diff --git a/ugs-core/src/com/willwinder/universalgcodesender/AbstractController.java b/ugs-core/src/com/willwinder/universalgcodesender/AbstractController.java
index 7b3af67a5..7291f6259 100644
--- a/ugs-core/src/com/willwinder/universalgcodesender/AbstractController.java
+++ b/ugs-core/src/com/willwinder/universalgcodesender/AbstractController.java
@@ -41,6 +41,8 @@ This file is part of Universal Gcode Sender (UGS).
 import java.util.Optional;
 import java.util.concurrent.BlockingDeque;
 import java.util.concurrent.LinkedBlockingDeque;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -65,17 +67,17 @@ public abstract class AbstractController implements ICommunicatorListener, ICont
     protected MessageService messageService;
 
     // Added value
-    private Boolean isStreaming = false;
+    private final AtomicBoolean isStreaming = new AtomicBoolean(false);
 
     // For keeping track of the time spent streaming a file
     private final StopWatch streamStopWatch = new StopWatch();
 
     // This metadata needs to be cached instead of looked up from queues and
     // streams, because those sources may be compromised during a cancel.
-    private int numCommands = 0;
-    private int numCommandsSent = 0;
-    private int numCommandsSkipped = 0;
-    private int numCommandsCompleted = 0;
+    private final AtomicInteger numCommands = new AtomicInteger(0);
+    private final AtomicInteger numCommandsSent =  new AtomicInteger(0);
+    private final AtomicInteger numCommandsSkipped = new AtomicInteger(0);
+    private final AtomicInteger numCommandsCompleted = new AtomicInteger(0);
 
     // Commands become active after the Communicator notifies us that they have
     // been sent.
@@ -387,7 +389,7 @@ public Boolean isCommOpen() {
 
     @Override
     public Boolean isStreaming() {
-        return this.isStreaming;
+        return isStreaming.get();
     }
 
     /**
@@ -416,13 +418,13 @@ private enum RowStat {
     public int getRowStat(RowStat stat) {
         switch (stat) {
             case TOTAL_ROWS:
-                return this.numCommands;
+                return numCommands.get();
             case ROWS_SENT:
-                return this.numCommandsSent;
+                return numCommandsSent.get();
             case ROWS_COMPLETED:
-                return this.numCommandsCompleted + this.numCommandsSkipped;
+                return numCommandsCompleted.get() + numCommandsSkipped.get();
             case ROWS_REMAINING:
-                return this.numCommands <= 0 ? 0 : this.numCommands - (this.numCommandsCompleted + this.numCommandsSkipped);
+                return numCommands.get() <= 0 ? 0 : numCommands.get() - (numCommandsCompleted.get() + numCommandsSkipped.get());
             default:
                 throw new IllegalStateException("This should be impossible - RowStat default case.");
         }
@@ -527,13 +529,13 @@ public void beginStreaming() throws Exception {
             throw new Exception("There are no commands queued for streaming.");
         }
 
-        this.isStreaming = true;
-        this.streamStopWatch.reset();
-        this.streamStopWatch.start();
-        this.numCommands = 0;
-        this.numCommandsSent = 0;
-        this.numCommandsSkipped = 0;
-        this.numCommandsCompleted = 0;
+        isStreaming.set(true);
+        streamStopWatch.reset();
+        streamStopWatch.start();
+        numCommands.set(0);
+        numCommandsSent.set(0);
+        numCommandsSkipped.set(0);
+        numCommandsCompleted.set(0);
         updateNumCommands();
 
         // Send all queued commands and streams then kick off the stream.
@@ -545,7 +547,7 @@ public void beginStreaming() throws Exception {
 
             comm.streamCommands();
         } catch(Exception e) {
-            this.isStreaming = false;
+            isStreaming.set(false);
             this.streamStopWatch.reset();
             this.comm.cancelSend();
             throw e;
@@ -614,9 +616,11 @@ public void cancelJog() throws Exception {
 
     @Override
     public void cancelCommands() {
-        this.comm.cancelSend();
-        this.isStreaming = false;
-        if (this.streamStopWatch.isStarted()) this.streamStopWatch.stop();
+        comm.cancelSend();
+        isStreaming.set(false);
+        if (streamStopWatch.isStarted()) {
+            streamStopWatch.stop();
+        }
     }
 
     @Override
@@ -628,35 +632,33 @@ public void resetBuffers() {
 
     // Reset send queue and idx's.
     private void flushSendQueues() {
-        numCommands = 0;
+        numCommands.set(0);
     }
 
     private void updateNumCommands() {
         if (streamCommands != null) {
-            numCommands = streamCommands.getNumRows();
+            numCommands.set(streamCommands.getNumRows());
         }
-        numCommandsSkipped = 0;
-        numCommandsCompleted = 0;
-        numCommandsSent = 0;
+        numCommandsSkipped.set(0);
+        numCommandsCompleted.set(0);
+        numCommandsSent.set(0);
     }
 
     // No longer a listener event
     protected void fileStreamComplete(String filename) {
-
-        String duration =
-                com.willwinder.universalgcodesender.Utils.
-                        formattedMillis(this.getSendDuration());
-
-        this.dispatchConsoleMessage(MessageType.INFO,"\n**** Finished sending file in "+duration+" ****\n\n");
-        this.streamStopWatch.stop();
-        this.isStreaming = false;
+        String duration = Utils.formattedMillis(getSendDuration());
+        dispatchConsoleMessage(MessageType.INFO, String.format("%n**** Finished sending file in %s ****%n%n", duration));
+        if (streamStopWatch.isStarted()) {
+            streamStopWatch.stop();
+        }
+        isStreaming.set(false);
         dispatchStreamComplete(filename);
     }
 
     @Override
     public void commandSent(GcodeCommand command) {
         if (this.isStreaming()) {
-            this.numCommandsSent++;
+            numCommandsSent.incrementAndGet();
         }
 
         command.setSent(true);
@@ -697,7 +699,7 @@ public void checkStreamFinished() {
     @Override
     public void commandSkipped(GcodeCommand command) {
         if (this.isStreaming()) {
-            this.numCommandsSkipped++;
+            numCommandsSkipped.incrementAndGet();
         }
 
         StringBuilder message = new StringBuilder();
@@ -753,7 +755,7 @@ public void commandComplete(String response) throws UnexpectedCommand {
         updateCommandFromResponse(command, response);
         updateParserModalState(command);
 
-        numCommandsCompleted++;
+        numCommandsCompleted.incrementAndGet();
 
         if (activeCommands.isEmpty()) {
             setCurrentState(COMM_IDLE);