ObjectOutputStream writeObject(Object) in Java

writeObject(Object): This method is available in the java.io.ObjectOutputStream class of Java.

Syntax:

void java.io.ObjectOutputStream.writeObject(Object obj) throws IOException

This method takes one argument. This method writes the specified object to the ObjectOutputStream. The class of the object, the signature of the class, and the values of the non-transient and non-static fields of the class and all of its super types are written.

Parameters: One parameter is required for this method.

obj: the object to be written.

Returns: NA

Throws:

1. InvalidClassException - Something is wrong with a class used by serialization.

2. NotSerializableException  - Some object to be serialized does not implement the java.io.Serializable interface.

3. IOException - Any exception thrown by the underlying OutputStream.

Approach

Java

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;

public class ObjectOutputStreamwriteLong {
    public static void main(String[] args) throws IOException {

        FileOutputStream fileStream = new FileOutputStream("D:\\hello.txt");

        ObjectOutputStream objStream = new ObjectOutputStream(fileStream);

        long val = 1000101001L;
        objStream.writeLong(val);
        System.out.println("Successfully writes long to the stream");

        objStream.close();
    }
}

Output:

Successfully writes the object to the stream

Some more methods of ObjectOutputStream

close(): This method must be called to release any resources associated with the stream.

defaultWriteObject(): This method writes the non-static and non-transient fields of the current class to this stream.

flush(): This method flushes the stream.

putFields(): This method retrieves the object used to buffer persistent fields to be written to the stream.

reset(): The state is reset to be the same as a new ObjectOutputStream.

useProtocolVersion(int): This method specifies the stream protocol version to use when writing the stream.

write(byte[]): This method writes an array of bytes. 

write(int): This method writes a byte.

write(byte[], int, int): This method writes a sub array of bytes.

writeBoolean(boolean): This method writes a boolean.

writeByte(int): This method writes an 8-bit byte.

writeBytes(String): This method writes a String as a sequence of bytes.

writeChar(int): This method writes a 16-bit char.

writeChars(String): This method writes a String as a sequence of chars.

writeDouble(double): This method writes a 64-bit double.

writeFields(): This method writes the buffered fields to the stream.

writeFloat(float): This method writes a 32-bit float.

writeInt(int): This method writes a 32-bit int.

writeLong(long): This method writes a 64-bit long.

writeShort(int): This method writes a 16-bit short.

writeUnshared(Object): This method writes an "unshared" object to the ObjectOutputStream.

writeUTF(String): This method is primitive data are written of this String in modified UTF-8 format.