title: Get an array of Strings matching a pattern from a String
body: <p>I have a long string let's say</p>
  
  <pre><code>I like this #computer and I want to buy it from #XXXMall.
  </code></pre>
  
  <p>I know the regular expression pattern is </p>
  
  <pre><code>Pattern tagMatcher = Pattern.compile("[#]+[A-Za-z0-9-_]+\\b");
  </code></pre>
  
  <p>Now i want to get all the hashtags in an array. How can i use this expression to get array of all hash tags from string something like </p>
  
  <pre><code>ArrayList hashtags = getArray(pattern, str)
  </code></pre>