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The readObject() method must not call any overridable methods. Invoking overridable methods from the readObject() method can cause provide the overriding method with access to read the object's state of the subclass before it is fixedfully initialized. This premature access is because the base class is deserialized first, followed by the subclass. Also see the related guidelines CON09-J. Do not invoke alien methods that rely on invariants protected by the same lock object and MET07possible because, in deserialization, readObject plays the role of object constructor and therefore object initialization is not complete until readObject exits (see also MET06-J. Do not invoke overridable methods on the clone under constructionin clone()).

Noncompliant Code Example

This noncompliant code example invokes an overridable method from the readObject() method. :

private void readObject(final ObjectInputStream stream) throws 

                        throws IOException, ClassNotFoundException {
  overridableMethod(); 
  stream.defaultReadObject();
}

public void overridableMethod() {
  // ...
}

Compliant Solution

This compliant solution removes the call to the overridable method. If this cannot be done, ensure that the overridable method is declared When removing such calls is infeasible, declare the method private or final.

private void readObject(final ObjectInputStream stream) throws 

                        throws IOException, ClassNotFoundException {
  stream.defaultReadObject();
}

Exceptions

SER09-J-EX0: The readObject() method may invoke the overridable methods defaultReadObject() and readFields() in class java.io.ObjectInputStream [SCG 2009].

Risk Assessment

Invoking overridable methods from the readObject() method can lead to initialization errors.

Automated Detection

...

TODO

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

References

Tool	Version	Checker	Description
Parasoft Jtest	Include Page Parasoft_V Parasoft_V	CERT.SER09.VREADOBJ	Do not invoke overridable methods from the readObject() method

Related Guidelines

Bibliography

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\[[API 06|AA. Java References#API 06]\] 
\[[Bloch 08|AA. Java References#Bloch 08]\] Item 17: "Design and document for inheritance or else prohibit it"

SER10-J. Do not serialize direct handles to system resources      14. Serialization (SER)      SER12-J. Avoid memory and resource leaks during serialization