specific exception

src/main/java/de/hottis/mbusMaster/MbusMaster.java

@@ -1,5 +1,7 @@
 package de.hottis.mbusMaster;
 
+import java.io.IOException;
+
 import java.util.Properties;
 
 import org.apache.logging.log4j.LogManager;
@@ -26,13 +28,17 @@ public class MbusMaster {
 		mbusgw.start();
 
 
-		mbusgw.sendRequest((byte)0x5b, (byte)80);
+		try {
+			mbusgw.sendRequest((byte)0x5b, (byte)80);
 
-		byte[] frame = mbusgw.collectResponse();
-		for (byte x : frame) {
-			System.out.print(Integer.toHexString(Byte.toUnsignedInt(x)) + " ");
+			byte[] frame = mbusgw.collectResponse();
+			for (byte x : frame) {
+				System.out.print(Integer.toHexString(Byte.toUnsignedInt(x)) + " ");
+			}
+			System.out.println();
+		} catch (IOException e) {
+			logger.error("Error in Meterbus dialog: " + e.toString() + ", " + e.getMessage());
 		}
-		System.out.println();
 
 		System.out.println("Stopping mbusgw process");
 		mbusgw.stop();

src/main/java/de/hottis/mbusMaster/MbusgwChild.java

@@ -99,6 +99,10 @@ public class MbusgwChild {
 		int responseCode = Byte.toUnsignedInt(header[0]);
     int responseLen = Byte.toUnsignedInt(header[1]);
     logger.debug("n: " + n + ", h: " + responseCode + ", l: " + responseLen);
+    if (responseCode != 0) {
+      logger.debug("Received error from child: " + responseCode);
+      throw new MbusgwChildException("Error " + responseCode + " from child");
+    }
 		byte[] frame = new byte[responseLen];
     n = this.processInput.read(frame, 0, responseLen);
     logger.debug("frame completely read");

src/main/java/de/hottis/mbusMaster/MbusgwChildException.java

@@ -0,0 +1,21 @@
+package de.hottis.mbusMaster;
+
+import java.io.IOException;
+
+public class MbusgwChildException extends IOException {
+    public MbusgwChildException() {
+        super();
+    }
+
+    public MbusgwChildException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public MbusgwChildException(String message) {
+        super(message);
+    }
+
+    public MbusgwChildException(Throwable cause) {
+        super(cause);
+    }
+}