<p>Since Checkstyle 3.0</p><p> Checks that a token is surrounded by whitespace. Empty constructor, method, class, enum, interface, loop bodies (blocks), lambdas of the form </p><pre><code>public MyClass() {} // empty constructor public void func() {} // empty method public interface Foo {} // empty interface public class Foo {} // empty class public enum Foo {} // empty enum MyClass c = new MyClass() {}; // empty anonymous class while (i = 1) {} // empty while loop for (int i = 1; i &gt; 1; i++) {} // empty for loop do {} while (i = 1); // empty do-while loop Runnable noop = () -&gt; {}; // empty lambda public @interface Beta {} // empty annotation type </code></pre><p> may optionally be exempted from the policy using the <code> allowEmptyMethods</code>, <code>allowEmptyConstructors </code>, <code>allowEmptyTypes</code>, <code>allowEmptyLoops</code><code>allowEmptyLambdas</code> and <code>allowEmptyCatches</code> properties. </p><p>This check does not flag as violation double brace initialization like:</p><pre><code> new Properties() {{ setProperty("key", "value"); }}; </code></pre><p>Parameter allowEmptyCatches allows to suppress violations when token list contains SLIST to check if beginning of block is surrounded by whitespace and catch block is empty, for example:</p><pre><code> try { k = 5 / i; } catch (ArithmeticException ex) {} </code></pre> With this property turned off, this raises violation because the beginning of the catch block (left curly bracket) is not separated from the end of the catch block (right curly bracket).

<p>Since Checkstyle 3.0</p><p> Checks that a token is surrounded by whitespace. Empty constructor, method, class, enum, interface, loop bodies (blocks), lambdas of the form </p><pre><code>public MyClass() {} // empty constructor public void func() {} // empty method public interface Foo {} // empty interface public class Foo {} // empty class public enum Foo {} // empty enum MyClass c = new MyClass() {}; // empty anonymous class while (i = 1) {} // empty while loop for (int i = 1; i &gt; 1; i++) {} // empty for loop do {} while (i = 1); // empty do-while loop Runnable noop = () -&gt; {}; // empty lambda public @interface Beta {} // empty annotation type </code></pre><p> may optionally be exempted from the policy using the <code> allowEmptyMethods</code>, <code>allowEmptyConstructors </code>, <code>allowEmptyTypes</code>, <code>allowEmptyLoops</code><code>allowEmptyLambdas</code> and <code>allowEmptyCatches</code> properties. </p><p>This check does not flag as violation double brace initialization like:</p><pre><code> new Properties() {{ setProperty("key", "value"); }}; </code></pre><p>Parameter allowEmptyCatches allows to suppress violations when token list contains SLIST to check if beginning of block is surrounded by whitespace and catch block is empty, for example:</p><pre><code> try { k = 5 / i; } catch (ArithmeticException ex) {} </code></pre> With this property turned off, this raises violation because the beginning of the catch block (left curly bracket) is not separated from the end of the catch block (right curly bracket).