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CSE205 Lecture 25

CSE205 Lecture 25

Object-Oriented Programming and Data Structures
Serialization and Final Review
(202204)

Javier Gonzalez-Sanchez
PRO

October 05, 2021
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    CSE 205
    Object-Oriented Programming and
    Data Structures
    Lecture 25: Serialization
    Dr. Javier Gonzalez-Sanchez
    [email protected]
    javiergs.engineering.asu.edu | javiergs.com
    PERALTA 230U
    Office Hours: By appointment

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  2. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 2
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    Exceptions
    There are many exception types available in Java:
    § ArithmeticException,
    § FileNotFoundException,
    § ArrayIndexOutOfBoundsException,
    § SecurityException,
    § etc.
    § The parent of all is the class Exception

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    Example

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    finally Statement
    § The finally statement lets you execute code, after try...catch,
    regardless of the result

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    Example

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    throw

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    Definition
    § The throw statement allows you to create a custom error

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    Example

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    Example

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    Serialization

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    I/O Streams
    § An I/O Stream represents an input source or an output destination

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    BufferedReader
    PrintWriter
    I/O Streams
    binary
    FileInputStream
    FileOutputStream
    FileReader
    FileWriter
    char
    FileReader
    FileWriter
    lines

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    Serialization
    § Java provides a mechanism, called serialization where an object can be
    represented as a sequence of bytes that includes the object's data as well
    as information about the object's type and the types of data stored in the
    object.

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  15. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 15
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    I/O Streams
    BufferedReader
    PrintWriter
    binary
    FileInputStream
    FileOutputStream
    FileReader
    FileWriter
    char
    FileReader
    FileWriter
    lines
    ObjectInputStream
    ObjectOutputStream
    FileInputStream
    FileOutputStream
    objects

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  16. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 16
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    Serialization
    § the process is JVM independent –an object can be serialized on one
    platform and deserialized on an entirely different platform.
    § Classes ObjectInputStream and ObjectOutputStream are high-level
    streams that contain the methods for serializing and deserializing an object.

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  17. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 17
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    Step 1

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    Serializable
    For a class to be serialized, two conditions must be met:
    § The class must implement the java.io.Serializable interface.
    § All the fields in the class must be serializable.
    § If you do not want a field to be serializable, mark is as transient, such as
    public transient int grade;

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    Step 2

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    Step 3

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  21. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 21
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    Serialization
    § The try/catch block tries to catch a ClassNotFoundException, which is
    declared by the readObject() method.
    § For a JVM to be able to deserialize an object, it must be able to find the
    bytecode for the class. If the JVM can't find a class during the
    deserialization of an object, it throws a ClassNotFoundException.
    § Notice that the return value of readObject() is an Object. Thus, casting is
    needed.

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    Topics to Review

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    Topics per Week

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    The following slides shows some examples
    related to some topics
    This is NOT a comprehensive list of topics
    Topics in the exam can be found
    Weeks 2 to 16
    (Lectures 1 to 24)

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  26. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 26
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    Questions

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    CSE 205 Object-Oriented Programming and Data Structures
    Javier Gonzalez-Sanchez, Ph.D.
    [email protected]
    Fall 2021
    Copyright. These slides can only be used as study material for the class CSE205 at Arizona State University.
    They cannot be distributed or used for another purpose.

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