Serializable

• Objects that are written to an object stream must belong to a class
  that implements the Serializable interface.

  class BankAccount implements Serializable
  {
     . . .
  }

• Serializable interface has no methods.
• Serialization: process of saving objects to a stream
  • Each object is assigned a serial number on the stream
  • If the same object is saved twice, only serial number is written out the second time
  • When reading, duplicate serial numbers are restored as references to the same object