LowFile-scopeJava Plug & play

Avoid Redundant Null Checks with `instanceof`

Ensure that explicit null checks are not used with `instanceof`, as `null` is never an instance of any class.

Why this matters

`null` is never an instance of any class, making explicit null checks redundant when using `instanceof`. This check should be removed.

Side-by-side examples engineers can pattern-match during review.

Avoid

if (x != null && x instanceof MyClass) { ... }  // Noncompliant

if (x == null || ! x instanceof MyClass) { ... } // Noncompliant

Prefer

if (x instanceof MyClass) { ... }

if (! x instanceof MyClass) { ... }

Bad

if (x != null && x instanceof MyClass) { ... }  // Noncompliant

if (x == null || ! x instanceof MyClass) { ... } // Noncompliant

Good

if (x instanceof MyClass) { ... }

if (! x instanceof MyClass) { ... }

From the same buckets as this rule.

Critical
Avoid Duplicating String Literals
Store repeated string literals in constants or variables to improve maintainability and reduce redundancy.
duplication-complexitymaintainability
Critical
Avoid Redundant `None` Comparisons
Identify cases where `x is None` or `x is not None` is used redundantly when `x` is always or never `None`. This may indicate a deeper logic issue.
duplication-complexityreadability-refactor+1
High
Avoid Functions That Always Return the Same Value
Identify functions that return the same value regardless of input. This may indicate poor design or a logic error.
duplication-complexityreadability-refactor+1