IncorrectSerialVersionUID.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
  "qhelp.dtd">
<qhelp>


<overview>
<p>
A serializable class that uses the <code>serialVersionUID</code> field to act as an object version number must declare the field
to be <code>final</code>, <code>static</code>, and of type <code>long</code> for it to be used by the Java serialization framework.
</p>

</overview>
<recommendation>
<p>
Make sure that the <code>serialVersionUID</code> field in a serialized class is final, static, and of type <code>long</code>.
</p>

</recommendation>
<example>

<p>In the following example, <code>WrongNote</code> defines <code>serialVersionUID</code> using the wrong
type, so that it is not used by the Java serialization framework. However, <code>Note</code> defines it correctly
so that it is used by the framework.</p>
 
<sample src="IncorrectSerialVersionUID.java" />

</example>
<references>


<li>
  Java API Specification:
  <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/io/Serializable.html">Serializable</a>.
</li>
<li>
  JavaWorld: <a href="https://www.infoworld.com/article/2071731/ensure-proper-version-control-for-serialized-objects.html">Ensure proper version control for serialized objects</a>.
</li>


</references>
</qhelp>