The main purpose is that if we have to use a resource then we can create a singleton class which can only access the resource and by making this instance available to other threads or any part of the application we can make sure that unnecessary objects are not getting created for accessing the resource.
Another purpose is that we have some utility classes which are being used by other java classes to do some calculations etc. Now if we make the utility class a singleton class then all objects and all parts of the application can use this one instance of the utility class and no extra instaces are required. There are lots of other uses also.
Static types -- most programmers love them or hate them. Advocates boast that static types allow them to produce cleaner and more reliable code than they could without them. Detractors moan about the added complexity that static types require of a program.
This chapter provides tutorial notes on downloading, installing and setting up Java DB (Derby) server. Topics include downloading and installing Java DB 10.2.2; verifying Java DB execution environment; running Java DB in Network Server mode; using 'ij' to create database and tables.
server-side control architectures such as Java ServerFaces (JSF) or Struts, a majority of the control events must be handled on the server side to update the state of the control. For every user event, the entire page data is sent back to the server as part of the form submission. Even data that has not changed or is not affected by the user event is sent to (and back from) the server. It is obvious that handhelds, overburdened Web servers, and possibly wireless networks would benefit from the avoidance of redundant data processing in these instances; the question is how to implement a solution.
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