Java generics why can't I instantiate a genericized type [duplicate]

Question

I was writing something using generics and to my surprise I found that this doesn't work:

class foo<T>{

 T innerT = new T();

}

So can't I instantiate the genericized type? Aren't there any ways to do this?

Answer 1

At the runtime JVM doesn't know what T is so it can't create new object of type T. Types are erased during compilation.

Answer 2

Yeah, it's pretty damn annoying.

The work around I use is to force the client to pass the class in when constructing a new foo<T> - i.e.

public foo(Class<T> myClass)

Then you can use myClass.newInstance() instead.