Limit hd quota and memory usage by user at linux

Hello i need limit hd quita and memory usage by user whats the best way to do this? for example: lets supose i have a server with 4gb ram and 40gb hd, i want share all resources with 4 users, so each one must have garanteed 1gb ram (can use more if are avaiable) and use max 10gb hd. how can i do

Instal sun java 1.5 jdk or jre and tomcat 5.5.25

hello, im new in at linux administration, i have to install java (1.5 [jre or jdk] ) and tomcat 5.5.25 Can anyone help me? Any goot step-step guide? I just try search at google bur not sucess. Thanks in advanced