Added a missing single quote in an exception message (#2644)

* Added a missing single quote in an exception message

* Put the imports back in the correct order

Author: IrvingOS

src/main/java/org/apache/ibatis/binding/MapperMethod.java

@@ -99,7 +99,7 @@ public Object execute(SqlSession sqlSession, Object[] args) {
     }
     if (result == null && method.getReturnType().isPrimitive() && !method.returnsVoid()) {
       throw new BindingException("Mapper method '" + command.getName()
-          + " attempted to return null from a method with a primitive return type (" + method.getReturnType() + ").");
+          + "' attempted to return null from a method with a primitive return type (" + method.getReturnType() + ").");
     }
     return result;
   }