A question about Java serialization, see how much you know ————

Here's the question, and I'll answer it later.

Known classes have test and Test2, ask two times what the output of the main program (Serializeutil is just a serialized tool class)

Class Test

 Public classTestImplementsserializable{Private Static Final LongSerialversionuid = 1L; Private intnum; Private transientString str;  PublicTest () { This. num = 0xFFFF;  This. str = "string"; }     PublicTest (intnum, String str) {         This. num =num;  This. str =str; } @Override PublicString toString () {returnnum + "," +str; }}

Class Test2

 Public classTest2Implementsexternalizable,serializable{Private Static Final LongSerialversionuid = 1L; Private intnum; Private transientString str;  PublicTest2 () { This. num = 0xFFFF;  This. str = "Hello"; }     PublicTest2 (intnum, String str) {         This. num =num;  This. str =str; } @Override Public voidWriteexternal (ObjectOutput out)throwsioexception {out.write (num); } @Override Public voidReadexternal (ObjectInput in)throwsIOException, ClassNotFoundException { This. num =In.read (); } @Override PublicString toString () {returnnum + "," +str; }}

Two main programs:

     Public Static void Main (string[] args) {        new  Test ();         New File ("D:/test.bin");        Serializeutil.writeobject (file,test);         = (Test) serializeutil.readobject (file);        SYSTEM.OUT.PRINTLN (test);        System.out.println (test2);    }

     Public Static void Main (string[] args) {        new  Test2 ();         New File ("D:/test2.bin");        Serializeutil.writeobject (FILE,TEST2);         = (Test2) serializeutil.readobject (file);        System.out.println (test2);        System.out.println (t);    }

The code attached to Serializeutil can be ignored--

1  Public classSerializeutil {2 3      Public Static voidwriteobject (File file,object Object) {4FileOutputStream FileOutputStream =NULL;5         Try {6FileOutputStream =Newfileoutputstream (file);7ObjectOutputStream ObjectOutputStream =NewObjectOutputStream (fileoutputstream);8 Objectoutputstream.writeobject (object);9 Objectoutputstream.flush ();Ten}Catch(IOException e) { One e.printstacktrace (); A}finally { -             if(fileoutputstream!=NULL){ -                 Try { the fileoutputstream.close (); -}Catch(IOException e) {} -             } -         } +     } -  +      Public StaticObject readobject (file file) { AFileInputStream FileInputStream =NULL; at         Try { -FileInputStream =Newfileinputstream (file); -ObjectInputStream ObjectInputStream =NewObjectInputStream (fileinputstream); -             returnObjectinputstream.readobject (); -}Catch(classnotfoundexception|IOException E) { - e.printstacktrace (); in}finally { -             if(fileinputstream!=NULL){ to                 Try { + fileinputstream.close (); -}Catch(IOException e) {} the             } *         } $         return NULL;Panax Notoginseng     } -  the}

Serialization Tool Class

The answers are as follows:

/* First Main program: 65535,string65535,null the second main program: 65535,hello255,hello */

Answer

A question about Java serialization, see how much you know ————