowait postinstall skipifsilent
And last but not least, we implemented in the [Code] section the RunJavaInstaller() procedure as follows:
[Code]
procedure RunJavaInstaller();
var
StatusText: string;
ResultCode: Integer;
Path, Parameters: string;
begin
Path := '{tmp}\JREInstaller.exe';
{ http://docs.oracle.com/javase/8/docs/technotes/guides/install/config.html#table_config_file_options }
Parameters := '/s INSTALL_SILENT=Enable REBOOT=Disable SPONSORS=Disable REMOVEOUTOFDATEJRES=1';
StatusText:= WizardForm.StatusLabel.Caption;
WizardForm.StatusLabel.Caption:='Installing the java runtime environment. Wait a moment ...';
WizardForm.ProgressGauge.Style := npbstMarquee;
try
if not Exec(ExpandConstant(Path), Parameters, '', SW_SHOW, ewWaitUntilTerminated, ResultCode) then
begin
{ we inform the user we couldn't install the JRE }
MsgBox('Java runtime environment install failed with error ' + IntToStr(ResultCode) +
'. Try installing it manually and try again to install MyProg.', mbError, MB_OK);
end;
finally
WizardForm.StatusLabel.Caption := StatusText;
WizardForm.ProgressGauge.Style := npbstNormal;
end;
end;
You may need to replace the Enabled value with 1 and the Disabled value with 0 if the Java runtime installer is not working properly. I have not experienced any problem doing it this way. Anyways, in the code you have a comment with the Oracle link if you want to take a look.
Finally, since unfortunately we can not receive the installation progress status of the JRE in any way, we show a message and a progress bar so that the user does not have the feeling that the installer has hung.
To do this, we save the state before, execute Exec with the flag ewWaitUntilTerminated, to wait for that installation to finish before continuing with ours, and we restore the previous state once the function execution has finished.

Using JNI to call functions defined within a given DLL file

My objective was to use JNI to access functions from kernel32.dll. As you can see below, I was doing pretty bad. I wrote down the whole procedure in the answer.
Kernel32.java :
package tn.kernel;
public final class Kernel32 {
public static boolean loadKernel32(){
System.loadLibrary("kernel32");
return true;
}
public static native boolean K32EnumProcesses(int[] pProcessIds, int cb, int[] pBytesReturned);
}
MainClass.java :
package tn.kernel;
public class MainClass {
public static void main(String[] args) {
System.out.println("Program started.");
if(Kernel32.loadKernel32())
System.out.println("Kernel32.dll loaded.");
int n = 2000;
int[] procs = new int[n];
int ls = Integer.SIZE;
int[] rs = new int[1];
if(Kernel32.K32EnumProcesses(procs, ls * n, rs)){
System.out.println("Success");
}
System.out.println("Done.");
}
}
OUTPUT :
Program started.
Kernel32.dll loaded.
Exception in thread "main" java.lang.UnsatisfiedLinkError: tn.kernel.Kernel32.K32EnumProcesses([II[I)Z
at tn.kernel.Kernel32.K32EnumProcesses(Native Method)
at tn.kernel.MainClass.main(MainClass.java:15)
This the syntax for EnumProcesses :
BOOL WINAPI EnumProcesses(
_Out_ DWORD *pProcessIds,
_In_ DWORD cb,
_Out_ DWORD *pBytesReturned
);
If PSAPI_VERSION is 2 or greater, this function is defined as K32EnumProcesses in Psapi.h and exported in Kernel32.lib and Kernel32.dll. If PSAPI_VERSION is 1, this function is defined as EnumProcesses in Psapi.h and exported in Psapi.lib and Psapi.dll as a wrapper that calls K32EnumProcesses. Source : msnd.microsoft.com
I tried with both K32EnumProcesses and EnumProcesses. Same results.

