diff --git a/compiler/base/parser/src/main/java/org/onosproject/yang/compiler/parser/impl/parserutils/ListenerUtil.java b/compiler/base/parser/src/main/java/org/onosproject/yang/compiler/parser/impl/parserutils/ListenerUtil.java
index f566545..e2c06a9 100644
--- a/compiler/base/parser/src/main/java/org/onosproject/yang/compiler/parser/impl/parserutils/ListenerUtil.java
+++ b/compiler/base/parser/src/main/java/org/onosproject/yang/compiler/parser/impl/parserutils/ListenerUtil.java
@@ -111,7 +111,7 @@
      */
     public static String removeQuotesAndHandleConcat(String yangStringData) {
 
-        yangStringData = yangStringData.replace("\"", EMPTY_STRING);
+        yangStringData = yangStringData.replaceAll("[\'\"]", EMPTY_STRING);
         String[] tmpData = yangStringData.split(Pattern.quote(ADD));
         StringBuilder builder = new StringBuilder();
         for (String yangString : tmpData) {
diff --git a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ConfigListenerTest.java b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ConfigListenerTest.java
index b7a0d41..123e907 100644
--- a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ConfigListenerTest.java
+++ b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ConfigListenerTest.java
@@ -97,6 +97,11 @@
         // Check whether the Config value is set correctly.
         assertThat(leafInfo.getName(), is("invalid-interval"));
         assertThat(leafInfo.isConfig(), is(false));
+
+        // Check whether the Config value is validated for single quoted boolean
+        leafInfo = leafIterator.next();
+        assertThat(leafInfo.getName(), is("invalid-interval1"));
+        assertThat(leafInfo.isConfig(), is(false));
     }
 
     /**
diff --git a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorAppTagListenerTest.java b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorAppTagListenerTest.java
index 8bd140c..c6b4c33 100644
--- a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorAppTagListenerTest.java
+++ b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorAppTagListenerTest.java
@@ -50,7 +50,7 @@
         YangContainer yangContainer = (YangContainer) yangNode.getChild();
         assertThat(yangContainer.getName(), is("interface"));
 
-        String expectedConstraint = "ifType != 'ethernet' or (ifType = 'ethernet' and ifMTU = 1500)";
+        String expectedConstraint = "ifType != ethernet or (ifType = ethernet and ifMTU = 1500)";
         List<YangMust> mustConstraintList = yangContainer.getListOfMust();
         assertThat(mustConstraintList.iterator().next().getConstraint(), is(expectedConstraint));
 
@@ -72,7 +72,7 @@
         YangContainer yangContainer = (YangContainer) yangNode.getChild();
         assertThat(yangContainer.getName(), is("interface"));
 
-        String expectedConstraint = "ifType != 'ethernet' or (ifType = 'ethernet' and ifMTU = 1500)";
+        String expectedConstraint = "ifType != ethernet or (ifType = ethernet and ifMTU = 1500)";
         List<YangMust> mustConstraintList = yangContainer.getListOfMust();
         assertThat(mustConstraintList.iterator().next().getConstraint(), is(expectedConstraint));
 
diff --git a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorMessageListnerTest.java b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorMessageListnerTest.java
index 7080ef4..a14da2f 100644
--- a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorMessageListnerTest.java
+++ b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/ErrorMessageListnerTest.java
@@ -50,7 +50,7 @@
         YangContainer yangContainer = (YangContainer) yangNode.getChild();
         assertThat(yangContainer.getName(), is("interface"));
 
-        String expectedConstraint = "ifType != 'ethernet' or (ifType = 'ethernet' and ifMTU = 1500)";
+        String expectedConstraint = "ifType != ethernet or (ifType = ethernet and ifMTU = 1500)";
         List<YangMust> mustConstraintList = yangContainer.getListOfMust();
         assertThat(mustConstraintList.iterator().next().getConstraint(), is(expectedConstraint));
 
diff --git a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/MustListenerTest.java b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/MustListenerTest.java
index 2793420..93c1376 100644
--- a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/MustListenerTest.java
+++ b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/MustListenerTest.java
@@ -52,7 +52,7 @@
         YangContainer yangContainer = (YangContainer) yangNode.getChild();
         assertThat(yangContainer.getName(), is("interface"));
 
