没有泛型之前 Object为最上层的父类别,所以用它来实现 泛型( Generics)功能 public class objectFoo private object fooi public void set Foo(object foo) f this. foo foo public objectgetFoo() return foo没有泛型之前 public class ObjectFoo { private Object foo; public void setFoo(Object foo) { this.foo = foo; } public ObjectgetFoo() { return foo; } } • Object为最上层的父类别，所以用它来实现 泛型（Generics）功能