java_gen: add optional instrumentation
diff --git a/java_gen/templates/_imports.java b/java_gen/templates/_imports.java
index 55e9a2d..2187bab 100644
--- a/java_gen/templates/_imports.java
+++ b/java_gen/templates/_imports.java
@@ -14,6 +14,8 @@
 import org.projectfloodlight.openflow.types.*;
 import org.projectfloodlight.openflow.util.*;
 import org.projectfloodlight.openflow.exceptions.*;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.jboss.netty.buffer.ChannelBuffers;
 import com.google.common.collect.ImmutableList;