6.4.1 Rules of the Grammar

A Serialized stream is represented by any stream satisfying the stream rule.

stream:
  magic version contents

contents:
  content
  contents content

content:
  object
  blockdata

object:
  newObject
  newClass
  newArray
  newString
  newClassDesc
  prevObject
  nullReference
  exception
  TC_RESET

newClass:
  TC_CLASS classDesc newHandle

classDesc:
  newClassDesc
  nullReference
  (ClassDesc)prevObject      // an object required to be of type
                             // ClassDesc

superClassDesc:
  classDesc

newClassDesc:
  TC_CLASSDESC className serialVersionUID newHandle classDescInfo
  TC_PROXYCLASSDESC newHandle proxyClassDescInfo

classDescInfo:
  classDescFlags fields classAnnotation superClassDesc 

className:
  (utf)

serialVersionUID:
  (long)

classDescFlags:
  (byte)                  // Defined in Terminal Symbols and
                            // Constants

proxyClassDescInfo:
  (int)<count> proxyInterfaceName[count] classAnnotation
      superClassDesc

proxyInterfaceName:
  (utf)

fields:
  (short)<count>  fieldDesc[count]

fieldDesc:
  primitiveDesc
  objectDesc

primitiveDesc:
  prim_typecode fieldName

objectDesc:
  obj_typecode fieldName className1

fieldName:
  (utf)

className1:
  (String)object             // String containing the field's type,
                             // in field descriptor format

classAnnotation:
  endBlockData
  contents endBlockData      // contents written by annotateClass

prim_typecode:
  `B'	// byte
  `C'	// char
  `D'	// double
  `F'	// float
  `I'	// integer
  `J'	// long
  `S'	// short
  `Z'	// boolean

obj_typecode:
  `[`	// array
  `L'	// object

newArray:
  TC_ARRAY classDesc newHandle (int)<size> values[size]

newObject:
  TC_OBJECT classDesc newHandle classdata[]  // data for each class

classdata:
  nowrclass                 // SC_SERIALIZABLE & classDescFlag &&
                            // !(SC_WRITE_METHOD & classDescFlags)
  wrclass objectAnnotation  // SC_SERIALIZABLE & classDescFlag &&
                            // SC_WRITE_METHOD & classDescFlags
  externalContents          // SC_EXTERNALIZABLE & classDescFlag &&
                            // !(SC_BLOCKDATA  & classDescFlags
  objectAnnotation          // SC_EXTERNALIZABLE & classDescFlag&& 
                            // SC_BLOCKDATA & classDescFlags

nowrclass:
  values                    // fields in order of class descriptor

wrclass:
  nowrclass

objectAnnotation:
  endBlockData
  contents endBlockData     // contents written by writeObject
                            // or writeExternal PROTOCOL_VERSION_2.

blockdata:
  blockdatashort
  blockdatalong

blockdatashort:
  TC_BLOCKDATA (unsigned byte)<size> (byte)[size]

blockdatalong:
  TC_BLOCKDATALONG (int)<size> (byte)[size]

endBlockData	:
  TC_ENDBLOCKDATA

externalContent:          // Only parseable by readExternal
  ( bytes)                // primitive data
    object

externalContents:         // externalContent written by 
  externalContent         // writeExternal in PROTOCOL_VERSION_1.
  externalContents externalContent

newString:
  TC_STRING newHandle (utf)
  TC_LONGSTRING newHandle (long-utf)

prevObject
  TC_REFERENCE (int)handle

nullReference
  TC_NULL

exception:
  TC_EXCEPTION reset (Throwable)object	 reset 

magic:
  STREAM_MAGIC

version
  STREAM_VERSION

values:          // The size and types are described by the
                 // classDesc for the current object

newHandle:       // The next number in sequence is assigned
                 // to the object being serialized or deserialized

reset:           // The set of known objects is discarded
                 // so the objects of the exception do not
                 // overlap with the previously sent objects 
                 // or with objects that may be sent after 
                 // the exception