473266 - init MultiException cause

jetty-util/src/main/java/org/eclipse/jetty/util/MultiException.java

@@ -47,7 +47,10 @@ public class MultiException extends Exception
             throw new IllegalArgumentException();
         
         if(nested == null)
+        {
+            initCause(e);
             nested = new ArrayList<>();
+        }
         
         if (e instanceof MultiException)
         {

jetty-util/src/test/java/org/eclipse/jetty/util/MultiExceptionTest.java

@@ -148,4 +148,17 @@ public class MultiExceptionTest
             assertTrue(e.getCause()==me);
         }
     }
+    
+    @Test
+    public void testCause() throws Exception
+    {
+        MultiException me = new MultiException();
+        IOException io = new IOException("one");
+        RuntimeException run = new RuntimeException("two");
+        me.add(io);
+        me.add(run);
+
+        assertEquals(2,me.size());
+        assertEquals(io,me.getCause());        
+    }
 }