[ONOS-5085][ONOS-5086][ONOS-5199][ONOS-5212] Yang application broker implemetation

Change-Id: I22f2ab0d98ae43fc8c0ab65d6dbf581fcd76bd47
diff --git a/apps/yms/app/src/main/java/org/onosproject/yms/app/yab/exceptions/YabException.java b/apps/yms/app/src/main/java/org/onosproject/yms/app/yab/exceptions/YabException.java
new file mode 100644
index 0000000..846276c
--- /dev/null
+++ b/apps/yms/app/src/main/java/org/onosproject/yms/app/yab/exceptions/YabException.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.yms.app.yab.exceptions;
+
+/**
+ * Represents base class for exceptions in YDT operations.
+ */
+public class YabException extends RuntimeException {
+
+    private static final long serialVersionUID = 20160211L;
+
+    /**
+     * Creates a new YDT exception.
+     */
+    public YabException() {
+    }
+
+    /**
+     * Creates a new YDT exception with given message.
+     *
+     * @param message the detail of exception in string
+     */
+    public YabException(String message) {
+        super(message);
+    }
+
+    /**
+     * Creates a new YDT exception from given message and cause.
+     *
+     * @param message the detail of exception in string
+     * @param cause   underlying cause of the error
+     */
+    public YabException(final String message, final Throwable cause) {
+        super(message, cause);
+    }
+
+    /**
+     * Creates a new YDT exception from cause.
+     *
+     * @param cause underlying cause of the error
+     */
+    public YabException(final Throwable cause) {
+        super(cause);
+    }
+}