Starting Minecraft in offline mode crashes Java. This is because it is trying to access http://mcupdate.tumblr.com. Only when I update my routes and point to a valid webserver will it work in offline mode.

$ ./JavaApplicationStub
Bootstrap (v5)
Current time is Dec 23, 2013 7:34:04 PM
System.getProperty('os.name') == 'Mac OS X'
System.getProperty('os.version') == '10.8.5'
System.getProperty('os.arch') == 'x86_64'
System.getProperty('java.version') == '1.6.0_65'
System.getProperty('java.vendor') == 'Apple Inc.'
System.getProperty('sun.arch.data.model') == '64'

Looking for update
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 2/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 3/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 4/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 5/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 6/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 7/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 8/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 9/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Downloading: https://s3.amazonaws.com/Minecraft.Download/launcher/launcher.pack.lzma (try 10/10)
Exception: java.net.UnknownHostException: s3.amazonaws.com
Unable to download remote file. Check your internet connection/proxy settings.
Didn't find an update in time.
Reversing LZMA on /Users/tcarlson/Library/Application Support/minecraft/launcher.pack.lzma to /Users/tcarlson/Library/Application Support/minecraft/launcher.pack
Unpacking /Users/tcarlson/Library/Application Support/minecraft/launcher.pack to /Users/tcarlson/Library/Application Support/minecraft/launcher.jar
Cleaning up /Users/tcarlson/Library/Application Support/minecraft/launcher.pack
Starting launcher.
[19:34:10 ERROR]: Unexpected exception loading http://mcupdate.tumblr.com
java.net.UnknownHostException: mcupdate.tumblr.com
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:223) ~[?:1.6.0_65]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:431) ~[?:1.6.0_65]
at java.net.Socket.connect(Socket.java:527) ~[?:1.6.0_65]
at java.net.Socket.connect(Socket.java:476) ~[?:1.6.0_65]
at sun.net.NetworkClient.doConnect(NetworkClient.java:163) ~[?:1.6.0_65]
at sun.net.www.http.HttpClient.openServer(HttpClient.java:424) ~[?:1.6.0_65]
at sun.net.www.http.HttpClient.openServer(HttpClient.java:538) ~[?:1.6.0_65]
at sun.net.www.http.HttpClient.<init>(HttpClient.java:214) ~[?:1.6.0_65]
at sun.net.www.http.HttpClient.New(HttpClient.java:300) ~[?:1.6.0_65]
at sun.net.www.http.HttpClient.New(HttpClient.java:319) ~[?:1.6.0_65]
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:987) ~[?:1.6.0_65]
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:923) ~[?:1.6.0_65]
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:841) ~[?:1.6.0_65]
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1195) ~[?:1.6.0_65]
at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:379) ~[?:1.6.0_65]
at javax.swing.JEditorPane.getStream(JEditorPane.java:776) ~[?:1.6.0_65]
at javax.swing.JEditorPane.setPage(JEditorPane.java:417) ~[?:1.6.0_65]
at net.minecraft.launcher.ui.tabs.WebsiteTab$2.run(WebsiteTab.java:49) [launcher.jar:?]