With process explorer (graphical taskmanager) I can see the processes launched
by Hudson.

I see:
+ Hudson-slave.exe
+ java.exe (which is the actual slave)
+ java.exe "C:\Program Files\Java\jdk1.6.0_10\bin\java" -Xmx256m -cp
E:\hs\maven-agent.jar;E:\apache-maven-2.0.9\boot\classworlds-1.1.jar
hudson.maven.agent.Main E:\apache-maven-2.0.9 E:\hs\slave.jar
E:\hs\maven-interceptor.jar 2980
+ java exe "C:\Program Files\Java\jdk1.6.0_10\bin\java" -Xmx256m -cp
E:\hs\maven-agent.jar;E:\apache-maven-2.0.9\boot\classworlds-1.1.jar
hudson.maven.agent.Main E:\apache-maven-2.0.9 E:\hs\slave.jar
E:\hs\maven-interceptor.jar 4013

Both java.exe subprocesses keep alive even when not builder is active anymore.
When changing classpath or environment variable these builders do not get
updated. Also a new settings.xml for Maven is not picked up.
We already noticed once that these runners caused unsuspected issues, but to the
fact that they where out of sync. Restarting the slave solved that issues.

Both processes consume 200+MB memory just by doing nothing.

I my opinion, when idle, these processes should get killed.

See attachment for a graphical view