Make public fields final where possible

Class fields initialized via the constructor should be final.

Also mark leaking byte[] instances with a FIXME. API users consider them
immutable, but they are vulnerable to System.arrayCopy().

Also fixes constructor arguments so they do not use underscores, which
is prohibited by Java 9.

Change-Id: I393d55ed7234149cb3604bc92b2cb1d1207c55dc
Signed-off-by: Robert Varga <nite@hq.sk>
diff --git a/vpp-japi/japi/org/openvpp/vppjapi/vppInterfaceCounters.java b/vpp-japi/japi/org/openvpp/vppjapi/vppInterfaceCounters.java
index 1777d5d..8a02ad0 100644
--- a/vpp-japi/japi/org/openvpp/vppjapi/vppInterfaceCounters.java
+++ b/vpp-japi/japi/org/openvpp/vppjapi/vppInterfaceCounters.java
@@ -17,29 +17,29 @@
 
 public class vppInterfaceCounters {
 
-    public long rxOctets;
-    public long rxIp4;
-    public long rxIp6;
-    public long rxUnicast;
-    public long rxMulticast;
-    public long rxBroadcast;
-    public long rxDiscard;
-    public long rxFifoFull;
-    public long rxError;
-    public long rxUnknownProto;
-    public long rxMiss;
+    public final long rxOctets;
+    public final long rxIp4;
+    public final long rxIp6;
+    public final long rxUnicast;
+    public final long rxMulticast;
+    public final long rxBroadcast;
+    public final long rxDiscard;
+    public final long rxFifoFull;
+    public final long rxError;
+    public final long rxUnknownProto;
+    public final long rxMiss;
 
-    public long txOctets;
-    public long txIp4;
-    public long txIp6;
-    public long txUnicast;
-    public long txMulticast;
-    public long txBroadcast;
-    public long txDiscard;
-    public long txFifoFull;
-    public long txError;
-    public long txUnknownProto;
-    public long txMiss;
+    public final long txOctets;
+    public final long txIp4;
+    public final long txIp6;
+    public final long txUnicast;
+    public final long txMulticast;
+    public final long txBroadcast;
+    public final long txDiscard;
+    public final long txFifoFull;
+    public final long txError;
+    public final long txUnknownProto;
+    public final long txMiss;
 
     public vppInterfaceCounters(
             long rxOctets, long rxIp4, long rxIp6, long rxUni, long rxMulti,