Dereferenced expression may be null¶
ID: java/dereferenced-expr-may-be-null
Kind: problem
Severity: warning
Precision: high
Tags:
- reliability
- correctness
- exceptions
- external/cwe/cwe-476
Query suites:
- java-security-and-quality.qls
Click to see the query in the CodeQL repository
Dereferencing a null value leads to a NullPointerException.
An expression may be implicitly dereferenced if its type is a boxed primitive type, and it occurs in a context in which implicit unboxing occurs.
Recommendation¶
Ensure that the expression does not have a null value when it is dereferenced. Use boxed types as appropriate to hold values that are potentially null.
Example¶
In the following example implicit unboxing can cause a NullPointerException if helper is null.
public int getID() {
return helper == null ? null : helper.getID();
}
If the method is intended to return null, the return type should be changed to Integer.
References¶
- The Java Tutorials: Autoboxing and Unboxing.
- Common Weakness Enumeration: CWE-476.