Clarifications/Suggestions in Java

Question

1> I have a Employee class with six employee objects{e1,e2,e3,e4,e5,e6} added to it.How do i sort it using Tree Set ?Code example please
2> What is load factor in HashMap.?
3> Can i subclass a singleton class ?
4> what is lazy loading of Servlets ?
5> how do you intialize a session in Servlets ?
6>what is the pros and cons os using jsp:use bean tag
7> give an example where you can use DynaActionForm.Code example please                                                                                         Please help

Answer 1

1> I have a Employee class with six employee objects{e1,e2,e3,e4,e5,e6} added to it.How do i sort it using Tree Set ?
Employee e1 = new Employee();
Employee e2 = new Employee();
Employee e3 = new Employee();
Employee e4 = new Employee();
Employee e5 = new Employee();
Employee e6 = new Employee();
SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...)); // i dont know how to proceed at this step.Please help me now.2> What is load factor in HashMap.?
An instance of HashMap has two parameters that affect its performance: initial capacity and load factor. The capacity is the number of buckets in the hash table, and the initial capacity is simply the capacity at the time the hash table is created. The load factor is a measure of how full the hash table is allowed to get before its capacity is automatically increased. When the number of entries in the hash table exceeds the product of the load factor and the current capacity, the hash table is rehashed (that is, internal data structures are rebuilt) so that the hash table has approximately twice the number of buckets.
As a general rule, the default load factor (.75) offers a good tradeoff between time and space costs. Higher values decrease the space overhead but increase the lookup cost (reflected in most of the operations of the HashMap class, including get and put). The expected number of entries in the map and its load factor should be taken into account when setting its initial capacity, so as to minimize the number of rehash operations. If the initial capacity is greater than the maximum number of entries divided by the load factor, no rehash operations will ever occur. 3> Can i subclass a singleton class ?
I have not tried but i *think* we cannot subclass a singleton class.Need example for this .
4> what is lazy loading of Servlets ?
A container doesnot initialize the servlets as soon as it starts up, it initializes a servlet when it receives a request for that servlet first time. This is called lazy loading. The servlet specification defines the <load-on-startup> element, which can be specified in the deployment descriptor to make the servlet container load and initialize the servlet as soon as it starts up. The process of loading a servlet before any request comes in is called preloading or preinitializing a servlet.5> how do you intialize a session in Servlets ?
  HttpSession session  = request.getSession(); //please correct me if im wrong. 6> give an example where you can use DynaActionForm --> Please help me with this..