git clone https://github.com/vernetto/springdemo.git
git checkout v001 // plain vanilla helloworld
git checkout v002 // lazy init
git checkout v003 // 2 beans, singleton
git checkout v004 // 2 beans, prototype
git checkout v005 // init method
git checkout v006_1 // destroy not working
git checkout v006_2 // destroy still not working
git checkout v006_3 // destroy working
git checkout v006_4 // destroy with DisposableBean