title: What is the difference between jre folder under JDK folder and jre folder?
body: <ul>
  <li>NOTE: <strong>The question is not about the difference between JDK and JRE.</strong></li>
  </ul>
  
  <p>Oh, I am sorry. <strong>The question is not discuss about JDK and JRE.</strong> But I cannot express clearly in my title. So I try to explain in here. </p>
  
  <p>I want to know the difference between two folders! </p>
  
  <p><code>C:\Program Files\Java\jdk1.8.0_161\jre</code> and <code>C:\Program Files\Java\jre1.8.0_161</code></p>
  
  <h2>Describe in details:</h2>
  
  <p>I am new to JAVA. I have installed the JDK in my Windows 10.  When I install jdk, there were two steps. After double click <code>jdk-8u161-windows-x64.exe</code>, two steps as follows:</p>
  
  <ol>
  <li><p>Step 1: install jdk.  (In <code>C:\Program Files\Java\jdk1.8.0_161</code>)</p></li>
  <li><p>Step 2: install jre.  (In <code>C:\Program Files\Java\jre1.8.0_161</code>)</p></li>
  </ol>
  
  <p>But when I open the <code>jdk1.8.0_161</code> folder. I can also find a <code>jre</code> folder.</p>
  
  <p>Could anyone tell me the difference between <code>C:\Program Files\Java\jdk1.8.0_161\jre</code> and <code>C:\Program Files\Java\jre1.8.0_161</code>?</p>
  
  <p>If they are the same, why is <code>jre</code> installed in the installation process of <code>jdk</code> ?  Are they duplicated?<br>
  In other world, is Step 2 needless?</p>