How do you determine 32 or 64 bit architecture of Windows using Java?

I don't exactly trust reading the os.arch system variable. While it works if a user is running a 64bit JVM on a 64bit system. It doesn't work if the user is running a 32bit JVM on a 64 bit system.

The following code works for properly detecting Windows 64-bit operating systems. On a Windows 64 bit system the environment variable"Programfiles(x86)" will be set. It will NOT be set on a 32-bit system and java will read it as null.

boolean is64bit = false;if (System.getProperty("os.name").contains("Windows")) {    is64bit = (System.getenv("ProgramFiles(x86)") != null);} else {    is64bit = (System.getProperty("os.arch").indexOf("64") != -1);}

For other operating systems like Linux or Solaris or Mac we may see this problem as well. So this isn't a complete solution. For mac you are probably safe because apple locks down the JVM to match the OS. But Linux and Solaris, etc.. they may still use a 32-bit JVM on their 64-bit system. So use this with caution.

Please note, the os.arch property will only give you the architecture of the JRE, not of the underlying os.

If you install a 32 bit jre on a 64 bit system, System.getProperty("os.arch") will return x86

In order to actually determine the underlying architecture, you will need to write some native code. See this post for more info (and a link to sample native code)

I used the command prompt (command --> wmic OS get OSArchitecture) to get the OS architecture. The following program helps get all the required parameters:

import java.io.*;public class User {    public static void main(String[] args) throws Exception {        System.out.println("OS --> "+System.getProperty("os.name"));   //OS Name such as Windows/Linux        System.out.println("JRE Architecture --> "+System.getProperty("sun.arch.data.model")+" bit.");       // JRE architecture i.e 64 bit or 32 bit JRE        ProcessBuilder builder = new ProcessBuilder(            "cmd.exe", "/c","wmic OS get OSArchitecture");        builder.redirectErrorStream(true);        Process p = builder.start();        String result = getStringFromInputStream(p.getInputStream());        if(result.contains("64"))            System.out.println("OS Architecture --> is 64 bit");  //The OS Architecture        else            System.out.println("OS Architecture --> is 32 bit");        }    private static String getStringFromInputStream(InputStream is) {        BufferedReader br = null;        StringBuilder sb = new StringBuilder();        String line;        try {            br = new BufferedReader(new InputStreamReader(is));            while ((line = br.readLine()) != null) {                sb.append(line);            }        } catch (IOException e) {            e.printStackTrace();        } finally {            if (br != null) {                try {                    br.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return sb.toString();    }}