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Scope minimization helps to capture in capturing common programming errors, improves code readability by tying together the declaration and actual use of a variable and eases maintainability because unused variables are easily caught and removed.

Noncompliant Code Example

This noncompliant code example shows a variable that is declared outside the for loop. This can harm reusability as the loop index i will change after the for statement. Consider for instance, the case when this code snippet is copy pasted with the intent of using a different index j but the statement mistakenly still iterates over index i. As i is still in scope, this will lead to a unexpected behavior.

public class Scope {
  public static void main(String[] args) {
    int i = 0;
    for(i = 0;i<10; i < 10; i++) {
      //do operations
    }
  }
}

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To be compliant, minimize the scope of variables where possible, such as by declaring loop indexes within the for statement.

public class Scope {
  public static void main(String[] args) {
    for(int i = 0;i<10; i < 10; i++) { //contains declaration
      //do operations
    }
  }
}

...

Using a larger scope than what is necessary results in less reliable code.

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