Logical Operators: When Should You Choose `||` Over `|`?

The Benefits of Logical Operators: Why Use || over |?

In programming, we often use logical operators to combine boolean expressions. The two most common logical operators are the logical OR operator (||) and the bitwise OR operator (|). While both operators perform similar functions, there is a key difference that makes || the preferred choice in most scenarios.

The bitwise OR operator (|) performs a bitwise operation, evaluating each bit of the two input booleans and returning the result bit by bit. In contrast, the logical OR operator (||) evaluates the input booleans sequentially, stopping as soon as one of them evaluates to true. This is known as short-circuiting.

Short-circuiting has several advantages over bitwise operation. First, it prevents unnecessary evaluation of the right-hand operand when the left-hand operand is already true. This can improve performance, especially when the right-hand operand is an expensive operation.

For example, consider the following code snippet:

Boolean b = true;
if (b || foo.timeConsumingCall()) {
    // We entered without calling timeConsumingCall()
}

Here, the use of || ensures that the function foo.timeConsumingCall() is not invoked, as the left-hand operand (b) is already true. This can be crucial when dealing with computationally expensive operations.

Another benefit of short-circuiting is null reference checks. If one of the input booleans is a null value, using && to check for falsiness will result in a NullPointerException, whereas || will evaluate to false without causing an error. For example:

String string = null;
if (string != null && string.isEmpty()) {
    // We check for string being null before calling isEmpty()
}

In this case, using && would throw a NullPointerException, while || would correctly evaluate to false.

In summary, while both || and | can be used for logical operations, the use of || is generally preferred due to its short-circuiting behavior. Short-circuiting improves performance and allows for safer null reference checks, making it the more suitable choice for most programming scenarios.

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