How does Java deal with multiple conditions inside a single IF statement

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Lets say I have this:

if(bool1 && bool2 && bool3) {
...
}

Now. Is Java smart enough to skip checking bool2 and bool2 if bool1 was evaluated to false? Does java even check them from left to right? I'm asking this because i was "sorting" the conditions inside my if's by the time it takes to do them (starting with the cheapest ones on the left). Now I'm not sure if this gives me any performance benefits because i don't know how Java handles this.

Yes, Java (similar to other mainstream languages) uses lazy evaluation short-circuiting which means it evaluates as little as possible.

This means that the following code is completely safe:

if(p != null && p.getAge() > 10)

Also, a || b never evaluates b if a evaluates to true.

How does Java deal with multiple conditions inside a single IF , Yes, Java (similar to other mainstream languages) uses lazy evaluation short- circuiting which means it evaluates as little as possible. How does Java deal with multiple conditions inside a single IF statement. Ask Question Asked 8 years, Multiple conditions in one if statement in JAVA. 1.

Is Java smart enough to skip checking bool2 and bool2 if bool1 was evaluated to false?

Its not a matter of being smart, its a requirement specified in the language. Otherwise you couldn't write expressions like.

if(s != null && s.length() > 0)

or

if(s == null || s.length() == 0)

BTW if you use & and | it will always evaluate both sides of the expression.

Best way to format if statement with multiple conditions, If you do have particularly long variables/method conditions you can just line if ( ( single conditional expression A ) && ( single conditional Formatting a multiple conditional expressions in an if-else statement this way:. When you write multiple if statements, it's possible that more than one of them will be evaluated to true, since the statements are independent of each other. When you write a single if else-if else-if else statement, only one condition can be evaluated to true (once the first condition that evaluates to true is found, the next else-if conditions are skipped).

Please look up the difference between & and && in Java (the same applies to | and ||).

& and | are just logical operators, while && and || are conditional logical operators, which in your example means that

if(bool1 && bool2 && bool3) {

will skip bool2 and bool3 if bool1 is false, and

if(bool1 & bool2 & bool3) {

will evaluate all conditions regardless of their values.

For example, given:

boolean foo() {
    System.out.println("foo");
    return true;
}

if(foo() | foo()) will print foo twice, and if(foo() || foo()) - just once.

Approaches to checking multiple conditions?, Does any one of A, B, C, or D cause it not to work? _2)) else None If we only need the first error, in Java I'd do fail-fast while in Scala I might Your condition in the while loop is: ((continueSurvey != 0) && (i < 3)) which means that the inner block of the while loop will be executed if and only if continuSurvey != 0 and i < 3 in the same time. You have inner loops which have different conditions. I would search for the problem in the inner loops using a debugger.

Yes,that is called short-circuiting.

Please take a look at this wikipedia page on short-circuiting

java for complete beginners - if else, more about using if statements in java. Anything not caught by the first two conditions will be caught be the final else. Again, code is sectioned off using curly � a specific condition exists. It is said that the statements inside of the decision structure are… conditionally executed. Relational Operators determine whether… a specific relationship exist between two values. Some relational operators in Java are… > , < , >= , <= , == , != General for of an if statement:

How many conditions can be used inside an if statement , Can I use nested if statements to solve this or will that not work either? -does- java-deal-with-multiple-conditions-inside-a-single-if-statement. For Loop with Multiple Conditions The for loop has several capabilities that are not found in other loop constructs. For example, more than one variable can be initialized at a time in the for statement using comma. The test condition may have any compound relation.

If, If..else Statement in Java with Examples, In this case we have two print statements in the program, but only one print statement If the condition is false then the statements inside if statement body are� If the single statement looks good on a single line after the if clause, I don't use braces. For any other if statement (or any statement that uses multiple lines), I always use braces. In particular, if there's an else clause, each case always has braces. – eswald Nov 3 '10 at 17:33. 9.

Combining conditions: logical operators, To check for one condition or the other, we use two pipe symbols. We can use the Java else statement to add some code to be executed when a given On the next page, we look at arrays in Java, which allow us to deal with a "row of� If we intend to apply only 'if' logic then we can pass the condition directly do the filter() function. In given example, we are checking if a number id even then print a message. ArrayList<Integer> numberList = new ArrayList<>(Arrays.asList(1,2,3,4,5,6)); numberList.stream() .filter(i -> i % 2 == 0) .forEach(System.out::println);

Comments
  • Since you're trying to improve performance with these changes, have you tried measuring the performance before and after moving the conditions? On one hand, that should tell you whether the logic is indeed being short-circuited as explained below, and on the other, it will tell you if the magnitude of these changes are significant in the bigger picture.
  • sorry for digging up an old thread, but why do you have " && and " ? do you mean just " && " ?