title: Eclipse 2021-06: ClassFormatError accessible: module java.base does not "opens java.lang" to unnamed module
body: <p>Upgrading to the last Eclipse version, now I am getting the following error:</p>
  <pre><code>Unable to make protected final java.lang.Class java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int) throws java.lang.ClassFormatError accessible: module java.base does not &quot;opens java.lang&quot; to unnamed module @5d01b0d8
  </code></pre>
  <p>I tried changing JDK under preferences with no luck.</p>