The only relatively fast way to count the size of the object is to first write the whole object, count the usage (for example, write to a ByteArrayOutputStream) and then write each object that is referred to. There are a couple of this to take into account:. The ObjectOutputStream does do some caching to be able to refer to a previously written object with a simple pointer. Use the reset method to clear this cache.
Each new object type that is written, first has the class description. The overhead of this depends on the number of same-type objects that you are referring to. There is a (small, 4-byte) overhead to initialize the ObjectOutputStream. For the description of the protocol, read.
If you want to test serialization, then write tests that do the following: Serialize one object to a file. Deserialize to a different object from the same file.
To serialize an object means to convert its state to a byte stream so that the byte stream can be reverted back into a copy of the object. A Java object is serializable if its class or any of its superclasses implements either the java.io.Serializable interface or its subinterface, java.io.Externalizable.
Deserialization is the process of converting the serialized form of an object back into a copy of the object. For example, the java.awt.Button class implements the Serializable interface, so you can serialize a java.awt.Button object and store that serialized state in a file. Later, you can read back the serialized state and deserialize into a java.awt.Button object. The Java platform specifies a default way by which serializable objects are serialized. A (Java) class can override this default serialization and define its own way of serializing objects of that class. The describes object serialization in detail.
When an object is serialized, information that identifies its class is recorded in the serialized stream. However, the class's definition ('class file') itself is not recorded.
It is the responsibility of the system that is deserializing the object to determine how to locate and load the necessary class files. For example, a Java application might include in its classpath a JAR file that contains the class files of the serialized object(s) or load the class definitions by using information stored in the directory, as explained later in this lesson. Binding a Serializable Object You can store a serializable object in the directory if the underlying service provider supports that action, as does Oracle's LDAP service provider.
![Free file viewer download Free file viewer download](http://condor.depaul.edu/ntomuro/courses/224/notes/figs/swing-filechooser.jpg)
The following example invokes to bind an AWT button to the name 'cn=Button'. To associate attributes with the new binding, you use. To overwrite an existing binding, use and.
# java SerObj java.awt.Buttonbutton0,0,0,0x0,invalid,label=Push me Specifying a Codebase Note: The procedures described here are for binding a serializable object in a directory service that follows the schema defined in. These procedures might not be generally applicable to other naming and directory services that support binding a serializable object with a specified codebase. When a serialized object is bound in the directory as shown in the previous example, applications that read the serialized object from the directory must have access to the class definitions necessary to deserialize the object.
Alternatively, you can record a codebase with the serialized object in the directory, either when you bind the object or subsequently by adding an attribute by using. You can use any attribute to record this codebase and have your application read that attribute from the directory and use it appropriately.
![Serialized Serialized](https://flylib.com/books/1/134/1/html/2/images/javaio2_2503.jpg)
Or you can use the 'javaCodebase' attribute specified in. In the latter case, Oracle's LDAP service provider will automatically use the attribute to load the class definitions as needed. 'javaCodebase' should contain the URL of a codebase directory or a JAR file. If the codebase contains more than one URL, then each URL must be separated by a space character.
The following example resembles the one for binding a java.awt.Button. It differs in that it uses a user-defined Serializable class, and supplies a 'javaCodebase' attribute that contains the location of Flower's class definition.
Here's the code that does the binding.