diff --git a/src/main/java/com/googlecode/aviator/runtime/function/system/BigIntFunction.java b/src/main/java/com/googlecode/aviator/runtime/function/system/BigIntFunction.java
index aee6d8e4..e3b5b015 100644
--- a/src/main/java/com/googlecode/aviator/runtime/function/system/BigIntFunction.java
+++ b/src/main/java/com/googlecode/aviator/runtime/function/system/BigIntFunction.java
@@ -36,7 +36,7 @@ public AviatorObject call(final Map<String, Object> env, final AviatorObject arg
         } else if (obj instanceof Character) {
           return AviatorBigInt.valueOf(new BigInteger(String.valueOf(obj)));
         } else {
-          throw new ClassCastException("Could not cast " + obj.getClass().getName() + " to bigint");
+          throw new ClassCastException("Could not cast " + (obj != null ? obj.getClass().getName() : "null")  + " to bigint, AviatorObject is " + arg1);
         }
       case String:
         return AviatorBigInt.valueOf(new BigInteger((String) arg1.getValue(env)));
diff --git a/src/main/java/com/googlecode/aviator/runtime/function/system/DoubleFunction.java b/src/main/java/com/googlecode/aviator/runtime/function/system/DoubleFunction.java
index 50e5b025..0a44f73c 100644
--- a/src/main/java/com/googlecode/aviator/runtime/function/system/DoubleFunction.java
+++ b/src/main/java/com/googlecode/aviator/runtime/function/system/DoubleFunction.java
@@ -34,7 +34,7 @@ public AviatorObject call(Map<String, Object> env, AviatorObject arg1) {
         } else if (obj instanceof Character) {
           return new AviatorDouble(Double.parseDouble(String.valueOf(obj)));
         } else {
-          throw new ClassCastException("Could not cast " + obj.getClass().getName() + " to double");
+          throw new ClassCastException("Could not cast " + (obj != null ? obj.getClass().getName() : "null")  + " to double, AviatorObject is" + arg1 );
         }
       case String:
         return new AviatorDouble(Double.parseDouble((String) arg1.getValue(env)));
diff --git a/src/main/java/com/googlecode/aviator/runtime/function/system/LongFunction.java b/src/main/java/com/googlecode/aviator/runtime/function/system/LongFunction.java
index 5b30aa7e..07ff6fd6 100644
--- a/src/main/java/com/googlecode/aviator/runtime/function/system/LongFunction.java
+++ b/src/main/java/com/googlecode/aviator/runtime/function/system/LongFunction.java
@@ -34,7 +34,7 @@ public AviatorObject call(Map<String, Object> env, AviatorObject arg1) {
         } else if (obj instanceof Character) {
           return AviatorLong.valueOf(Long.valueOf(String.valueOf(obj)));
         } else {
-          throw new ClassCastException("Could not cast " + obj.getClass().getName() + " to long");
+          throw new ClassCastException("Could not cast " + (obj != null ? obj.getClass().getName() : "null")  + " to long, AviatorObject is " + arg1);
         }
       case String:
         return AviatorLong.valueOf(Long.valueOf((String) arg1.getValue(env)));
diff --git a/src/test/java/com/googlecode/aviator/runtime/function/system/BigIntFunctionUnitTest.java b/src/test/java/com/googlecode/aviator/runtime/function/system/BigIntFunctionUnitTest.java
new file mode 100644
index 00000000..ecf2e382
--- /dev/null
+++ b/src/test/java/com/googlecode/aviator/runtime/function/system/BigIntFunctionUnitTest.java
@@ -0,0 +1,27 @@
+package com.googlecode.aviator.runtime.function.system;
+
+import com.googlecode.aviator.runtime.type.AviatorJavaType;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+public class BigIntFunctionUnitTest {
+    @Test(expected = ClassCastException.class)
+    public void testCall_WithJavaTypeNullArgument() {
+        BigIntFunction bigIntFunction = new BigIntFunction();
+        AviatorJavaType aviatorJavaType = new AviatorJavaType("var");
+        bigIntFunction.call(null, aviatorJavaType);
+    }
+
+    @Test(expected = ClassCastException.class)
+    public void testCall_WithJavaTypeNotSupportArgument() {
+        BigIntFunction bigIntFunction = new BigIntFunction();
+        AviatorJavaType aviatorJavaType = new AviatorJavaType("var");
+        Map<String, Object> env = new HashMap<>();
+        env.put("var", true);
+
+        bigIntFunction.call(env, aviatorJavaType);
+    }
+}
diff --git a/src/test/java/com/googlecode/aviator/runtime/function/system/DoubleFunctionUnitTest.java b/src/test/java/com/googlecode/aviator/runtime/function/system/DoubleFunctionUnitTest.java
new file mode 100644
index 00000000..2c153ae7
--- /dev/null
+++ b/src/test/java/com/googlecode/aviator/runtime/function/system/DoubleFunctionUnitTest.java
@@ -0,0 +1,27 @@
+package com.googlecode.aviator.runtime.function.system;
+
+import com.googlecode.aviator.runtime.type.AviatorJavaType;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+public class DoubleFunctionUnitTest {
+    @Test(expected = ClassCastException.class)
+    public void testCall_WithJavaTypeNullArgument() {
+        DoubleFunction doubleFunction = new DoubleFunction();
+        AviatorJavaType aviatorJavaType = new AviatorJavaType("var");
+        doubleFunction.call(null, aviatorJavaType);
+    }
+
+    @Test(expected = ClassCastException.class)
+    public void testCall_WithJavaTypeNotSupportArgument() {
+        DoubleFunction doubleFunction = new DoubleFunction();
+        AviatorJavaType aviatorJavaType = new AviatorJavaType("var");
+        Map<String, Object> env = new HashMap<>();
+        env.put("var", true);
+
+        doubleFunction.call(env, aviatorJavaType);
+    }
+}
diff --git a/src/test/java/com/googlecode/aviator/runtime/function/system/LongFunctionUnitTest.java b/src/test/java/com/googlecode/aviator/runtime/function/system/LongFunctionUnitTest.java
new file mode 100644
index 00000000..106f22ed
--- /dev/null
+++ b/src/test/java/com/googlecode/aviator/runtime/function/system/LongFunctionUnitTest.java
@@ -0,0 +1,27 @@
+package com.googlecode.aviator.runtime.function.system;
+
+import com.googlecode.aviator.runtime.type.AviatorJavaType;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+public class LongFunctionUnitTest {
+    @Test(expected = ClassCastException.class)
+    public void testCall_WithJavaTypeNullArgument() {
+        LongFunction longFunction = new LongFunction();
+        AviatorJavaType aviatorJavaType = new AviatorJavaType("var");
+        longFunction.call(null, aviatorJavaType);
+    }
+
+    @Test(expected = ClassCastException.class)
+    public void testCall_WithJavaTypeNotSupportArgument() {
+        LongFunction longFunction = new LongFunction();
+        AviatorJavaType aviatorJavaType = new AviatorJavaType("var");
+        Map<String, Object> env = new HashMap<>();
+        env.put("var", true);
+
+        longFunction.call(env, aviatorJavaType);
+    }
+}