Best Practice Needed: Global Application Properties...

Question

Hi All,
When developing a web-based application that reads certain configurable parameters from .properties files, I usually put the appropriate code in a static block in the appropriate Java class, storing the property in a static final constant. For example, a DBConnection class might have a static block that reads the driver, username, and password from a properties file.
My question is, what are some "best practice" techniques for accessing and storing such parameters for use in an application? Are all global properties initialized in one class? at the same time? only when first needed?

Answer 1

over all, I would say that your approach is fine. Personally, I load properties through a single class, some thing like PropertyReader, and have the different classes initialize their static fields via a get method on that class, like getProperty("db.user"). I prefer to load them via a single class because I can place all of my IO trapping in one location, it is easier to implement new security measures and, if necessary, easier to support internationalization.
I initialize all properties once, at startup, into a Wrapper Object, typically ResourceBundle or Properties (although Hashtable or any some thing else would be suitable). I believe that it is best to initialize all properties at the same time, at startup because the costs of storing properties that may not be used is going to be less then the cost of making multiple IO calls to load properties on a need-by-need basis. In other words, you are almost always going to take a bigger performance hit by loading properties only when a request for that key is received, rather then just loading them all at once.