What is ObjectInputStream Class In Java ?

Class ObjectInputStream

All Implemented Interfaces:

Closeable, DataInput, ObjectInput, ObjectStreamConstants, AutoCloseable

Declaration of ObjectInputStream:

public class ObjectInputStream

extends InputStream

implements ObjectInput, ObjectStreamConstants

ObjectInputStream class (java.io.ObjectInputStream) enables you to read Java objects from an InputStream . We wrap an InputStream in a ObjectInputStream and then you can read objects from it. Implementing the Serializable interface allows object serialization to save and restore the entire state of the object.

Normally you will use the ObjectInputStream to read objects written (serialized) by a Java ObjectOutputStream .

Only objects that support the java.io.Serializable or java.io.Externalizable interface can be read from streams.

The method readObject is used to read an object from the stream. Java's safe casting should be used to get the desired type. 

The default deserialization mechanism for objects restores the contents of each field to the value and type it had when it was written. 

Fields declared as transient or static are ignored by the deserialization process.

Constructor Summary of ObjectInputStream:

Constructor	Description
ObjectInputStream()	Provide a way for subclasses that are completely reimplementing ObjectInputStream to not have to allocate private data just used by this implementation of ObjectInputStream.
ObjectInputStream(InputStream in)	Creates an ObjectInputStream that reads from the specified InputStream.

Method Summary of ObjectInputStream:

Modifier	Method Name	Description
int	available()	Returns the number of bytes that can be read without blocking.
void	close()	Closes the input stream.
void	defaultReadObject()	Read the non-static and non-transient fields of the current class from this stream.
protected Boolean	enableResolveObject(boolean enable)	Enable the stream to allow objects read from the stream to be replaced.
int	read()	Reads a byte of data.
int	read(byte[] buf, int off, int len)	Reads into an array of bytes.
boolean	readBoolean()	Reads in a boolean.
byte	readByte()	Reads an 8 bit byte.
char	readChar()	Reads a 16 bit char.
protected ObjectStreamClass	readClassDescriptor()	Read a class descriptor from the serialization stream.
double	readDouble()	Reads a 64 bit double.
ObjectInputStream.GetField	readFields()	Reads the persistent fields from the stream and makes them available by name.
float	readFloat()	Reads a 32 bit float.
void	readFully(byte[] buf)	Reads bytes, blocking until all bytes are read.
void	readFully(byte[] buf, int off, int len)	Reads bytes, blocking until all bytes are read.
int	readInt()	Reads a 32 bit int.
String	readLine()	Deprecated. This method does not properly convert bytes to characters. see DataInputStream for the details and alternatives.
long	readLong()	Reads a 64 bit long.
Object	readObject()	Read an object from the ObjectInputStream.
protected Object	readObjectOverride()	This method is called by trusted subclasses of ObjectOutputStream that constructed ObjectOutputStream using the protected no-arg constructor.
short	readShort()	Reads a 16 bit short.
protected void	readStreamHeader()	The readStreamHeader method is provided to allow subclasses to read and verify their own stream headers.
Object	readUnshared()	Reads an "unshared" object from the ObjectInputStream.
int	readUnsignedByte()	Reads an unsigned 8 bit byte.
int	readUnsignedShort()	Reads an unsigned 16 bit short.
String	readUTF()	Reads a String in modified UTF-8 format.
void	registerValidation(ObjectInputValidation obj, int prio)	Register an object to be validated before the graph is returned.
protected Class<?>	resolveClass(ObjectStreamClass desc)	Load the local class equivalent of the specified stream class description.
protected Object	resolveObject(Object obj)	This method will allow trusted subclasses of ObjectInputStream to substitute one object for another during deserialization.
protected Class<?>	resolveProxyClass(String[] interfaces)	Returns a proxy class that implements the interfaces named in a proxy class descriptor; subclasses may implement this method to read custom data from the stream along with the descriptors for dynamic proxy classes, allowing them to use an alternate loading mechanism for the interfaces and the proxy class.
int	skipBytes(int len)	Skips bytes.

      

Blog Author - Pushkar Khosla,
Software Developer by Profession with 3.0 Yrs of Experience , through this blog i'am sharing my industrial Java Knowledge to entire world. For any question or query any one can comment below or mail me at pushkar.itsitm52@gmail.com.