title: Intellij - Unable to use newer Java 8 classes - Error : "Usage of API documented as @since 1.6+.."
body: <p>I'm trying to use a <code>java.lang.function.Function</code> in my java 8 code base, but i keep getting the following error in Intellij.</p>
  
  <blockquote>
    <p>Usage of API documented as @since 1.6+  This inspection finds all
    usages of methods that have @since tag in their documentation.  This
    may be useful when development is performed under newer SDK version as
    the target platform for production</p>
  </blockquote>
  
  <p>I seem to have the correct Project and Compiler settings</p>
  
  <p><strong>Project Settings: (File -> Project Structure)</strong></p>
  
  <pre><code>Project Settings -&gt; Project -&gt; Project SDK = Java 1.8
  Project Settings -&gt; Project -&gt; Project Language Level = 8 - Lambdas, Type Annotations etc
  </code></pre>
  
  <p><strong>Compiler Settings: (File -> Settings)</strong></p>
  
  <pre><code>Build, Execution, Deployment -&gt; Compiler -&gt; Java Compiler -&gt; Project Bytecode Version : 1.8
  Build, Execution, Deployment -&gt; Compiler -&gt; Java Compiler -&gt; Per module Bytecode Version -&gt; Target Bytecode Version : 1.8
  </code></pre>
  
  <p>What is the problem?</p>