I dont think its the threads which are a problem. You have a memory leak I believe. Also, its possible that you just need more memory for the java process (tomcat instance i.e.)
1. You need to put the user credentials in session and remove them from the session at logout. When a page is rendered, you need to check if the credentials are still in the session
DO these 3 mocks also give us a good idea of how much we can expect to score in the real exam? I skipped the ones which are not in scjp 1.4... or should i use some other 1.4 specific ones?