NullPointerException、ArrayIndexOutOfBoundsException、ClassCastException、ArrayIndexOutOfBoundsException、ArrayStoreException、ArithmeticException null 无堆栈信息

今天工作中，临时Fix一个bug，一看日志“java.lang.ClassCastException: null”相当懵逼，没有详细堆栈信息，这咋整。虽然根据上下文可以推测代码的大致位置，但不敢拍板确认啊。只好google找一下，在Stackoverflow上果然有解决办法

【解决方法】在java启动命令中添加“-XX:-OmitStackTraceInFastThrow”即可输出详细堆栈信息——亲测可用。

【问题原因】如果同一个错误的日志频繁发生，为了性能优化，同时不至于同样的堆栈日志频繁刷入到日志文件，让日志文件巨增，【CoederBaby】JVM在输出一定次数的异常堆栈后，就会省略堆栈信息

【进一步分析】参看JVM源码（参见附录2），可见这个优化同时试用于以下异常：

  • NullPointerException
  • ArrayIndexOutOfBoundsException
  • ClassCastException
  • ArrayIndexOutOfBoundsException
  • ArrayStoreException
  • ArithmeticException

相关核心代码片段：

  // If this throw happens frequently, an uncommon trap might cause
  // a performance pothole.  If there is a local exception handler,
  // and if this particular bytecode appears to be deoptimizing often,
  // let us handle the throw inline, with a preconstructed instance.
  // Note:   If the deopt count has blown up, the uncommon trap
  // runtime is going to flush this nmethod, not matter what.
  if (treat_throw_as_hot
      && (!StackTraceInThrowable || OmitStackTraceInFastThrow)) {
    // If the throw is local, we use a pre-existing instance and
    // punt on the backtrace.  This would lead to a missing backtrace
    // (a repeat of 4292742) if the backtrace object is ever asked
    // for its backtrace.
    // Fixing this remaining case of 4292742 requires some flavor of
    // escape analysis.  Leave that for the future.
    ciInstance* ex_obj = NULL;
    switch (reason) {
    case Deoptimization::Reason_null_check:
      ex_obj = env()->NullPointerException_instance();
      break;
    case Deoptimization::Reason_div0_check:
      ex_obj = env()->ArithmeticException_instance();
      break;
    case Deoptimization::Reason_range_check:
      ex_obj = env()->ArrayIndexOutOfBoundsException_instance();
      break;
    case Deoptimization::Reason_class_check:
      if (java_bc() == Bytecodes::_aastore) {
        ex_obj = env()->ArrayStoreException_instance();
      } else {
        ex_obj = env()->ClassCastException_instance();
      }
      break;
    default:
      break;
    }

 

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