What does the transient keyword do?

What does the transient keyword do?

The transient keyword in Java is used to avoid serialization. If any object of a data structure is defined as a transient , then it will not be serialized. Serialization is the ​process of converting an object into a byte stream.

What is transient variable in Java with example?

transient variable in Java is a variable whose value is not serialized during Serialization and which is initialized by its default value during de-serialization, for example for object transient variable it would be null.

How do you declare a transient variable in Java?

PersistExample.java

1. import java.io.*;
2. public class Student implements Serializable{
3. int id;
4. String name;
5. transient int age;//Now it will not be serialized.
6. public Student(int id, String name,int age) {
7. this.id = id;
8. this.name = name;

Why entry table is transient in HashMap?

HashMap uses writeObject and readObject to implement custom serialization rather than just letting its field be serialized normally. It writes the number of buckets, the total size and each of the entries to the stream and rebuilds itself from those fields when deserialized.

How do I create a transient file?

import java.io. *; /** * Work with temporary files in Java. */ public class TempFiles { public static void main(String[] argv) throws IOException { // 1. Make an existing file temporary // Construct a File object for the backup created by editing // this source file.

How do you make a field transient or serializable?

To solve the problem you can:

1. make the field as transient , but it will be ignored during serialization.
2. make the field as private , so SonarQube can verify that nobody assigned non-serializable list to it.
3. change the field type to serializable type (e.g. java. util. ArrayList)

When do you use the transient keyword 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.

How to deserialize an object with a transient variable?

If you deserialize the object, you will get the default value for transient variable. Let’s create a class with transient variable. Now write the code to serialize the object. Now write the code for deserialization. As you can see, printing age of the student returns 0 because value of age was not serialized.

Is there compile time error declaring final variable as transient?

However there is no compilation error. transient and final : final variables are directly serialized by their values, so there is no use/impact of declaring final variable as transient. There is no compile-time error though. This article is contributed by Gaurav Miglani.