Creating a 64 bits Dynamic-Link Library for Windows
Prerequisites: Visual Studio
1/ Create a Visual Studio C++ project (ex: dllexample)
• Select “Win32 Consol Application”
Select “DLL”
Select “Empty project”
2/ In “Solution explorer” right-click on “Header Files” > “Add” > “New Item…” > choose a name (ex: dllexample.h) > “Add”
• Define the headers of your functions in “dllexample.h” this way:
__declspec(dllexport) <type> funcName(parameters…);
…
3/ In “Solution explorer” right-click on “Source Files” > “Add” > “New Item…” > choose a name (ex: dllexample.cpp) > “Add”
• Use:
#include “dllexample.h”
• Define the body of your functions (from the “dllexample.h” header file) in the “dllexample.cpp” source file:
<type> funcName(parameters…){
//body instructions
}
• In the upper toolbar select “x64”
• Select “Build” > “Build Solution”
4/ Done
• You can find “dllexample.dll” and “dllexample.lib” in “projects/dllexample/x64/Debug”
• You can find “dllexample.h” in “projects/dllexample/dllexample”
 
Calling a 64 bits DLL file (ex: dllexample.dll) from another 64 bits DLL or executable file on Windows
Prerequisites: “dllexample.dll”, “dllexample.lib” and “dllexample.h” or a precise functions description or guide and Visual Studio
1/ Create a Visual Studio C++ project (ex: dllcall)
• Select “Win32 Consol Application”
Select “DLL” to create a DLL file, “Consol Application” to create an executable file
Select “Empty project”
2/ Copy “dllexample.dll”, “dllexample.lib” and “dllexample.h” to “projects/dllcall/dllcall”
3/ In “Solution explorer” right-click on “Header Files” > “Add” > “Existing Item…” > select ”dllexample.h” > “Add”
• If you’re making a DLL file, create a new header file (ex: dllcall.h) in which you define the headers of your functions this way:
__declspec(dllexport) <type> funcName(parameters…);
…
4/ In “Solution explorer” right-click on “Source Files” > “Add” > “New Item…” > choose a name (ex: dllcall.cpp) > “Add”
• Use:
#include “dllexample.h”
• If you’re creating a DLL file, use:
#include “dllcall.h”
And then define the body of the functions (from the “dllcall.h” header file) in the “dllcall.cpp” source file. At the same time you can call functions from “dllexample.h”:
<type> funcName(parameters…){
//body instructions
}
• In the upper toolbar select “x64”
• In “Solution explorer”, right-click on “dllcall” > “Properties” > “Linker” > “Input” > “Additional Dependencies” > “Edit” > add “dllexample.lib” (this option will be set only for the x64 debugger of the current Visual Studio project)
• Select “Build” > “Build Solution” to generate the DLL and the Import Library (.lib) files, “Run” to generate the executable file and test it
5/ Done
• You can find “dllcall.dll” and “dllcall.lib” or “dllcall.exe” in “projects/dllcall/x64/Debug”
• You can find “dllcall.h” in “projects/dllcall/dllcall”
Calling a 64 bits DLL file (ex: dllexample.dll) from a 64 bits Java program through JNI
Prerequisites: “dllexample.dll”, “dllexample.lib” and “dllexample.h” or a precise functions description or guide. Visual Studio, Eclipse with JNI plugin
1/ Create an Eclipse Java project (ex: dlltest)
2/ Create a class (ex: my.package.JNIClass)
• Define methods headers as close as the functions definitions in “dllexample.h” using keywords:
public static final native <type> funcName(parameters..);
…
• Run the project to generate “JNIClass.class”
3/ Open Command Line in folder “workspace/dllcall/src”
• Generate “my_package_JNIClass.h” header file by running command:
javah my.package.JNIClass
4/ Create a 64 bits DLL file (ex: dllcall.dll) that calls “dllexample.dll” and includes “my_package_JNIClass.h”
• In the “dllcall.cpp” source file, define the bodies of functions that are defined in the “my_package_JNIClass.h” header file
• “my_package_JNIClass.h” includes “jni.h”, to make it work, you must go to “Solution explorer” in Visual Studio and right-click on “Properties” > “Configuration Properties” > “C/C++” > “General” > “Additional Include Directories” > add the 64 bits “java/include” and “java/include/win32” paths (this option will be set only for the x64 debugger of the current Visual Studio project)
5/ Copy “dllcall.dll” and “dllexample.dll” to “workspace/dllcall/src”
• In “Package explorer”, right-click on “dlltest” > “Properties” > “Java Build Path” > “Source” > expand “my/package/src” > select “Native Library Location” > “Edit” > add “my/package/src” as location path
• Import the DLL files in “JNIClass.java” using:
static {
System.loadLibrary(“dllexample”);
System.loadLibrary(“dllcall”);
}
6/ If the 64 bits JRE is not selected, then go to “Run” > “Run Configurations” > “JRE” > “Alternate JREs” > “Installed JREs” > put the 64 bits Java JDK directory (Should be something like: “C:\Program Files\Java \jdk”, while 32 bits Java JDK can be found in the “Program Files (x86)” folder
7/ Done
• Now you can use the methods you defined in step 2

