Life time of the java MAP

Question

I want a map / list in my java application that should remain in memory until the lifetime of the application. Suppose if the application's life time is1 year then the specified MAP should also remain in memory for 1 year. I am using JDK1.3.
In jdk1.4 sun micro systems has added the facility of Prefrences there we can set our application or system prefrences But I want to implement it in JDK1.3
Please Help me how i can implement this idea. I will be very thankful to you

Answer 1

Hello abdulqadeerbasit,
you could use a singleton pattern :
public class Storage {
     static java.util.Map map;
     static {     //this block will be executed once after classloading of Storage
          initStorage();
     private void initStorage() {
          map = new java.util.HashMap();
          // fill map
          map.put("key", "value");
     public java.util.Map getStorage() {
          return map;
If you call getStorage() the class loader loads it and therefore initializes your map. This map will be in memory till your application stops. You should avoid concurrent modifications (use synchronize).