Runtime.exec with a third argument (current working directory argument) that
refers to a nonexistant directory can cause the child process to hang. This
is on Solaris 8 w/ 1.4.2-b18.

The following testcase will hang waiting for the hung child process:

import java.io.*;

public class FAEBug {
public static void main(String args[]) {
try {
Process p = Runtime.getRuntime().exec("/usr/bin/ls",
null,
new File("foo"));
p.waitFor();
} catch (Exception e) {
e.printStackTrace();
}
}
}

See also comments.