java自定义错误类

java自定义异常类
public class MyFirstException extends Exception {
public MyFirstException() {
  super();
}
public MyFirstException(String msg) {
  super(msg);
}
public MyFirstException(String msg, Throwable cause) {
  super(msg, cause);
}
public MyFirstException(Throwable cause) {
  super(cause);
}