title: Java 8 stream join and return multiple values
body: <p>I'm porting a piece of code from .NET to Java and stumbled upon a scenario where I want to use stream to map &amp; reduce.</p>
  
  <pre><code>class Content
  {
    private String propA, propB, propC;
    Content(String a, String b, String c)
    {
      propA = a; propB = b; propC = c;
    }
    public String getA() { return propA; }
    public String getB() { return propB; }
    public String getC() { return propC; }
  }
  
  List&lt;Content&gt; contentList = new ArrayList();
  contentList.add(new Content("A1", "B1", "C1"));
  contentList.add(new Content("A2", "B2", "C2"));
  contentList.add(new Content("A3", "B3", "C3"));
  </code></pre>
  
  <p>I want to write a function that can stream through the contents of contentlist and return a class with result</p>
  
  <pre><code>content { propA = "A1, A2, A3", propB = "B1, B2, B3", propC = "C1, C2, C3" }
  </code></pre>
  
  <p>I'm fairly new to Java so you might find some code that resembles more like C# than java</p>