.Net inbuilt classes - Interfaces

Below are the .Net inbuilt classes and each class is inheriting from different interfaces... At glance please look into the below sample classes..

public class Tuple<T1> : IStructuralEquatable, IStructuralComparable, IComparable, ITuple

public sealed class String : IComparable, ICloneable, IConvertible, IComparable<string>, IEnumerable<char>, IEnumerable, IEquatable<string>

public class SystemException : Exception

public sealed class StringBuilder : ISerializable

public abstract class StringComparer : IComparer, IEqualityComparer, IComparer<string>, IEqualityComparer<string>

public abstract class Stream : MarshalByRefObject, IDisposable

public class Hashtable : IDictionary, ICollection, IEnumerable, ISerializable, IDeserializationCallback, ICloneable

public class ArrayList : IList, ICollection, IEnumerable, ICloneable

public class SortedList : IDictionary, ICollection, IEnumerable, ICloneable

public class Stack : ICollection, IEnumerable, ICloneable