4e0e265d9e
They redirect to https://wiki.sei.cmu.edu. Fix broken links for open rules. Remove broken links from closed rules. Remove links in Java rules for CERT C rules with no obvious replacement. Expand broken tinyurl to CERT.
57 lines
1.7 KiB
Plaintext
57 lines
1.7 KiB
Plaintext
== Why is this an issue?
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Referencing a static member of a subclass from its parent during class initialization, makes the code more fragile and prone to future bugs.
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The execution of the program will rely heavily on the order of initialization of classes and their static members.
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=== What is the potential impact?
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This could create what is known as an "initialization cycle", or even a deadlock in some extreme cases.
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Additionally, if the order of the static class members is changed, the behavior of the program might change.
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These issues can be very hard to diagnose so it is highly recommended to avoid creating this kind of dependencies.
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=== Noncompliant code example
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[source,java]
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----
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class Parent {
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static int field1 = Child.method(); // Noncompliant
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static int field2 = 42;
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public static void main(String[] args) {
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System.out.println(Parent.field1); // will display "0" instead of "42"
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}
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}
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class Child extends Parent {
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static int method() {
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return Parent.field2;
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}
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}
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----
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== Resources
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* CERT - https://wiki.sei.cmu.edu/confluence/display/java/DCL00-J.+Prevent+class+initialization+cycles[DCL00-J. Prevent class initialization cycles]
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* https://docs.oracle.com/javase/specs/jls/se17/html/jls-12.html#jls-12.4[Section 12.4: Initialization of Classes and Interfaces] - Java Language Specification
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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Remove this reference to "xxx".
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== Comments And Links
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(visible only on this page)
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=== on 07 Jun 2023, 15:18:13 Leonardo Pilastri wrote:
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The rule is very limited and is mentioning the parent-child class relationship, which is actually not the root cause.
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Should be reworked.
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endif::env-github,rspecator-view[]
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