[WIP] Upgrade ONOS to karaf version 4.2.1

Change-Id: I7cd40c995bdf1c80f94b1895fb3344e32404c7fa
diff --git a/web/gui/src/main/java/org/onosproject/ui/impl/topo/cli/UiCacheHostsCommand.java b/web/gui/src/main/java/org/onosproject/ui/impl/topo/cli/UiCacheHostsCommand.java
index f2ec711..99a0360 100644
--- a/web/gui/src/main/java/org/onosproject/ui/impl/topo/cli/UiCacheHostsCommand.java
+++ b/web/gui/src/main/java/org/onosproject/ui/impl/topo/cli/UiCacheHostsCommand.java
@@ -16,7 +16,7 @@
 
 package org.onosproject.ui.impl.topo.cli;
 
-import org.apache.karaf.shell.commands.Command;
+import org.apache.karaf.shell.api.action.Command;
 import org.onosproject.ui.impl.topo.model.UiSharedTopologyModel;
 
 /**
@@ -27,7 +27,7 @@
 public class UiCacheHostsCommand extends AbstractUiCacheElementCommand {
 
     @Override
-    protected void execute() {
+    protected void doExecute() {
         UiSharedTopologyModel model = get(UiSharedTopologyModel.class);
         sorted(model.getHosts()).forEach(h -> print("%s", h));
     }