Ever since v1.4, this "Software caused connection abort: recv failed" error started happening on a fairly regular basis.

It seemed to be happening in areas containing excessive mobs, which probably contributes to the issue, due to network activity. However, the error does not appear to be related to the operation of the game at all, but related to a threaded background process, that checks your servers for a flag that an updated version is available.

Simply trapping for this error will make a tremendous number of people happy. I can't count the number of people who have been complaining about this very error, with no clue why it's happening.

There is no exception created when this happens. The client simply throws up the error message on the screen and allows you to return to the main menu. However, I run my Minecraft with a batch file that kicks Java off with additional memory activated. So I see the exception text come across in that window and have copied-n-pasted it below.

java.net.SocketException: Software caused connection abort: recv failed
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.read(Unknown Source)
        at java.net.SocketInputStream.read(Unknown Source)
        at java.io.FilterInputStream.read(Unknown Source)
        at ei.a(SourceFile:185)
        at ci.i(SourceFile:250)
        at ci.c(SourceFile:16)
        at cj.run(SourceFile:94)

java.io.FileNotFoundException: http://assets.minecraft.net/1_6_has_been_released.flag
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
        at kn.a(SourceFile:234)
        at bkg.run(SourceFile:113)
        at java.lang.Thread.run(Unknown Source)