• JUnit

• Sun.TutorialGenerics are a purely compile time feature.
  • Generics, an advanced feature of Java 1.5, allow type checking to make sure you fill your Collections and ArrayLists with only the types of Object you intend.
  • All of the Java Collection classes (e.g., HashMap, ArrayList, and TreeList) only contain generic Objects.
  • Java 1.5 compiler performs implicit casts on generics both on the way into the collection and on the way out. This is done so to let the programmer avid casting in his code.
  • Removing the cast from inplementation of generics would create a vulnerability in the JVM that could be exploited maliciously.
• Autoboxing: when Java expects an object but receives a primitive type, it converts that primitive type to an object; int primitive is converted to Integer object, for example.
• Another feature lacking in Java before version 1.5 is variable-length argument lists. These arguments are resolved as a primitive Array.

public class DocumentManager<TDocument>
   where TDocument:IDocument
{...}

public delegate TSummary Action<TInput, TSummary>(TInput t, TSummary u);

public static TSummary Accumulate<TInput, TOutput>(IEnumerable<T> coll, Action<TInput, TSummary> action)
{
           TSummary sum = default(TSummary);
           foreach (TInput input in coll )
          {
                sun = action(input, sum);
          }
          return sum;
}
// then invoke the method as follows:

decimal amount = Accumulate<Account, decimal>(
               accounts, delegate(Account a, decimal d){ return a.Balance + d;} ) ;