fix error message

src/main/java/com/github/sidhant92/boolparser/exception/DataNotFoundException.java

@@ -6,9 +6,4 @@ public class DataNotFoundException extends RuntimeException {
     public DataNotFoundException(final String key) {
         super(String.format(MESSAGE + " for the key %s", key));
     }
-
-    @Override
-    public String getMessage() {
-        return MESSAGE;
-    }
 }

src/main/java/com/github/sidhant92/boolparser/exception/InvalidContainerTypeException.java

@@ -8,9 +8,4 @@ public InvalidContainerTypeException(final String message) {
     public InvalidContainerTypeException() {
         super();
     }
-
-    @Override
-    public String getMessage() {
-        return "Invalid Container Type";
-    }
 }

src/main/java/com/github/sidhant92/boolparser/exception/InvalidDataType.java

@@ -8,9 +8,4 @@ public InvalidDataType(final String message) {
     public InvalidDataType() {
         super();
     }
-
-    @Override
-    public String getMessage() {
-        return "Invalid Data Type";
-    }
 }

src/main/java/com/github/sidhant92/boolparser/exception/InvalidExpressionException.java

@@ -4,9 +4,4 @@ public class InvalidExpressionException extends RuntimeException {
     public InvalidExpressionException(final String message) {
         super(message);
     }
-
-    @Override
-    public String getMessage() {
-        return "Invalid Expression";
-    }
 }

src/main/java/com/github/sidhant92/boolparser/exception/UnsupportedToken.java

@@ -10,9 +10,4 @@ public UnsupportedToken(final String token) {
     public UnsupportedToken() {
         super();
     }
-
-    @Override
-    public String getMessage() {
-        return MESSAGE;
-    }
 }