diff --git a/src/main/java/no/birkett/kiwi/DuplicateConstraintException.java b/src/main/java/no/birkett/kiwi/DuplicateConstraintException.java
index c5a8c37..ab47d8c 100644
--- a/src/main/java/no/birkett/kiwi/DuplicateConstraintException.java
+++ b/src/main/java/no/birkett/kiwi/DuplicateConstraintException.java
@@ -3,9 +3,11 @@ package no.birkett.kiwi;
 /**
  * Created by alex on 30/01/15.
  */
-public class DuplicateConstraintException extends Exception {
+public class DuplicateConstraintException extends KiwiException {
+
+    private Constraint constraint;
 
     public DuplicateConstraintException(Constraint constraint) {
-
+        this.constraint = constraint;
     }
 }
diff --git a/src/main/java/no/birkett/kiwi/DuplicateEditVariableException.java b/src/main/java/no/birkett/kiwi/DuplicateEditVariableException.java
index b951b4e..fa06bc2 100644
--- a/src/main/java/no/birkett/kiwi/DuplicateEditVariableException.java
+++ b/src/main/java/no/birkett/kiwi/DuplicateEditVariableException.java
@@ -3,6 +3,6 @@ package no.birkett.kiwi;
 /**
  * Created by yongsun on 1/13/16.
  */
-public class DuplicateEditVariableException extends Exception {
+public class DuplicateEditVariableException extends KiwiException {
 
 }
diff --git a/src/main/java/no/birkett/kiwi/InternalSolverError.java b/src/main/java/no/birkett/kiwi/InternalSolverError.java
index 61694ab..c605cb3 100644
--- a/src/main/java/no/birkett/kiwi/InternalSolverError.java
+++ b/src/main/java/no/birkett/kiwi/InternalSolverError.java
@@ -3,7 +3,7 @@ package no.birkett.kiwi;
 /**
  * Created by alex on 31/01/15.
  */
-public class InternalSolverError extends RuntimeException {
+public class InternalSolverError extends Error {
     
     public InternalSolverError(String string) {
 
diff --git a/src/main/java/no/birkett/kiwi/KiwiException.java b/src/main/java/no/birkett/kiwi/KiwiException.java
new file mode 100644
index 0000000..b8c8df4
--- /dev/null
+++ b/src/main/java/no/birkett/kiwi/KiwiException.java
@@ -0,0 +1,10 @@
+package no.birkett.kiwi;
+
+/**
+ * Created by alex on 30/01/16.
+ */
+public class KiwiException extends Exception {
+    public KiwiException() {
+
+    }
+}
diff --git a/src/main/java/no/birkett/kiwi/NonlinearExpressionException.java b/src/main/java/no/birkett/kiwi/NonlinearExpressionException.java
index 48e1600..40972ee 100644
--- a/src/main/java/no/birkett/kiwi/NonlinearExpressionException.java
+++ b/src/main/java/no/birkett/kiwi/NonlinearExpressionException.java
@@ -3,5 +3,5 @@ package no.birkett.kiwi;
 /**
  * Created by alex on 01/02/15.
  */
-public class NonlinearExpressionException extends RuntimeException {
+public class NonlinearExpressionException extends KiwiException {
 }
diff --git a/src/main/java/no/birkett/kiwi/RequiredFailureException.java b/src/main/java/no/birkett/kiwi/RequiredFailureException.java
index dc5524b..d9b221a 100644
--- a/src/main/java/no/birkett/kiwi/RequiredFailureException.java
+++ b/src/main/java/no/birkett/kiwi/RequiredFailureException.java
@@ -3,5 +3,5 @@ package no.birkett.kiwi;
 /**
  * Created by alex on 30/01/15.
  */
-public class RequiredFailureException extends Exception {
+public class RequiredFailureException extends KiwiException {
 }
diff --git a/src/main/java/no/birkett/kiwi/UnknownConstraintException.java b/src/main/java/no/birkett/kiwi/UnknownConstraintException.java
index 6f1384a..4f967df 100644
--- a/src/main/java/no/birkett/kiwi/UnknownConstraintException.java
+++ b/src/main/java/no/birkett/kiwi/UnknownConstraintException.java
@@ -3,7 +3,7 @@ package no.birkett.kiwi;
 /**
  * Created by yongsun on 1/13/16.
  */
-public class UnknownConstraintException extends Exception {
+public class UnknownConstraintException extends KiwiException {
 
