How to check a Long for null in java

Question

How do I check a Long value for null in Java   Will this work    if   longValue    null    return blah

User · Answer

As primitives long  can t be null It can be converted to wrapper class of that primitive type ie Long  and null check can be performed   If you want to check whether long variable is null you can convert that into Long and check   long longValue null   if Long valueOf longValue   null

User · Answer

If it is Long you can check if it s null unless you go for long  as primitive data types cant be null while Long instance is a object    x000D   x000D  Long num   x000D   x000D  if num    null  return  x000D   x000D   x000D    For some context  you can also prefer using Optional with it to make it somehow beautiful for some use cases  Refer  RequestParam in Spring MVC handling optional parameters

User · Answer

You can check Long object for null value with longValue    null   you can use  longValue    0L for long  primitive   because default value of long is 0L  but it s result will be true if longValue is zero too

User · Answer

If the longValue variable is of type Long  the wrapper class  not the primitive long   then yes you can check for null values   A primitive variable needs to be initialized to some value explicitly  e g  to 0  so its value will never be null

User · Answer

Of course Primitive types cannot be null  But in Java 8 you can use Objects isNull longValue  to check   Ex  If Objects isNull longValue

User · Answer

As mentioned already primitives can not be set to the Object type null   What I do in such cases is just to use -1 or Long MIN VALUE

User · Answer

If it is Long object then You can use longValue    null or you can use  Objects isNull longValue  method in Java 8    Please check Objects for more info

User · Answer

Primitive data types cannot be null   Only Object data types can be null   int  long  etc    can t be null   If you use Long  wrapper class for long  then you can check for null s   Long longValue   null   if longValue    null

[java] How to check a Long for null in java

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