即使Java不支持指针，但Java为什么会抛出java.lang.NullPointerException: [英] EvenThough Java Does not Support Pointers But Why Java Throws java.lang.NullPointerException:

问题描述

我想知道为什么会这样Bcz我已经多次遇到此异常....

I Want To Know Why This happens Bcz i Have Faced This Exception So many Times....

推荐答案

原因很多.请参考- NullPointerException类 [

There are many reasons. Refer - Class NullPointerException[^].

报价:

当应用程序尝试在
中使用null时抛出 需要对象的情况.其中包括:

• 调用null对象的实例方法.
  
• 访问或修改null对象的字段.
  
• 以null的长度作为数组.
  
• 访问或修改null的插槽，就像它一样
  是一个数组.
  
• 将null视为Throwable
  值.
  

Thrown when an application attempts to use null in a
case where an object is required. These include:

• Calling the instance method of a null object.
  
• Accessing or modifying the field of a null object.
  
• Taking the length of null as if it were an array.
  
• Accessing or modifying the slots of null as if it
  were an array.
  
• Throwing null as if it were a Throwable
  value.
  

应用程序应抛出此类的实例以指示
null对象的其他非法使用. NullPointerException对象可以由虚拟机构造，就像

Applications should throw instances of this class to indicate
other illegal uses of the null object. NullPointerException objects may be constructed by the virtual machine as if suppression were disabled and/or the
stack trace was not writable.

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