Java check latest version programmatically

Goal: check java's version on a machine (I can get this from java -version). Compare it with latest available from java website
I would like to know if there is any way I can check for latest Java releases assuming that I have JRE/JDK installed on a machine.
If I can do this through Java itself, my solution would become platform independent. I could use java.net.URL class to send a request to Java website and get the HTML, however the response would be dynamic as Oracle can change their website and styles and possibly will have maintenance issues in long run.
I have looked at javatester.org, but I would not want it through an applet but through command line (which I can add to a script).
Through javacpl.exe, I can schedule periodic checks, but I would like to do it on demand.

The answer is actually quite simple. http://java.com/en/download/testjava.jsp issues a request to http://java.com/applet/JreCurrentVersion2.txt. That file currently contains a single version number: '1.7.0_11'...which is the latest and greatest, indeed.
Java code example
try (BufferedReader br = new BufferedReader(new InputStreamReader(new URL(
"http://java.com/applet/JreCurrentVersion2.txt").openStream()))) {
String fullVersion = br.readLine();
String version = fullVersion.split("_")[0];
String revision = fullVersion.split("_")[1];
System.out.println("Version " + version + " revision " + revision);
} catch (IOException e) {
// handle properly
}
Update 2014-03-20
Eventhough Java 8 was recently released http://java.com/applet/JreCurrentVersion2.txt currently still returns 1.7.0_51.
Update 2016-07-13
Looks like we need to come back to this every few months... Currently you need to scan http://java.com/en/download/installed8.jsp for a JavaScript variable latest8Version. So, you could run curl -s https://java.com/en/download/installed8.jsp | grep latest8Version.
Update 2018-08-19
http://javadl-esd-secure.oracle.com/update/baseline.version is another hot spot as mentioned in some other answer.

An URL very similar to the now defunct "JreCurrentVersion2.txt":
http://javadl-esd-secure.oracle.com/update/baseline.version
The contents of the link look like this:
1.8.0_111
1.7.0_121
1.6.0_131
1.5.0_99
1.4.2_43
You can easily parse the contents to find the latest JRE versions.

UPDATE: I don't recommend this method because this JRE is the one that has the Ask.com toolbar. You're better off downloading it yourself and distributing it yourself.
The jusched.exe program accesses the following URL to find out what versions are available. I think it's less likely to change because jusched is installed on millions of computers.
https://javadl-esd-secure.oracle.com/update/1.7.0/map-m-1.7.0.xml
Here is a snippet of what it returns for me:
<?xml version="1.0" encoding="ISO-8859-1" standalone="yes" ?>
<java-update-map version="1.0">
<mapping>
<version>1.7.0_17</version>
<url>https://javadl-esd-secure.oracle.com/update/1.7.0/au-descriptor-1.7.0_25-b17.xml</url>
</mapping>
<mapping>
<version>1.7.0_21</version>
<url>https://javadl-esd-secure.oracle.com/update/1.7.0/au-descriptor-1.7.0_25-b17.xml</url>
</mapping>
</java-update-map>
To get the actual version that it is pointing to you have to fetch the above URL. Here is another snippet of what this XML looks like:
xml version="1.0" encoding="UTF-8" standalone="yes"?>
<!-- XML file to be staged anywhere, and pointed to by map.xml file -->
<java-update>
<information version="1.0" xml:lang="en">
<caption>Java Update - Update Available</caption>
<title>Java Update Available</title>
<description>Java 7 Update 25 is ready to install. Installing Java 7 Update 25 might uninstall the latest Java 6 from your system. Click the Install button to update Java now. If you wish to update Java later, click the Later button.</description>
<moreinfo>http://java.com/moreinfolink</moreinfo>
<AlertTitle>Java Update Available</AlertTitle>
<AlertText>A new version of Java is ready to be installed.</AlertText>
<moreinfotxt>More information...</moreinfotxt>
<url>http://javadl.sun.com/webapps/download/GetFile/1.7.0_25-b17/windows-i586/jre-7u25-windows-i586-iftw.exe</url>
<version>1.7.0_25-b17</version>
<post-status>https://nometrics.java.com</post-status>
<cntry-lookup>http://rps-svcs.sun.com/services/countrylookup</cntry-lookup>
<predownload></predownload>
<options>/installmethod=jau FAMILYUPGRADE=1 SPWEB=http://javadl-esd.sun.com/update/1.7.0/sp-1.7.0_25-b17</options>
<urlinfo>24595ec7f861bc67e572f1e4ad3992441335e1a7</urlinfo>
</information>
</java-update>
The version tag contains the full version number.

