May i know wat are u trying to achieve here?Btw,u may like to check out Quartz,a Java scheduler...I don't really like to write my own thread unless its really necessary...usually i will use Quartz other other open source tools to ease my work,plus i m a web based programmer,so multithread isnt much of my concern as servlet or j2ee is already multithreaded...
if u plan to use quartz,i can give u some advice on ur situation,put ur section of code that u wish to re-run in a class and add this class into ur quartz schedule,then write another apps to start only the quartz scheduler(please refer to quartz website for this) and thats it...try to run the apps for couple of days without shuhtting down the apps,if the memory running low means ur java coding got memory leaking problem,review ur code and optimize it,if the problem still occurs,write another scheduler job to run GC...happy coding...