Is There a Difference in Removing the Curly Braces from If Statements in Java

Is there a difference in removing the curly braces from If statements in java

For a single statement it will remain same, but if you want to group more than one statement in the if block then you have to use curly braces.

if("pie"== "pie"){
    System.out.println("Hurrah!");
    System.out.println("Hurrah!2");
}

if("pie"== "pie")
    System.out.println("Hurrah!"); //without braces only this statement will fall under if
    System.out.println("Hurrah!2"); //not this one

You should see: Blocks in Java

A block is a group of zero or more statements between balanced braces
and can be used anywhere a single statement is allowed. The following
example, BlockDemo, illustrates the use of blocks:

class BlockDemo {
     public static void main(String[] args) {
          boolean condition = true;
          if (condition) { // begin block 1
               System.out.println("Condition is true.");
          } // end block one
          else { // begin block 2
               System.out.println("Condition is false.");
          } // end block 2
     }
}

(example from the above link)

Is it ok if I omit curly braces in Java?

It won't change anything at all apart from the maintainability of your code. I've seen code like this:

for (int i = 0; i < size; i++)
   a += b;
   System.out.println("foo");

which means this:

for (int i = 0; i < size; i++)
   a += b;
System.out.println("foo");

... but which should have been this:

for (int i = 0; i < size; i++) {
   a += b;
   System.out.println("foo");
}

Personally I always include the brackets to reduce the possibility of confusion when reading or modifying the code.

The coding conventions at every company I've worked for have required this - which is not to say that some other companies don't have different conventions...

And just in case you think it would never make a difference: I had to fix a bug once which was pretty much equivalent to the code above. It was remarkably hard to spot... (admittedly this was years ago, before I'd started unit testing, which would no doubt have made it easier to diagnose).

Is it a bad practice to use an if-statement without curly braces?

The problem with the first version is that if you go back and add a second statement to the if or else clauses without remembering to add the curly braces, your code will break in unexpected and amusing ways.

Maintainability-wise, it's always smarter to use the second form.

EDIT: Ned points this out in the comments, but it's worth linking to here, too, I think. This is not just some ivory-tower hypothetical bullshit: https://www.imperialviolet.org/2014/02/22/applebug.html

If-Else Control Flow without curly braces

Indent correctly to see

if(1==2)
    System.out.println(x);
if(x!=10)
    System.out.println("X is equal to "+x);
else
    System.out.println("X is not equal to 10!");

I think that answers it already.

But more detailed:

First if is not true, the first println does not get executed (apart from the described second version).

Second if is unconditionally evaluated, is not true, the else is executed.

Or ot reflect it on the quote, there is no "inner" if because there is no if enclosing any other if.

Or another aspect, you seem to think that the output is occurring because the first ifs condition is false, i.e. the else is attached to the first if. It is however attached to the second if because the conditional code influenced by the first if ends at the ;. To have more code influenced by the first if you could introduce a block of several lines, with a pair of {}.

compiler behavior on curly braces and semicolon if statement

I do not understand why answer E is allowed and compiles.

In Java, a ; can either be a statement terminator or an empty statement, depending on the context.

Here's is how the (valid) Java code in option E is parsed:

  if (true) // <-- "if" and its condition
  ;         // an empty statement which is the "then" part of the "if"
  {}        // an (empty) block statement
  ;         // an empty statement

The first two lines are the complete if statement. The third and fourth lines are statements following the if statement.

Why an IF block is allowed inside another IF that doesn't have curly brackets in JAVA

Normally in JAVA if an IF statement doesn't have curly brackets can have only one line that is executed when IF condition is met,

Correction. An if statement without braces can have only one statement that is executed when the condition is met. And the syntax of if goes something like

if (<condition>) <statement>; [else <statement>;]

That is, if there's an else, it's part of the if. It's all one statement.

The reason there's no error is because there's no ambiguity here. (Well, not to the compiler, anyway.) Since the else is part of the if, it goes with the closest if. So with proper indenting, you have

if (true)
    if (true)
       System.out.println("true");
    else
       System.out.println("false");

Curly braces in if-else blocks

For example:

if (something)
      if (something else)
      ...
      else (blah blah)

Is the same that:

 if (something)
   {
      if (something else)
      ...
      else (blah blah)
   }

In this case, yes, they're the same, but the former is harder to read than the latter. I recommend using braces always, even for blocks of code made of a single line.

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