You could parse the Java SE Downloads page to extract the Java versions.
That way, you get the version of both JDK6 and JDK7, which allows you to test your particular JDK (6 or 7) against the latest Oracle one.
(As opposed to the Free Java Download page, which only lists the JDK7)
Her is a crude script in Go, which you can compile on Windows, Unix, MacOs into a single independent executable, and use within a command line or a script:
package main
import (
"bytes"
"encoding/xml"
"fmt"
"io/ioutil"
"net/http"
"os/exec"
"regexp"
)
type Jdk struct {
Url string
Ver string
update string
}
func main() {
resp, err := http.Get("http://www.oracle.com/technetwork/java/javase/downloads/index.html")
if err != nil {
fmt.Printf("Error on http Get: %v\n", err)
return
}
bodyb, err := ioutil.ReadAll(resp.Body)
if err != nil {
fmt.Printf("QueriesForOwner: error in ReadAll: %v\n", err)
return
}
br := bytes.NewBuffer(bodyb)
jdkre, err := regexp.Compile(`h3[^\r\n]+(/technetwork/java/javase/downloads/(jdk(?:6|7)(?:u(\d+))?)-downloads-\d+\.html)`)
if err != nil {
fmt.Printf("extract: error in regexp compilation: %v\n", err)
return
}
jdks := jdkre.FindAllSubmatch(br.Bytes(), -1)
jdk7 := Jdk{string(jdks[0][4]), string(jdks[0][5]), string(jdks[0][6])}
jdk6 := Jdk{string(jdks[1][7]), string(jdks[1][8]), string(jdks[1][9])}
fmt.Printf("Jdk7: %v\nJdk6: %v\n", jdk7, jdk6)
jver, err := exec.Command("java", "-version").CombinedOutput()
if err != nil {
fmt.Printf("*ExitError from java -version:", err)
return
}
fmt.Println("JVer: '", string(jver), "'")
jverre, err := regexp.Compile(`1.(\d).\d(?:_(\d+))"`)
jvers := jverre.FindSubmatch(jver)
jj := string(jvers[0])
jv := string(jvers[1])
ju := string(jvers[2])
jdk := jdk6
if jv == "7" {
jdk = jdk7
}
if jdk.update != ju {
fmt.Println("Local JDK *NOT* up-to-date: you have ", jj, ", Oracle has ", jdk.Ver)
} else {
fmt.Println("Local JDK *up-to-date*: you have ", jj, ", equals to Oracle, which has", jdk.Ver)
}
}
Again, this is a crude script, oriented toward JDK, and you would need to adapt it to your specific need, making its output and exit status match what you need for your script.
On my (PC) workstation, it returns:
Jdk7: {/technetwork/java/javase/downloads/jdk7u9-downloads-1859576.html jdk7u9 9}
Jdk6: {/technetwork/java/javase/downloads/jdk6u37-downloads-1859587.html jdk6u37 37}
JVer: ' java version "1.6.0_31"
Java(TM) SE Runtime Environment (build 1.6.0_31-b05)
Java HotSpot(TM) Client VM (build 20.6-b01, mixed mode, sharing)
'
Local JDK *NOT* up-to-date: you have 1.6.0_31" , Oracle has jdk6u37

I don't know what information you are exactly looking for, but you can get some version information using
System.getProperty("java.version");
If this is not what you're looking for, check the other available properties here:
http://docs.oracle.com/javase/6/docs/api/java/lang/System.html#getProperties()
As for the latest available version, I guess you'd have to parse this site manually:
http://java.com/en/download/index.jsp
The latest version is on there, currently it's
Version 7 Update 9
You write that this is not what you want because "Oracle can change their website and styles". However, you want to find out the latest version of Java by accessing their service (website in this case). As long as you're not paying for this, they have no obligation to you, and can change the service whenever they want without your consent. And even when you're a paying customer, the best you can hope for is that they will inform you of upcoming changes, and your maintenance issues will remain.
Remember, it's THEIR service you want to use.

