java.lang.IllegalArgumentException: Wildcard string cannot be null or empty.

Today, the problem encountered in the project development process; java.lang.IllegalArgumentException: Wildcard string can not be null or empty.

Cause of the error, in doing certification, there is null

Subject subject = SecurityUtils.getSubject();
ActiveUser activeUser = (ActiveUser) subject.getPrincipal();

原因一：
activeUser.getPermissions() == null

原因二：

List<SysPermission> permissions = activeUser.getPermissions();

permissions 里值存在null

运行 if( !subject.isPermitted(permissions) )会报错

　　Solution

// Causes a solution: 
// custom realm in value added permissionList 
activeUser.setPermissions (permissionList); 


// solution for two reasons: 
// null value in the Permissions remove, or change it in code database content scheduling