Added a property, java.net.namelookup.cache that may be set to an int representing the number of seconds for which to cache a lookup. 0 is no cache, -1 is cache forever (the current default).




When a host name is unresolved, the InetAddress class
actually stores this fact in its cache.
This is a problem for an application if the host name becomes available
while the application is running and after a InetAddress.getByName() has
already been unsuccessfully performed:
The application will never be able to use the hostname address, although
it can be resolved now.

Is this still the same with JDK 1.1 ? I didn't found the class sources
in the 1.1 Beta.
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None, restarting the application is required.
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Added a property in 1.2 to control the caching of namelookups: java.net.namelookup.cache. See java.net.InetAddress.

 xxxxx@xxxxx  1998-04-28

Real problem in networks without nameserver 
connected to the internet only over a dial-up 
connection. Hostnames can't be resolved any more
if a hostname lookup fails, before the connection
is established.

this is a problem when your application is a servlet.
How can your restart it?
and How can you know that it stopped?

I tried to use the property described above to 
get around this problem without success:
    java -Djava.net.namelookup.cache=0 ...
I'm using Java v1.2.2, is the property still
valid for this version?

This bug is not fixed, it still appears in 1.2.1 final release.
When using dial-up connection this is an unacceptable problem
that render all network classes unusable.
What is the java.net.namelookup.cache ? There is not such
property at all.

After some research into the sources of jdk 1.2.1
This seem to toggle the caching policy in jdk 1.2.1:
java -Dsun.net.inetaddr.ttl=0
this is the property that the sun.net.InetAddressCachePolicy
is using and which in turn are used by java.net.InetAddress.

In jdk.1.2.2, is there an equivalent variable setting to 
clear the UnknownHostException?  I'm not able to clear an 
UnknownHostException without exiting the application.  For 
example, if the application starts with the phone cord 
disconnected, then after getting the UnknownHostException, 
and reconnecting the cable, it continues to give the 
exception.

THIS IS NOT FIXED!

YOU ARE BREAKING THE INTERNET STANDARDS ON DNS - You *MUST 
NOT* permanently cache DNS results - there is NO POINT in 
the DNS system if you are going to do this.

Please re-open this bug until you have properly fixed it 
(CHANGE THAT DEFAULT BEHAVIOUR!)

How has this changed in 1.3 and 1.4?  I see that the 1.4 
API docs mention networkaddress.cache.ttl and 
networkaddress.cache.negative.ttl.  Do these two parameters 
override the sun.net.inetaddr.ttl parameter from 1.2?

I'm having this problem using version 1.3.x, but not using 
version 1.4.x
Is there a work around for this InetAddress cache problem?
Please any one...this would be great help.

Is this bug related to 624750? 
There seem to be various issues surrounding the lack of honoring networkaddress.cache.ttl.