I have solved a similar issue some time ago with this groovy script (disclaimer: is somehow a "toy" script):
#Grapes([
#Grab(group='org.ccil.cowan.tagsoup', module='tagsoup', version='1.2.1')
])
def slurper = new XmlSlurper(new org.ccil.cowan.tagsoup.Parser())
def url = new URL("http://www.java.com/download/manual.jsp")
def html
url.withReader { reader ->
html = slurper.parse(reader)
}
def lastJava = html.body.div.div.div.strong.text()
println "Last available java version: ${lastJava}"
println "Currently installed java version: ${System.properties["java.version"]}"
It yields something like:
Last available java version:
Version 7 Update 9
Currently installed java version: 1.7.0_07
If you want to avoid maintenance issues due to changes to the page structure, maybe a better option is to search for a line containing "Version x Update y".

To get all system variables
Properties properties = System.getProperties();
System.out.println(properties);
Sample output, this might be different in your system depending on your OS and Java JDK/JRE version.
{
java.runtime.name = Java(TM) SE Runtime Environment,
sun.boot.library.path = C:\Program Files\Java\jdk1.8.0_31\jre\bin,
java.vm.version = 25.31-b07,
java.vm.vendor = Oracle Corporation,
java.vendor.url = http://java.oracle.com/,
path.separator = ;,
idea.launcher.port = 7534,
java.vm.name = Java HotSpot(TM) 64-Bit Server VM,
file.encoding.pkg = sun.io,
user.country = NP,
user.script = ,
sun.java.launcher = SUN_STANDARD,
sun.os.patch.level = ,
java.vm.specification.name = Java Virtual Machine Specification,
user.dir = C:\Users\...\roid,
java.runtime.version = 1.8.0_31-b13,
java.awt.graphicsenv = sun.awt.Win32GraphicsEnvironment,
java.endorsed.dirs = C:\Program Files\Java\jdk1.8.0_31\jre\lib\endorsed,
os.arch = amd64,
java.io.tmpdir = C:\Windows\TEMP\,
line.separator = ,
java.vm.specification.vendor = Oracle Corporation,
user.variant = ,
os.name = Windows 8.1,
sun.jnu.encoding = Cp1252,
java.library.path = C:\Program...roid,
java.specification.name = Java Platform API Specification,
java.class.version = 52.0,
sun.management.compiler = HotSpot 64-Bit Tiered Compilers,
os.version = 6.3,
user.home = C:\Users\Xxx,
user.timezone = Asia/Kathmandu,
java.awt.printerjob = sun.awt.windows.WPrinterJob,
file.encoding = UTF-8,
idea.launcher.bin.path = C:\Program Files (x86)\xxx\bin,
java.specification.version = 1.8,
java.class.path = C:\Program Files\Java\jdk1.8.0_31\jre\lib\charsets.jar;...,
user.name = Xxx,
java.vm.specification.version = 1.8,
sun.java.command = com.xxxx.ameras,
java.home = C:\Program Files\Java\jdk1.8.0_31\jre,
sun.arch.data.model = 64,
user.language = en,
java.specification.vendor = Oracle Corporation,
awt.toolkit = sun.awt.windows.WToolkit,
java.vm.info = mixed mode,
java.version = 1.8.0_31,
java.ext.dirs = C:\Program Files\Java\jdk1.8.0_31\jre\lib\ext;...,
java.vendor = Oracle Corporation,
file.separator = \,
java.vendor.url.bug = http://bugreport.sun.com/bugreport/,
sun.io.unicode.encoding = UnicodeLittle,
sun.cpu.endian = little,
sun.desktop = windows,
sun.cpu.isalist = amd64
}
Retrive only specific variable
String javaVersion = System.getProperty("java.version");
System.out.println(javaVersion);
Output
1.8.0_31

#MarcelStör's solution no longer works - the version in the file is 1.8.0_51, while the actual latest version is 1.8.0_91/92. If you go to the Java test page in Firefox or Chrome and open the development console you can get the variable latest8Version which currently is 1.8.0_91. This could be wrapped in a Selenium/Firefox solution, but is an incredibly hacky way of getting this information.

