#fixed code
                                public void setSqlSource(MappedStatement ms) {
        MapperTemplate mapperTemplate = getMapperTemplate(ms.getId());
        try {
            if (mapperTemplate != null) {
                mapperTemplate.setSqlSource(ms);
            }
        } catch (Exception e) {
            throw new RuntimeException("调用方法异常:" + e.getMessage());
        }
    }
#vulnerable code 
                                public void setSqlSource(MappedStatement ms) {
        MapperTemplate mapperTemplate = getMapperTemplate(ms.getId());
        try {
            mapperTemplate.setSqlSource(ms);
        } catch (Exception e) {
            throw new RuntimeException("调用方法异常:" + e.getMessage());
        }
    } 
                            #location 4 
                            #vulnerability type NULL_DEREFERENCE