diff --git a/src/sandbox/GeneralCompare.java b/src/sandbox/GeneralCompare.java
new file mode 100644
index 0000000000000000000000000000000000000000..29332aa981890f0b026d7bc1bdca632304f21563
--- /dev/null
+++ b/src/sandbox/GeneralCompare.java
@@ -0,0 +1,5 @@
+package sandbox;
+
+public interface GeneralCompare<T> {
+	public int eval(T a1, T a2);
+}
diff --git a/src/sandbox/TestLambdas.java b/src/sandbox/TestLambdas.java
index 69ac2bc4ac76ff8d89bbf350715f975842e96eef..91dc35c0120ef2193dd16f11cc8e5e4a4c8f975e 100644
--- a/src/sandbox/TestLambdas.java
+++ b/src/sandbox/TestLambdas.java
@@ -7,9 +7,9 @@ package sandbox;
 public class TestLambdas {
 	public static void main(String[] args) {
 		//declare the instances of BinaryIntExpression
-		BinaryIntExpression b0;
-		BinaryIntExpression b1;
-		BinaryIntExpression b2;
+		GeneralCompare<Integer> b0;
+		GeneralCompare<Integer> b1;
+		GeneralCompare<Integer> b2;
 		BinaryIntExpression b3;
 		BinaryIntExpression b4;
 		BinaryIntExpression b5;
@@ -34,13 +34,13 @@ public class TestLambdas {
 		};
 			
 		//call the main function using the instances as a parameter.
-		result = binaryOperation(1,2,b0);
+		result = binaryIntegerOperation(1,2,b0);
 		System.out.println(result);
 		
-		result = binaryOperation(1,2,b1);
+		result = binaryIntegerOperation(1,2,b1);
 		System.out.println(result);
 		
-		result = binaryOperation(1,2,b2);
+		result = binaryIntegerOperation(1,2,b2);
 		System.out.println(result);
 		
 		result = binaryOperation(1,2,b3);
@@ -61,4 +61,9 @@ public class TestLambdas {
 		return exp.eval(a1, a2);
 	}
 	
+	public static int binaryIntegerOperation(int a1, int a2, GeneralCompare<Integer> exp) {
+		//call the eval() function in the given BinaryIntExpression.
+		return exp.eval(a1, a2);
+	}
+	
 }