-        String expectedConstraint = "ifType != 'ethernet' or (ifType = 'ethernet' and ifMTU = 1500)";
+        String expectedConstraint = "ifType != ethernet or (ifType = ethernet and ifMTU = 1500)";
         List<YangMust> mustConstraintList = yangContainer.getListOfMust();
         assertThat(mustConstraintList.iterator().next().getConstraint(), is(expectedConstraint));
     }
@@ -70,7 +70,7 @@
         ListIterator<YangLeaf> leafIterator = yangNode.getListOfLeaf().listIterator();
         YangLeaf leafInfo = leafIterator.next();
 
-        assertThat(leafInfo.getListOfMust().iterator().next().getConstraint(), is("ifType != 'ethernet'"));
+        assertThat(leafInfo.getListOfMust().iterator().next().getConstraint(), is("ifType != ethernet"));
     }
 
     /**
diff --git a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/WhenListenerTest.java b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/WhenListenerTest.java
index c673b1a..00f776d 100644
--- a/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/WhenListenerTest.java
+++ b/compiler/base/parser/src/test/java/org/onosproject/yang/compiler/parser/impl/listeners/WhenListenerTest.java
@@ -49,7 +49,7 @@
         assertThat(yangNode.getName(), is("Test"));
 
         YangList yangList = (YangList) yangNode.getChild();
-        String expectedConstraint = "../switching-capability = 'TDM'";
+        String expectedConstraint = "../switching-capability = TDM";
         assertThat(yangList.getName(), is("interface-switching-capability"));
         assertThat(yangList.getWhen().getCondition(), is(expectedConstraint));
 
@@ -71,6 +71,6 @@
         ListIterator<YangLeaf> leafIterator = yangNode.getListOfLeaf().listIterator();
         YangLeaf leafInfo = leafIterator.next();
 
