EmptyBlock.qhelp

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


<overview>
<p>An unexplained empty block or statement makes the
code less readable. It might also indicate missing code, a
misplaced semicolon, or a misplaced brace. For these reasons, it
should be avoided.</p>

</overview>
<recommendation>

<p>If a block is empty because some code is missing, add the code.</p>
<p>If an <code>if</code> statement has an empty <code>then</code> branch and a non-empty <code>else</code> branch,
it may be possible to negate the condition and move the statements of the <code>else</code> branch into the <code>then</code> branch.</p>
<p>If a block is deliberately empty, add a comment to explain why.</p>

</recommendation>
<example>

<p>In the following example, the <code>while</code> loop has intentionally been left empty.
The purpose of the loop is to scan a <code>String</code> for the first occurrence of
the character <code>'='</code>. A programmer reading the code might not understand the reason
for the empty loop body, and think that something is missing, or perhaps even that the loop is useless.
Therefore it is a good practice to add a comment to an empty block explaining why it is empty.</p>

<sample src="EmptyBlock.java" />

</example>
<references>


<li>
Help - Eclipse Platform:
<a href="http://help.eclipse.org/indigo/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Freference%2Fpreferences%2Fjava%2Fcompiler%2Fref-preferences-errors-warnings.htm">Java Compiler Errors/Warnings Preferences</a>.
</li>
<li>
Java Language Specification:
<a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.2">14.2 Blocks</a>,
<a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.6">14.6 The Empty Statement</a>,
<a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.9">14.9 The if Statement</a>,
<a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.12">14.12 The while Statement</a>,
<a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.13">14.13 The do Statement</a>,
<a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html#jls-14.14">14.14 The for Statement</a>.
</li>


</references>
</qhelp>