Home/ Questions/Q 6956783
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-27T14:54:53+00:00

what happens in memory when I, say, do the following: in C: char *c=NULL;

  • 0

what happens in memory when I, say, do the following:
in C: char *c=NULL;
in java: MyClass mc=null;
what happens in memory, how is this null represented in memory in both of these languages? Thanks

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    In C you are basically setting the pointer to zero value. In fact

    char *c = NULL;

    is equivalent to

    char *c = 0;

    Zero pointer cannot be dereferenced since there is no memory mapping for this address. On platforms with virtual memory, an attempt to do so triggers a page fault transferring control to the operating system which then usually handles the situation by killing the offending process (in UNIX your process receives Segmentation Violation signal SIGSEGV).

    In Java, all non-primitive type variables are references. null in Java is a literal denoting the only value of a special unnamed type. This type can be cast to any reference type allowing you to put null into any reference variable. An attempt to use such reference to access an object will throw an unchecked exception called NullPointerException. See JLS 3.10.7 and JLS 4.1 for details.

    • 0