title: References to interface static methods are allowed only at source level 1.8 or above
body: <p>What do I need in order to solve this problem?
  How to change JRE Library in Eclipse Project?</p>
  <pre><code>import java.util.Set;
  import java.util.SortedSet;
  import java.util.TreeSet;
  import java.util.stream.Stream;
  import java.util.stream.Collectors;
  
  public class LabelGroup {
  SortedSet&lt;String&gt; strSet1 = Stream.of(&quot;A&quot;, &quot;B&quot;, &quot;C&quot;, &quot;D&quot;)
               .collect(Collectors.toUnmodifiableSet());
      
  }
  </code></pre>
  <p>Eclipse shows at Stream.of:</p>
  <p>References to interface static methods are allowed only at source level 1.8 or above</p>
  <p>Tried to install new software from <a href="http://download.eclipse.org/eclipse/updates/4.3-P-builds/" rel="nofollow noreferrer">official site</a> as suggested <a href="https://wiki.eclipse.org/JDT/Eclipse_Java_8_Support_For_Kepler" rel="nofollow noreferrer">by wiki</a>.</p>
  <p>Response:</p>
  <blockquote>
  <p>Could not find (the software).</p>
  <p>About Eclipse: Eclipse IDE for Enterprise Java Developers Version:
  2018-12 (4.10.0) Build id: 20181214-0600</p>
  <p>Project Settings: java build path: JRE System Library [JavaSE - 1.7]</p>
  </blockquote>