title: Converting List<String> to String using java streams
body: <p>I have values in an <code>ArrayList</code> as <code>Value1, Value2, Value3</code>.<br />
  Now i need to return them in a way as a Single <code>String</code> as <code>Value1_Value2_Value3</code> using Java <code>Streams</code>.</p>
  <p>I've tried this but it didn't work</p>
  <pre><code>myList.stream().map((s)-&gt;s+&quot;_&quot;).toString();
  </code></pre>
  <p>I've also tried <code>collect(toList());</code> but I'm not sure how to proceed further to convert it to a <code>String</code>.</p>
  <p>How can I do it?</p>