Update server/src/main/java/com/cloud/api/ApiResponseHelper.java

Co-authored-by: Pearl Dsilva <pearl1594@gmail.com>

Author: PrashantBhanage

server/src/main/java/com/cloud/api/ApiResponseHelper.java

@@ -4347,7 +4347,9 @@ private UsageResourceDetails populateNetworkBytesUsageResponse(Usage usageRecord
                 if (network.getUuid() != null){
                     builder.append(" (").append(network.getUuid()).append(") ");
                 }
-                builder.append(" " + toHumanReadableSize(usageRecord.getRawUsage().longValue())  + " ");
+                if (usageRecord.getRawUsage()!= null) {
+                    builder.append(" " + toHumanReadableSize(usageRecord.getRawUsage().longValue())  + " ");
+                }
             }
             if (vm != null) {
                 builder.append("using router ").append(vm.getInstanceName()).append(" (").append(vm.getUuid()).append(")");