Fix NPE when sending DatagramPacket

This is due to code after

  getImpl().connect(address, port);

is not executed if it throws exception, leaving DatagramPacket in an
inconsistant state.

Re-arrange the order of code so that the state is now consistent.

Bug: 31218085
Bug: 31495962

(cherry-picked from commit 6764aa32a4b66a3c589f4a00615a1e36d87f308f)

Test: libcore.java.net.DatagramSocketTest
Change-Id: Iab9bfd9af211666564e49de62fdae964d6330daf

luni/src/test/java/libcore/java/net/DatagramSocketTest.java

@@ -18,8 +18,11 @@
 
 import junit.framework.TestCase;
 
+import java.lang.reflect.Field;
 import java.net.DatagramSocket;
 import java.net.InetSocketAddress;
+import java.net.DatagramSocketImpl;
+import java.net.InetAddress;
 
 public class DatagramSocketTest extends TestCase {
 
@@ -55,4 +58,21 @@ public void testStateAfterClose() throws Exception {
     assertEquals(-1, ds.getLocalPort());
     assertNull(ds.getLocalSocketAddress());
   }
+  // Socket should become connected even if impl.connect() failed and threw exception.
+  public void test_b31218085() throws Exception {
+    final int port = 9999;
+
+    try (DatagramSocket s = new DatagramSocket()) {
+      // Set fd of DatagramSocket to null, forcing impl.connect() to throw.
+      Field f = DatagramSocket.class.getDeclaredField("impl");
+      f.setAccessible(true);
+      DatagramSocketImpl impl = (DatagramSocketImpl) f.get(s);
+      f = DatagramSocketImpl.class.getDeclaredField("fd");
+      f.setAccessible(true);
+      f.set(impl, null);
+
+      s.connect(InetAddress.getLocalHost(), port);
+      assertTrue(s.isConnected());
+    }
+  }
 }

ojluni/src/main/java/java/net/DatagramSocket.java

@@ -162,10 +162,12 @@ private synchronized void connectInternal(InetAddress address, int port) throws
                 // connection will be emulated by DatagramSocket
                 connectState = ST_CONNECTED_NO_IMPL;
           }*/
-          getImpl().connect(address, port);
 
           // socket is now connected by the impl
           connectState = ST_CONNECTED;
+
+          getImpl().connect(address, port);
+
           // ----- END android -----
         }