How do I reflectively invoke a method with null as argument?

Question

I am trying to invoke this method in Java reflectively:

public void setFoo(ArrayList foo) { this.foo = foo; }

The problem is that

Answer 1

The compiler warning should make you aware of the problem;

The argument of type null should explicitly be cast to Object[] for the invocation of the varargs method invoke(Object, Object...) from type Method. It could alternatively be cast to Object for a varargs invocation

You can fix it like this;

Object arg = null;
method.invoke(new FooHolder(), arg);