title: Java 8 constant function naming convention
body: <p>I know about the <a href="http://www.oracle.com/technetwork/java/codeconventions-135099.html" rel="nofollow noreferrer">Oracle Java naming conventions</a> and I've read similar SO questions (like <a href="https://stackoverflow.com/questions/12519475/java-constant-variable-naming-convention">Java constant variable, naming convention</a>) but what naming should I use for constant functions?</p>
  
  <p>E.g. if I have the functional interface</p>
  
  <pre><code>public interface StringDecider {
    public boolean decide(String str);
  }
  </code></pre>
  
  <p>and now I'm using it to define a constant function. Should the naming be 'upper snake case', like</p>
  
  <pre><code>public final static StringDecider STRING_NOT_EMPTY = (str) -&gt; (str!=null &amp;&amp; !str.isEmpty());
  STRING_NOT_EMPTY.decide("Example");
  </code></pre>
  
  <p>or camel case</p>
  
  <pre><code>public final static StringDecider stringNotEmpty = (str) -&gt; (str!=null &amp;&amp; !str.isEmpty());
  stringNotEmpty.decide("Example");
  </code></pre>