Fix NPE when command name is not provided

src/main/java/io/appform/core/hystrix/CommandFactory.java

@@ -30,7 +30,7 @@ public static <R> GenericHystrixCommand<R> create(
 
     public static <R> GenericHystrixCommand<R> create(
             String group, String command) {
-        return create(group,command, UUID.randomUUID().toString().replaceAll("-", ""));
+        return create(group,command, UUID.randomUUID().toString().replace("-", ""));
     }
 
     private CommandFactory() {}

src/main/java/io/appform/core/hystrix/GenericHystrixCommand.java

@@ -59,7 +59,7 @@ protected R run() throws Exception {
                 if (parentMDCContext != null) {
                     MDC.setContextMap(parentMDCContext);
                 }
-                final Span span = TracingHandler.startChildSpan(tracer, parentActiveSpan, command);
+                final Span span = TracingHandler.startChildSpan(tracer, parentActiveSpan, commandKey(group, command));
                 final Scope scope = TracingHandler.activateSpan(tracer, span);
 
                 MDC.put(TRACE_ID, traceId);

src/main/java/io/appform/core/hystrix/TracingHandler.java

@@ -32,14 +32,15 @@ public static Span getParentActiveSpan(final Tracer tracer) {
 
     public static Span startChildSpan(final Tracer tracer,
                                       final Span parentSpan,
-                                      final String command) {
+                                      final String commandKey) {
         try {
             if (tracer == null || parentSpan == null) {
                 return null;
             }
-            return tracer.buildSpan("hystrix:"+command)
+
+            return tracer.buildSpan("hystrix:" + commandKey)
                     .asChildOf(parentSpan)
-                    .withTag("hystrix.command", command)
+                    .withTag("hystrix.command", commandKey)
                     .start();
         } catch (Exception e) {
             log.error("Error while starting child span", e);
@@ -73,4 +74,6 @@ public static void closeScopeAndSpan(final Span span,
             log.error("Error while closing span and scope", e);
         }
     }
+
+    private TracingHandler() {}
 }

src/test/java/io/appform/core/hystrix/CommandFactoryTest.java

@@ -51,4 +51,4 @@ public void testCreateCollectionCommand() {
                 .execute();
         Assert.assertEquals(result, list);
     }
-}
+}