UseBraces.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
  "qhelp.dtd">
<qhelp>


<overview>
<p>A control structure (an <code>if</code> statement or a loop) has a body that is either a block
of statements surrounded by curly braces or a single statement.</p>

<p>If you omit braces, it is particularly important to ensure that the indentation of the code
matches the control flow of the code.</p>

</overview>
<recommendation>

<p>It is usually considered good practice to include braces for all control
structures in Java. This is because it makes it easier to maintain the code
later. For example, it's easy to see at a glance which part of the code is in the
scope of an <code>if</code> statement, and adding more statements to the body of the <code>if</code>
statement is less error-prone.</p>

<p>You should also ensure that the indentation of the code is consistent with the actual flow of 
control, so that it does not confuse programmers.</p>

</recommendation>
<example>

<p>In the example below, the original version of <code>Cart</code> is missing braces. This means 
that the code triggers a <code>NullPointerException</code> at runtime if <code>i</code>
is <code>null</code>.</p>

<sample src="UseBraces.java" />

<p>The corrected version of <code>Cart</code> does include braces, so
that the code executes as the indentation suggests.</p>

<sample src="UseBracesGood.java" />

<p>
In the following example the indentation may or may not be misleading depending on your tab width
settings. As such, mixing tabs and spaces in this way is not recommended, since what looks fine in
one context can be very misleading in another.
</p>

<sample src="UseBraces2.java" />

<p>
If you mix tabs and spaces in this way, then you might get seemingly false positives, since your
tab width settings cannot be taken into account.
</p>

</example>
<references>


<li>
  Java SE Documentation:
  <a href="https://www.oracle.com/java/technologies/javase/codeconventions-statements.html#15395">Compound Statements</a>.
</li>
<li>
  Wikipedia:
  <a href="https://en.wikipedia.org/wiki/Indentation_style">Indentation style</a>.
</li>


</references>
</qhelp>