System.getProperty("java.vm.specification.version");
System.getProperty("java.version");

How to update PATH variable permanently from Windows command line?

If I execute set PATH=%PATH%;C:\\Something\\bin from the command line (cmd.exe) and then execute echo %PATH% I see this string added to the PATH. If I close and open the command line, that new string is not in PATH.
How can I update PATH permanently from the command line for all processes in the future, not just for the current process?
I don't want to do this by going to System Properties → Advanced → Environment variables and update PATH there.
This command must be executed from a Java application (please see my other question).

You can use:
setx PATH "%PATH%;C:\\Something\\bin"
However, setx will truncate the stored string to 1024 bytes, potentially corrupting the PATH.
/M will change the PATH in HKEY_LOCAL_MACHINE instead of HKEY_CURRENT_USER. In other words, a system variable, instead of the user's. For example:
SETX /M PATH "%PATH%;C:\your path with spaces"
You have to keep in mind, the new PATH is not visible in your current cmd.exe.
But if you look in the registry or on a new cmd.exe with "set p" you can see the new value.

The documentation on how to do this can be found on MSDN. The key extract is this:
To programmatically add or modify system environment variables, add them to the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment registry key, then broadcast a WM_SETTINGCHANGE message with lParam set to the string "Environment". This allows applications, such as the shell, to pick up your updates.
Note that your application will need elevated admin rights in order to be able to modify this key.
You indicate in the comments that you would be happy to modify just the per-user environment. Do this by editing the values in HKEY_CURRENT_USER\Environment. As before, make sure that you broadcast a WM_SETTINGCHANGE message.
You should be able to do this from your Java application easily enough using the JNI registry classes.

I caution against using the command
setx PATH "%PATH%;C:\Something\bin"
to modify the PATH variable because of a "feature" of its implementation. On many (most?) installations these days the variable will be lengthy - setx will truncate the stored string to 1024 bytes, potentially corrupting the PATH (see the discussion here).
(I signed up specifically to flag this issue, and so lack the site reputation to directly comment on the answer posted on May 2 '12. My thanks to beresfordt for adding such a comment)

