Update web URLs (#117)

* Update all occurrences of URLs for UNIX and Java

* Point to Internet Archive for [8lgm]

Author: lechten

distmid.tex

@@ -832,7 +832,7 @@ \section*{Exploration Projects}
 \section*{Notes}
 The topics in this chapter are subject to particularly rapid technical
 developments.  As such, your best source of information is likely to
-be websites.  The Java website, \textit{\url{http://java.sun.com}}, has
+be websites.  The Java website, \textit{\url{http://www.oracle.com/technetwork/java/index.html}}, has
 information both on RMI and on Java EE, which includes JMS.
 The information on this site---and in many
 published books for that matter---tends to emphasize the technical

persistence.tex

@@ -2948,7 +2948,7 @@ \section*{Notes}
 in an appropriate order.
 
 For more information on the POSIX API, see
-\textit{\url{http://www.unix.org/}}.  For the original UNIX API from which POSIX
+\textit{\url{http://opengroup.org/unix}}.  For the original UNIX API from which POSIX
 evolved (as did later UNIX versions, for that matter), see the 1974
 article by \index{Ritchie, Dennis M.}Ritchie and \index{Thompson, Ken}Thompson~\cite{jhs2.3}.  That paper also
 sketches the internal structure of the initial UNIX file system.

processes.tex

@@ -2557,7 +2557,7 @@ \section*{Notes}
 
 You can supplement my brief introduction to the POSIX API for process
 management in two ways.  One is by reading the official documentation;
-the POSIX standard is on the web at \textit{\url{http://www.unix.org}}, and the
+the POSIX standard is on the web at \textit{\url{http://opengroup.org/unix}}, and the
 documentation for specific implementations (such as Linux) is also
 easily available.  The other approach, which is likely to be more
 useful at first, would be to read a book on the topic.  Two good choices

synchronization.tex

@@ -2804,7 +2804,7 @@ \section*{Notes}
 
 Recall that my brief descriptions of the POSIX and Java APIs are no
 replacement for the official documentation on the web at
-\textit{\url{http://www.unix.org}} and \textit{\url{http://java.sun.com}}, respectively.  In particular, I claimed that each Java mutex could only be associated with a single condition variable, unlike in the POSIX API. Actually, version 1.5 of the Java API gained a second form of mutexes and condition variables, contained in the \verb|java.util.|\linebreak[0]\verb|concurrent.locks| package. These new mechanisms are not as well integrated with the Java programming language as the ones I described, but do have the feature of allowing multiple condition variables per mutex.
+\textit{\url{http://opengroup.org/unix}} and \textit{\url{http://www.oracle.com/technetwork/java/index.html}}, respectively.  In particular, I claimed that each Java mutex could only be associated with a single condition variable, unlike in the POSIX API. Actually, version 1.5 of the Java API gained a second form of mutexes and condition variables, contained in the \verb|java.util.|\linebreak[0]\verb|concurrent.locks| package. These new mechanisms are not as well integrated with the Java programming language as the ones I described, but do have the feature of allowing multiple condition variables per mutex.
 
 My spinlocks depend on an atomic exchange instruction.  I mentioned
 that one could also use some other atomic read-and-update instruction,
@@ -2903,7 +2903,8 @@ \section*{Notes}
 One example of wait-free synchronization becoming more practical is the series of papers by \index{Kogan, Alex}Kogan and \index{Petrank, Erez}Petrank~\cite{Kogan:2011:WQM:1941553.1941585,Kogan:2012:MCF:2145816.2145835} and \index{Timnat, Shahar}Timnat and \index{Petrank, Erez}Petrank \cite{Timnat:2014:PWS:2555243.2555261}.
 
 The \index{TOCTTOU}\index{Time Of Check To Time Of Use}TOCTTOU race vulnerability in Sun's mail delivery software was
-reported in 1992 by a group known as \index{eight lgm@[8lgm]}[8lgm].  Their site,
-\textit{\url{http://www.8lgm.org}}, may or may not still be around when you read
-this, but you should be able to find a copy of the advisory somewhere
+reported in 1992 by a group known as \index{eight lgm@[8lgm]}[8lgm].
+Their web site has gone offline, but the contents can
+still be accessed at the \textit{\href{https://web.archive.org/web/19961220183145/http://www.8lgm.org}{Internet Archive's ``Wayback Machine''}};
+also, you should be able to find a copy of the advisory somewhere
 on the web by searching for [8lgm]-Advisory-5.UNIX.mail.24-Jan-1992.