It appears that the quoting requirements for backslash are inconsistent between
Windows95, Windows98, and WindowsNT.  In some cases, the backslash is
interpreted so we must add extra "\" for later processing and in other cases it
is not.  This causes difficulties in setting environment variables for calling
Runtime.exec() in code which must run on all three platforms.  

In the following example, java.net.InetAddress.getLocalHost() requires windir
(for 95 and 98) or SystemRoot (for NT) to be set.  If the environment variable
is not not defined properly then the DNS lookup will fail and an
UnknownHostException will be thrown.  Please refer to the comments within the
code for details on which backslash quoting convention is required for each
platform.

STEPS TO REPRODUCE:
1.  $ javac QuoteBackslash.java
2.  $ javac GetLocalHost.java
3.  $ java QuoteBackslash
    [ modify declaration of "env" for different platforms as necessary ]

FILE: QuoteBackslash.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class QuoteBackslash {
    public static void main(String [] args) {
 	String [] cmd = {"l:\\jdk1.3\\win32\\bin\\java",
			 "-classpath",
			 ".",
 			 "GetLocalHost"};

	// 95 - ok
	//String [] env = {"windir=c:\\windows"};
	// 95 - not ok
	String [] env = {"windir=c:\\\\windows"};

	// 98 - not ok???
	//String [] env = {"windir=c:\\windows"};
	// 98 - ok
	//String [] env = {"windir=c:\\\\windows"};

	// NT - ok
	//String [] env = {"SystemRoot=c:\\winnt"};
	// NT - ok
	//String [] env = {"SystemRoot=c:\\\\winnt"};

	Process p = null;
	try {
	    p = Runtime.getRuntime().exec(cmd, env);
	    //p = Runtime.getRuntime().exec(cmd);
	    int exitCode = p.waitFor();

	    String line;

	    BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
	    while ((line = in.readLine()) != null)
		System.out.println(line);
	    in.close();

	    BufferedReader err = new BufferedReader(new InputStreamReader(p.getErrorStream()));
	    while ((line = err.readLine()) != null)
		System.out.println(line);
	    err.close();

	    //System.out.println("*** exit code: " + exitCode);
	} catch (InterruptedException e) {
	    if (p != null)
		p.destroy();
	} catch (IOException e) {
	    e.printStackTrace();
	}
    }
}

FILE: GetLocalHost.java

import java.net.*;

public class GetLocalHost {
    static InetAddress addr;

    public static void main(String args[]) throws Exception {
        addr = InetAddress.getLocalHost();
        System.out.println("ADDR: " + addr);
    }
}

OUTPUT (win95):

// "windir=c:\\windows"
[I:/work/bug/runtime] l:/java/jdk1.3/win32/bin/java QuoteBackslash
ADDR: kaveri.eng.sun.com/129.144.125.120

// "windir=c:\\\\windows"
[I:/work/bug/runtime] l:/java/jdk1.3/win32/bin/java QuoteBackslash
java.net.UnknownHostException: kaveri.eng.sun.com
        at java.net.InetAddress.getAllByName0(InetAddress.java:579)
        at java.net.InetAddress.getAllByName0(InetAddress.java:548)
        at java.net.InetAddress.getAllByName(InetAddress.java:541)
        at java.net.InetAddress.getLocalHost(InetAddress.java:731)
        at GetLocalHost.main(GetLocalHost.java:10)
Exception in thread "main"


Earlier tests seem to indicate that this inconsistency exists at least as far
back as JDK1.1.6.  This behaviour is particularly problematic since it is
impossible to distinguish 95 from 98 in Cricket.

The behaviour in NT or 98 is preferable.

iris.garcia@eng 1999-07-19