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Control Structures Should Use Curly Braces

High
maintainabilityreliability

What is it?​

This practice is triggered when control structures such as if, for, or while statements in Java do not use curly braces for their body.

Why apply it?​

Omitting curly braces can lead to code that is misleading and error-prone during maintenance. Using curly braces improves readability and ensures that control structures only affect the intended statements.

How to fix it?​

Always include curly braces with control structures to clearly define the code block they affect.

Examples​

Example 1:​

Negative​

The negative example omits curly braces, which can lead to confusion about which statements are inside the control structure.

for (int i = 0; i < 5; i++)
    if (i % 2 == 0)
        System.out.println("Even number: " + i);
    continueProcessing(); // This will always be executed.

Example 2:​

Positive​

The positive example uses curly braces for the if statement and for loop, ensuring clear block definitions.

for (int i = 0; i < 5; i++) {
    if (i % 2 == 0) {
        System.out.println("Even number: " + i);
        continueProcessing();
    }
}

Negative​

The negative example omits curly braces for the while loop, making it appear as if multiple statements are part of the loop body, when only the first one is.

int i = 0;
while (i < 5)
    if (checkCondition(i))
        performAction(i);
    i++;  // This will run independently of the condition.

Example 3:​

Positive​

The positive example uses curly braces with the while loop, clearly defining the statements within the loop body.

int i = 0;
while (i < 5) {
    if (checkCondition(i)) {
        performAction(i);
        i++;
    }
}