SerializationException on junit test

Question

I have the following classes:

import lombok.Data;

import java.io.Serializable;

@Data
public class Person implements Serializable {
    private String age;
}

Main Application

import org.apache.commons.lang3.SerializationUtils;

public class MainApp {
    public static void main(String[] args) {
        Person v = new Person() {{
            setAge("SD");
        }};
        Person person2 = SerializationUtils.clone(v);
    }
}

Test Class

import org.apache.commons.lang3.SerializationUtils;
import org.junit.Test;

public class TestClass {
    @Test
    public void test() {
        Person v = new Person() {{
            setAge("SD");
        }};
        Person person2 = SerializationUtils.clone(v);
    }
}

In the main application the serialization works and in the unit test it doesn't. It throws SerializationException with the following details: org.apache.commons.lang3.SerializationException: java.io.NotSerializableException: com.mypackage.TestClass

I'm using intellij and the project is maven project and the tests are JUnit4. dependency version:

  <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.3.2</version>
  </dependency>

Please advise how can I solve it?

Andy Turner · Accepted Answer · 2018-10-23T07:20:14.150

2

You are declaring an anonymous class in the test.

Anonymous classes in non-static scopes (in an instance method, constructor, instance initializer, or instance member initializer) implicitly enclose a reference to the enclosing class (in this case, TestClass).

As that class isn't serializable, it can't be serialized.

Declare your anonymous subclass as a static class instead.

public class TestClass {
    @Test
    public void test() {
        Person v = new TestPerson();
        Person person2 = SerializationUtils.clone(v);
    }

  static class TestPerson extends Person {
    {
      setAge("SD");
    }
  }
}

Or, better, don't use double-brace initialization, especially if you don't understand the problems it causes with respect to serialization (as well as other problems):

Person v = new Person();
v.setAge("SD");
Person person2 = SerializationUtils.clone(v);

edited Oct 23 '18 at 07:20

answered Oct 23 '18 at 07:15

Andy Turner

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What is the anonymous class i declared in the test? – Daniel Grin Oct 23 '18 at 07:16
@DanielGrin "`new Person() {{ ... }}`". – Andy Turner Oct 23 '18 at 07:18
Can you please add an example for both ways? – Daniel Grin Oct 23 '18 at 07:18
@DanielGrin "both ways"? – Andy Turner Oct 23 '18 at 07:21
Thanks alot it solved my problem but still one question. im using the same anonymous class in the MainApp why is it working there? – Daniel Grin Oct 23 '18 at 07:35
@DanielGrin because either you are declaring it in a static scope, or in instance scope in a class which implements `Serializable`. – Andy Turner Oct 23 '18 at 07:37
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/182328/discussion-between-daniel-grin-and-andy-turner). – Daniel Grin Oct 23 '18 at 07:41

SerializationException on junit test

1 Answers1