Externalization serves the
purpose of custom Serialization
, where we can decide what to store in stream. Externalizable interface present in java.io, is used for Externalization which extends Serializable interface. It consist of two methods which we have to override to write/read object into/from stream which are-
Why do we use externalization in Java?
Externalization is used
whenever we need to customize serialization mechanism
. If a class implements an Externalizable interface then, object serialization will be done using writeExternal() method.
Why do we need externalization in Java?
Externalization in Java is
used to customize the serialization mechanism
. Java serialization is not much efficient. When we have bloated objects that hold several attributes and properties, it is not good to serialize them. Here, the externalization will be more efficient.
What is purpose of Externalizable interface?
io. Externalizable interface. The main goal of this interface is
to facilitate custom serialization and deserialization
.
What is serialization and externalization?
Serialization and externalization both are
the processes of converting an object to stream byte and storing byte stream in database or memory
. The class which implements java. … On the other hand, externalization used for custom serialization based on the requirement in the application. Externalization extends java.
What is true serialization?
Serialization
provides a way where an object can be represented as a sequence of bytes
which includes the object’s data and information having the object’s type and the types of data stored in the object. It can only be read from the file after the serialized object is written into a file.
What is serialization used for?
Serialization is the process of converting an object into a stream of bytes to store the object or transmit it to memory, a database, or a file. Its main purpose is
to save the state of an object in order to be able to recreate it when needed
. The reverse process is called deserialization.
What is advantage of serialization in Java?
Serialization
allows us to transfer objects through a network by converting it into a byte stream
. It also helps in preserving the state of the object. Deserialization requires less time to create an object than an actual object created from a class. hence serialization saves time.
What is the meaning of externalization?
the act of expressing feelings, especially bad feelings such as anger, or something that expresses these feelings: the externalization of
negative feelings
.
Is Externalizable a marker interface?
The
externalizable interface is not a marker interface
and thus it defines two methods writeExternal() and readExternal(). Serializable interface passes the responsibility of serialization to JVM and the programmer has no control over serialization, and it is a default algorithm.
Why do we need SerialVersionUID in Java?
The SerialVersionUID can be used
during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible w.r.t serialization
. If the deserialization object is different than serialization, then it can throw an InvalidClassException.
What is transient in Java?
transient is
a variables modifier used in serialization
. At the time of serialization, if we don’t want to save value of a particular variable in a file, then we use transient keyword. When JVM comes across transient keyword, it ignores original value of the variable and save default value of that variable data type.
What is readResolve method in Java?
The readResolve method is called when
ObjectInputStream has read an object from the stream and is preparing to return it to the caller
. … If the method is defined, the readResolve method is called to allow the object in the stream to designate the object to be returned.
What is difference between serialization and Deserialization in Java?
Serialization is a mechanism of converting the state of an object into a byte stream. Deserialization is the
reverse process
where the byte stream is used to recreate the actual Java object in memory. … So, the object serialized on one platform can be deserialized on a different platform.
What is difference between serializable and Parcelable?
Serializable is a standard Java interface. You simply mark a class Serializable by implementing the interface, and Java
will
automatically serialize it in certain situations. Parcelable is an Android specific interface where you implement the serialization yourself.
How is custom serialization implemented in Java?
- Inside writeObject() method, write class attributes using writeXXX methods provided by ObjectOutputStream .
- Inside readObject() method, read class attributes using readXXX methods provided by ObjectInputStream .
