Update AbstractCommandExecutor.java

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/AbstractCommandExecutor.java

@@ -349,15 +349,15 @@ public abstract class AbstractCommandExecutor {
                     long lastFlushTime = System.currentTimeMillis();
 
                     while ((line = inReader.readLine()) != null || logBuffer.size() > 0) {
-                        if (line.startsWith("${setValue(")) {
-                            varPool.append(line.substring("${setValue(".length(), line.length() - 2));
-                            varPool.append("$VarPool$");
-                        } else {
-                            if (null != line) {
-                            logBuffer.add(line);
-                            }
-                            lastFlushTime = flush(lastFlushTime);
-                        }
+                        if (null != line) {
+                           if (line.startsWith("${setValue(")) {
+                              varPool.append(line.substring("${setValue(".length(), line.length() - 2));
+                              varPool.append("$VarPool$");
+                            } else {
+                              logBuffer.add(line);
+                              }
+                           }
+                         lastFlushTime = flush(lastFlushTime);
                     }
                 } catch (Exception e) {
                     logger.error(e.getMessage(), e);