sgammon/GUST

Cognitive Complexity is a measure of how hard the control flow of a method is to understand. Methods with high Cognitive Complexity will be difficult to maintain.

See

• Cognitive Complexity

A dead store happens when a local variable is assigned a value that is not read by any subsequent instruction. Calculating or retrieving a value only to then overwrite it or throw it away, could indicate a serious error in the code. Even if it's not an error, it is at best a waste of resources. Therefore all calculated values should be used.

Noncompliant Code Example

i = a + b; // Noncompliant; calculation result not used before value is overwritten
i = compute();

Compliant Solution

i = a + b;
i += compute();

Exceptions

This rule ignores initializations to -1, 0, 1, null, true, false and "".

See

• MITRE, CWE-563 - Assignment to Variable without Use ('Unused Variable')
• CERT, MSC13-C. - Detect and remove unused values
• CERT, MSC56-J. - Detect and remove superfluous code and values

Even if it is technically possible, Restricted Identifiers should not be used as identifiers. This is only possible for compatibility reasons, using it in Java code is confusing and should be avoided.

Note that this applies to any version of Java, including the one where these identifiers are not yet restricted, to avoid future confusion.

This rule reports an issue when restricted identifiers:

• var
• yield
• record

are used as identifiers.

Noncompliant Code Example

var var = "var"; // Noncompliant: compiles but this code is confusing
var = "what is this?";

int yield(int i) { // Noncompliant
  return switch (i) {
    case 1: yield(0); // This is a yield from switch expression, not a recursive call.
    default: yield(i-1);
  };
}

String record = "record"; // Noncompliant

Compliant Solution

var myVariable = "var";

int minusOne(int i) {
  return switch (i) {
    case 1: yield(0);
    default: yield(i-1);
  };
}

String myRecord = "record";

See

• JLS16, 3.8: Identifiers