Mac/Linux Users help

How can i get my client/server to support mac and Linux users!

[code]public static String findcachedir()
{
boolean exists = (new File(System.getProperty(“user.home”) + “/.OS-Legacy-V1.2/”)).exists();
if (exists) {
return System.getProperty(“user.home”) + “/.OS-Legacy-V1.2/”;
} else {
File f = new File(System.getProperty(“user.home”) + “/.OS-Legacy-V1.2/”);
f.mkdir();
return System.getProperty(“user.home”) + “/.OS-Legacy-V1.2/”;
}
}
public static String sencondDir() {
File file = new File(“c:/.OS-Legacy-V1.2/”);
if (!file.exists())
file.mkdir();
return file.toString();
}

public static String findcachedirORIG()
{
    String as[] = {
        "c:/windows/", "c:/winnt/", "d:/windows/", "d:/winnt/", "e:/windows/", "e:/winnt/", "f:/windows/", "f:/winnt/", "c:/", "~/",
        "/tmp/", "", "c:/rscache", "/rscache"
    };
    if(storeid < 32 || storeid > 34)
        storeid = 32;
    String s = ".file_store_" + storeid;
    for(int i = 0; i < as.length; i++)
        try
        {
            String s1 = as[i];
            if(s1.length() > 0)
            {
                File file = new File(s1);
                if(!file.exists())
                    continue;
            }
            File file1 = new File(s1 + s);
            if(file1.exists() || file1.mkdir())
                return s1 + s + "/";
        }
        catch(Exception _ex) { }
 
    return null;

}

public static int getuid(String s)
{
    try
    {
        File file = new File(s + "uid.dat");
        if(!file.exists() || file.length() < 4L)
        {
            DataOutputStream dataoutputstream = new DataOutputStream(new FileOutputStream(s + "uid.dat"));
            dataoutputstream.writeInt((int)(Math.random() * 99999999D));
            dataoutputstream.close();
        }
    }
    catch(Exception _ex) { }
    try
    {
        DataInputStream datainputstream = new DataInputStream(new FileInputStream(s + "uid.dat"));
        int i = datainputstream.readInt();
        datainputstream.close();
        return i + 1;
    }
    catch(Exception _ex)
    {
        return 0;
    }
}[/code]