-        assertThat(leafInfo.getWhen().getCondition(), is("ifType != 'ethernet'"));
+        assertThat(leafInfo.getWhen().getCondition(), is("ifType != ethernet"));
     }
 }
\ No newline at end of file
diff --git a/compiler/base/parser/src/test/resources/ConfigFalse.yang b/compiler/base/parser/src/test/resources/ConfigFalse.yang
index 79dc5ac..b465848 100644
--- a/compiler/base/parser/src/test/resources/ConfigFalse.yang
+++ b/compiler/base/parser/src/test/resources/ConfigFalse.yang
@@ -11,4 +11,13 @@
         status current;
         reference "RFC 6020";
     }
+    leaf invalid-interval1 {
+            type "uint16";
+            units "seconds";
+            description "Interval before a route is declared invalid";
+            config 'false';
+            mandatory 'true';
+            status current;
+            reference "RFC 6020";
+        }
 }
\ No newline at end of file
diff --git a/compiler/base/parser/src/test/resources/ContainerSubStatementErrorAppTag.yang b/compiler/base/parser/src/test/resources/ContainerSubStatementErrorAppTag.yang
index 644b890..1b03523 100644
--- a/compiler/base/parser/src/test/resources/ContainerSubStatementErrorAppTag.yang
+++ b/compiler/base/parser/src/test/resources/ContainerSubStatementErrorAppTag.yang
@@ -12,8 +12,8 @@
         leaf ifMTU {
             type uint32;
         }
-        must "ifType != 'ethernet' or " +
-             "(ifType = 'ethernet' and ifMTU = 1500)" {
+        must "ifType != ethernet or " +
+             "(ifType = ethernet and ifMTU = 1500)" {
             description "An ethernet MTU must be 1500";
             error-app-tag "An ethernet MTU must be 1500";
         }
diff --git a/compiler/base/parser/src/test/resources/ContainerSubStatementErrorDefaultAppTag.yang b/compiler/base/parser/src/test/resources/ContainerSubStatementErrorDefaultAppTag.yang
index c265ea2..3edf457 100644
--- a/compiler/base/parser/src/test/resources/ContainerSubStatementErrorDefaultAppTag.yang
+++ b/compiler/base/parser/src/test/resources/ContainerSubStatementErrorDefaultAppTag.yang
@@ -12,8 +12,8 @@
         leaf ifMTU {
             type uint32;
         }
-        must "ifType != 'ethernet' or " +
-             "(ifType = 'ethernet' and ifMTU = 1500)" {
+        must "ifType != ethernet or " +
+             "(ifType = ethernet and ifMTU = 1500)" {
             description "An ethernet MTU must be 1500";
         }
         must "ifType != 'atm' or " +
diff --git a/compiler/base/parser/src/test/resources/ContainerSubStatementErrorMessage.yang b/compiler/base/parser/src/test/resources/ContainerSubStatementErrorMessage.yang
index 4726d0c..8de1660 100644
--- a/compiler/base/parser/src/test/resources/ContainerSubStatementErrorMessage.yang
+++ b/compiler/base/parser/src/test/resources/ContainerSubStatementErrorMessage.yang
@@ -12,8 +12,8 @@
         leaf ifMTU {
             type uint32;
         }
-        must "ifType != 'ethernet' or " +
-             "(ifType = 'ethernet' and ifMTU = 1500)" {
+        must "ifType != ethernet or " +
+             "(ifType = ethernet and ifMTU = 1500)" {
             description "An ethernet MTU must be 1500";
             error-message "An ethernet MTU must be 1500";
         }
diff --git a/compiler/base/parser/src/test/resources/ContainerSubStatementMust.yang b/compiler/base/parser/src/test/resources/ContainerSubStatementMust.yang
index c089850..de450fc 100644
--- a/compiler/base/parser/src/test/resources/ContainerSubStatementMust.yang
+++ b/compiler/base/parser/src/test/resources/ContainerSubStatementMust.yang
@@ -12,8 +12,8 @@
         leaf ifMTU {
             type uint32;
         }
-        must "ifType != 'ethernet' or " +
-             "(ifType = 'ethernet' and ifMTU = 1500)" {
+        must "ifType != ethernet or " +
+             "(ifType = ethernet and ifMTU = 1500)" {
             description "An ethernet MTU must be 1500";
         }
         must "ifType != 'atm' or " +
diff --git a/compiler/base/parser/src/test/resources/ContainerSubStatementWhen.yang b/compiler/base/parser/src/test/resources/ContainerSubStatementWhen.yang
index c25b499..84757ab 100644
--- a/compiler/base/parser/src/test/resources/ContainerSubStatementWhen.yang
+++ b/compiler/base/parser/src/test/resources/ContainerSubStatementWhen.yang
@@ -3,7 +3,7 @@
     namespace "http://huawei.com";
     prefix Ant;
     list interface-switching-capability {
-         when "../switching-capability = 'TDM'" {
+         when "../switching-capability = TDM" {
                  description "Valid only for TDM";
          }
          key "switching-capability";
@@ -22,7 +22,7 @@
          }
      }
      container time-division-multiplex-capable {
-         when "../switching-capability = 'TDM'" {
+         when "../switching-capability = TDM" {
              description "Valid only for TDM";
          }
          description
diff --git a/compiler/base/parser/src/test/resources/LeafSubStatementMust.yang b/compiler/base/parser/src/test/resources/LeafSubStatementMust.yang
index 6d7e626..1a2c0c1 100644
--- a/compiler/base/parser/src/test/resources/LeafSubStatementMust.yang
+++ b/compiler/base/parser/src/test/resources/LeafSubStatementMust.yang
@@ -7,7 +7,7 @@
             enum ethernet;
             enum atm;
         }
-        must "ifType != 'ethernet'" {
+        must "ifType != ethernet" {
             description "ifType is not ethernet";
         }
     }
diff --git a/compiler/base/parser/src/test/resources/LeafSubStatementWhen.yang b/compiler/base/parser/src/test/resources/LeafSubStatementWhen.yang
index 239e0b6..f980763 100644
--- a/compiler/base/parser/src/test/resources/LeafSubStatementWhen.yang
+++ b/compiler/base/parser/src/test/resources/LeafSubStatementWhen.yang
@@ -3,7 +3,7 @@
     namespace http://huawei.com;
     prefix Ant;
     leaf ifType {
-        when "ifType != 'ethernet'" {
+        when "ifType != ethernet" {
             description "ifType is not ethernet";
         }
         type enumeration {