How to retrieve the type of content used for a Collection

If you need to know what is defined for each generic type in your instance use the following piece of code

Code:

Method method = myClass.getMethod("getCalendars", null);

Type returnType = method.getGenericReturnType();

if (returnType instanceof ParameterizedType) {

ParameterizedType type = (ParameterizedType) returnType;

Type[] typeArguments = type.getActualTypeArguments();

for (Type typeArgument : typeArguments) {

Class typeArgClass = (Class) typeArgument;

System.out.println("typeArgClass = " + typeArgClass);

}

}

Comments:

1) myClass is the class that has a method named "getCalendars" which returns an instance of a class that uses generics.

2) You can try it by implementing a class that returns a "java.util.List"

source: http://tutorials.jenkov.com/java-reflection/generics.html#parametertypes