     public UnknownConstraintException(Constraint constraint){
 
diff --git a/src/main/java/no/birkett/kiwi/UnsatisfiableConstraintException.java b/src/main/java/no/birkett/kiwi/UnsatisfiableConstraintException.java
index 4d36c7a..4b174dd 100644
--- a/src/main/java/no/birkett/kiwi/UnsatisfiableConstraintException.java
+++ b/src/main/java/no/birkett/kiwi/UnsatisfiableConstraintException.java
@@ -3,8 +3,10 @@ package no.birkett.kiwi;
 /**
  * Created by alex on 30/01/15.
  */
-public class UnsatisfiableConstraintException extends Exception {
-    public UnsatisfiableConstraintException(Constraint constraint) {
+public class UnsatisfiableConstraintException extends KiwiException {
 
+    private Constraint constraint;
+    public UnsatisfiableConstraintException(Constraint constraint) {
+        this.constraint = constraint;
     }
 }
diff --git a/src/test/java/no/birkett/kiwi/Benchmarks.java b/src/test/java/no/birkett/kiwi/Benchmarks.java
index 198f258..0ebc11f 100644
--- a/src/test/java/no/birkett/kiwi/Benchmarks.java
+++ b/src/test/java/no/birkett/kiwi/Benchmarks.java
@@ -7,7 +7,7 @@ import java.util.HashMap;
  */
 public class Benchmarks {
 
-    public static void testAddingLotsOfConstraints() throws DuplicateConstraintException, UnsatisfiableConstraintException {
+    public static void testAddingLotsOfConstraints() throws DuplicateConstraintException, UnsatisfiableConstraintException, NonlinearExpressionException {
         Solver solver = new Solver();
 
         final HashMap<String, Variable> variables = new HashMap<String, Variable>();
@@ -65,6 +65,8 @@ public class Benchmarks {
             e.printStackTrace();
         } catch (UnsatisfiableConstraintException e) {
             e.printStackTrace();
+        } catch (NonlinearExpressionException e) {
+            e.printStackTrace();
         }
     }
 
diff --git a/src/test/java/no/birkett/kiwi/ConstraintParser.java b/src/test/java/no/birkett/kiwi/ConstraintParser.java
index b941d98..66908db 100644
--- a/src/test/java/no/birkett/kiwi/ConstraintParser.java
+++ b/src/test/java/no/birkett/kiwi/ConstraintParser.java
@@ -19,7 +19,7 @@ public class ConstraintParser {
         Expression resolveConstant(String name);
     }
 
-    public static Constraint parseConstraint(String constraintString, CassowaryVariableResolver variableResolver) {
+    public static Constraint parseConstraint(String constraintString, CassowaryVariableResolver variableResolver) throws NonlinearExpressionException {
 
         Matcher matcher = pattern.matcher(constraintString);
         matcher.find();
@@ -63,7 +63,7 @@ public class ConstraintParser {
         return strength;
     }
 
-    public static Expression resolveExpression(String expressionString, CassowaryVariableResolver variableResolver) {
+    public static Expression resolveExpression(String expressionString, CassowaryVariableResolver variableResolver) throws NonlinearExpressionException {
 
         List<String> postFixExpression = infixToPostfix(tokenizeExpression(expressionString));
 
diff --git a/src/test/java/no/birkett/kiwi/RealWorldTests.java b/src/test/java/no/birkett/kiwi/RealWorldTests.java
index edc60f8..1bba3b5 100644
--- a/src/test/java/no/birkett/kiwi/RealWorldTests.java
+++ b/src/test/java/no/birkett/kiwi/RealWorldTests.java
@@ -202,7 +202,7 @@ public class RealWorldTests {
     }
 
     @Test
-    public void testGridLayout() throws DuplicateConstraintException, UnsatisfiableConstraintException {
+    public void testGridLayout() throws DuplicateConstraintException, UnsatisfiableConstraintException, NonlinearExpressionException {
 
         final Solver solver = new Solver();
         final HashMap<String, HashMap<String, Variable>> nodeHashMap = new HashMap<>();
@@ -321,7 +321,7 @@ public class RealWorldTests {
 */
   
     @Test
-    public void testGridX1000() throws DuplicateConstraintException, UnsatisfiableConstraintException {
+    public void testGridX1000() throws DuplicateConstraintException, UnsatisfiableConstraintException, NonlinearExpressionException {
 
         long nanoTime = System.nanoTime();
         for (int i = 0; i < 1000; i++) {