Checking the long value is null or not

Question

Hi
Can anybody help me how to check that a long variable is null ot not?

Answer 1

karthikeyan.v wrote:
its ok...but reply me that how to check a long variable contains any content?If your code compiles, it always has predictable "content" (value).
class Foo {
  long z; // 1
  void bar() {
    long y; // 2
    // 3
    long x = y; // 4
}Because of #1, every time you create a Foo object that object's z variable has a value of 0 after construction has finished. Member variables are initialized to 0/false/null before you can even see them.
Local variables, however, do not have a value until you assign one to them. The compiler knows this, and will not let you use a local unless it has been "definitely assigned" (JLS term) at that point.
Here, because we do not assign a value to y at #2 or any time after that, as of #3 and afterwards, it does not have a value as far as the compiler is concerned. That means when we get to #4, we'll get a compile-time error.
If we get past #4 without a compile-time error, then it is guarnateed that y has been assigned a value by our code in the body of that metohd.
If this does not answer your question, please clarify what you're asking with something more precise and descriptive than "how to check it contains any content", which means nothing.