This Python-script[*] does exactly that:
"""
Show/Modify/Append registry env-vars (ie `PATH`) and notify Windows-applications to pickup changes.
First attempts to show/modify HKEY_LOCAL_MACHINE (all users), and
if not accessible due to admin-rights missing, fails-back
to HKEY_CURRENT_USER.
Write and Delete operations do not proceed to user-tree if all-users succeed.
Syntax:
{prog} : Print all env-vars.
{prog} VARNAME : Print value for VARNAME.
{prog} VARNAME VALUE : Set VALUE for VARNAME.
{prog} +VARNAME VALUE : Append VALUE in VARNAME delimeted with ';' (i.e. used for `PATH`).
{prog} -VARNAME : Delete env-var value.
Note that the current command-window will not be affected,
changes would apply only for new command-windows.
"""
import winreg
import os, sys, win32gui, win32con
def reg_key(tree, path, varname):
return '%s\%s:%s' % (tree, path, varname)
def reg_entry(tree, path, varname, value):
return '%s=%s' % (reg_key(tree, path, varname), value)
def query_value(key, varname):
value, type_id = winreg.QueryValueEx(key, varname)
return value
def yield_all_entries(tree, path, key):
i = 0
while True:
try:
n,v,t = winreg.EnumValue(key, i)
yield reg_entry(tree, path, n, v)
i += 1
except OSError:
break ## Expected, this is how iteration ends.
def notify_windows(action, tree, path, varname, value):
win32gui.SendMessage(win32con.HWND_BROADCAST, win32con.WM_SETTINGCHANGE, 0, 'Environment')
print("---%s %s" % (action, reg_entry(tree, path, varname, value)), file=sys.stderr)
def manage_registry_env_vars(varname=None, value=None):
reg_keys = [
('HKEY_LOCAL_MACHINE', r'SYSTEM\CurrentControlSet\Control\Session Manager\Environment'),
('HKEY_CURRENT_USER', r'Environment'),
]
for (tree_name, path) in reg_keys:
tree = eval('winreg.%s'%tree_name)
try:
with winreg.ConnectRegistry(None, tree) as reg:
with winreg.OpenKey(reg, path, 0, winreg.KEY_ALL_ACCESS) as key:
if not varname:
for regent in yield_all_entries(tree_name, path, key):
print(regent)
else:
if not value:
if varname.startswith('-'):
varname = varname[1:]
value = query_value(key, varname)
winreg.DeleteValue(key, varname)
notify_windows("Deleted", tree_name, path, varname, value)
break ## Don't propagate into user-tree.
else:
value = query_value(key, varname)
print(reg_entry(tree_name, path, varname, value))
else:
if varname.startswith('+'):
varname = varname[1:]
value = query_value(key, varname) + ';' + value
winreg.SetValueEx(key, varname, 0, winreg.REG_EXPAND_SZ, value)
notify_windows("Updated", tree_name, path, varname, value)
break ## Don't propagate into user-tree.
except PermissionError as ex:
print("!!!Cannot access %s due to: %s" %
(reg_key(tree_name, path, varname), ex), file=sys.stderr)
except FileNotFoundError as ex:
print("!!!Cannot find %s due to: %s" %
(reg_key(tree_name, path, varname), ex), file=sys.stderr)
if __name__=='__main__':
args = sys.argv
argc = len(args)
if argc > 3:
print(__doc__.format(prog=args[0]), file=sys.stderr)
sys.exit()
manage_registry_env_vars(*args[1:])
Below are some usage examples, assuming it has been saved in a file called setenv.py somewhere in your current path.
Note that in these examples i didn't have admin-rights, so the changes affected only my local user's registry tree:
> REM ## Print all env-vars
> setenv.py
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
HKEY_CURRENT_USER\Environment:PATH=...
...
> REM ## Query env-var:
> setenv.py PATH C:\foo
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
!!!Cannot find HKEY_CURRENT_USER\Environment:PATH due to: [WinError 2] The system cannot find the file specified
> REM ## Set env-var:
> setenv.py PATH C:\foo
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
---Set HKEY_CURRENT_USER\Environment:PATH=C:\foo
> REM ## Append env-var:
> setenv.py +PATH D:\Bar
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
---Set HKEY_CURRENT_USER\Environment:PATH=C:\foo;D:\Bar
> REM ## Delete env-var:
> setenv.py -PATH
!!!Cannot access HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment:PATH due to: [WinError 5] Access is denied
---Deleted HKEY_CURRENT_USER\Environment:PATH
[*] Adapted from: http://code.activestate.com/recipes/416087-persistent-environment-variables-on-windows/

For reference purpose, for anyone searching how to change the path via code, I am quoting a useful post by a Delphi programmer from this web page: http://www.tek-tips.com/viewthread.cfm?qid=686382
TonHu (Programmer) 22 Oct 03 17:57 I found where I read the original
posting, it's here:
http://news.jrsoftware.org/news/innosetup.isx/msg02129....
The excerpt of what you would need is this:
You must specify the string "Environment" in LParam. In Delphi you'd
do it this way:
SendMessage(HWND_BROADCAST, WM_SETTINGCHANGE, 0, Integer(PChar('Environment')));
It was suggested by Jordan Russell, http://www.jrsoftware.org, the
author of (a.o.) InnoSetup, ("Inno Setup is a free installer for
Windows programs. First introduced in 1997, Inno Setup today rivals
and even surpasses many commercial installers in feature set and
stability.") (I just would like more people to use InnoSetup )
HTH

In a corporate network, where the user has only limited access and uses portable apps, there are these command line tricks:
Query the user env variables: reg query "HKEY_CURRENT_USER\Environment". Use "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment" for LOCAL_MACHINE.
Add new user env variable: reg add "HKEY_CURRENT_USER\Environment" /v shared_dir /d "c:\shared" /t REG_SZ. Use REG_EXPAND_SZ for paths containing other %% variables.
Delete existing env variable: reg delete "HKEY_CURRENT_USER\Environment" /v shared_dir.

This script
http://www.autohotkey.com/board/topic/63210-modify-system-path-gui/
includes all the necessary Windows API calls which can be refactored for your needs. It is actually an AutoHotkey GUI to change the System PATH easily. Needs to be run as an Administrator.