Do i need both Java 5.0 and Java 6....?

Ok, here is the details to my question, i have in my add and remove programs both 'J2SE Runtime Environment 5.0 update 2' and 'Java(TM) 6 update 16', i have wondered this for awhile but never came to ask in here, i always tried and google it but never find a legitimate answer. So anyway, i notice both javas when i run hijackthis and look in files and folders, but for example, when i run hijackthis it shows all types of java aplications, i mean the 5 and 6 but theres like 4 or 5 different areas there in. Ok, so my main question which is long overdue and sorry for that but i need to know do i need BOTH Java programs i mentioned in the beginning of this message. I really dont think i do, but im just afraid if i get rid of the 5.0 then some programs wont run right or at all. I need to know not only if i need both but if the Java 6 will take over for all programs that use the 5.0 if that makes any sense. Ok, so any feedback would be great and much appreciation to anybody that responds to my question. Thanks in advance and hope to hear something soon, haha.