title: java conversion: MultivalueMap<String,String> to Map<String,String[]>
body: <p>I'm working with Java and Spring.</p>
  
  <p>I'm obtaining a <code>MultiValueMap&lt;String,String&gt;</code>. This is helpful to me because I can store more than one value for a each <code>key</code>. But a library I'm using requires a type of <code>Map&lt;String,String[]&gt;</code> instead. More particularly I am working with a <code>ParameterMap</code>. How do I perform such conversion?</p>