Java: Can you treat null as the integer 0 as in C?

I want to check how many fields of an object are null. Can I do something like: int numNotNull = !!(obj.a) + !!(obj.b) + !!(obj.c) + !!(obj.d); This would work if null was a pointer to the 0 address, as in C.For a good understanding of what null is i

Does setting the variable to null just erase the reference?

This question already has an answer here: What is the difference between a variable, object, and reference? [duplicate] 5 answers What happens if I do: Object obj = new Object(); obj = null; Does it remove the object from memory, or clear just the re

No warning when returning from NULL with gcc

Using gcc 5.2.0, I noticed that this code does not generate a warning: #include <stddef.h> int function(void) { return NULL; } void procedure(void) { return NULL; } I used the flags -Wall -Wextra -std=c99 -pedantic and I am running archlinux. I am n

How to assign a null value to a variable in PowerShell?

I want to assign a null value to a variable called $dec but it gives me errors, here is my code: import-module activedirectory $domain = "" $dec= null Get-ADComputer -Filter {Description -eq $dec} These are automatic variables,

Null pointer access in the variable inside a for

In the lines marked with $ show the following message: Multiple markers at this line - Null pointer access: The variable InformeSalvaguardasAGR can only be null at this location - Null pointer access: The variable InformeSalvaguardasAGR can only be n

Error with JSP search

Okay I have a huge problem with this. I have spend hours with my group trying to solve this small problem we have on the group project and cant find the answer I either get null pointer exeption or something with org.apache.jasper.jasperexception or

Ruby XML analysis; no exceptions

I've got a Ruby program that parses XML from a website and now and again it crashes when one of the elements is nil. I've implemented the following code to handle it but it doesn't seem to work; begin data[6]= element.elements["company_info"].el

Hashmap get (key) returns null even when the value is present

I'm trying to save datas in a hash map and retrieve it. The value corresponding to the key is present and it still returns null. I have implemented the equals() and hashCode() methods also. ArrayList<Friends> friendsArrayList = new ArrayList<Frie

g ++ and gcc 4.8 can not find null_ptr?

I read somewhere that gcc 4.6 implemented the c++11 null_ptr. I have 4.8 but I can only find std::nullptr_t (which doesnt seem to work the same). What do I need to do/include to use null_ptr in g++ 4.8?std::nullptr_t is the type, and it is available

Request for null using the casbah

I'm using Casbah to connect to and query a Mongo database. Right now I'm trying to query on fields where the value is not null. Using straight Mongo syntax, the query I'm wanting would be collection.find({"key" : {$ne : null }} ) In casbah, I've

Update or insert a value if a field is NULL

I know this is a very simple question but I just wanted to be sure. I have a Null value in a field, and I want to change that Null value. To change the Null Value Do I use Insert or update? For Example: Insert Into dataTable (Column 1) Values (1) WHE

Why is "exception" nowhere visible?

I have a peace of code that is poorly written, like so: HashMap<String, TceFile> mapPresetLastKdf = new HashMap<String, TceFile>( (HashMap<String, TceFile>) RsessionVars.get( sessionVars, Constants.SVAR_ENC_PRESET_LAST_KDF_MAP ) ); HashM

how to test empty / null values ​​in XML with php

I have a webservice from where I retrieve informations before updating a database. I have to search for some values before inserting them, if i found them, obviously I will not insert them the xml should be like this: <?xml version="1.0" enco

AS3 - Access an object of another class

I have three classes: a Main, a Player and a Car. The main creates a Car and a Player. The Car needs to trace the player's x position. But the code below is not working. I have researched and found that declaring it as static should fix the problem a

Absolute positioning of a JButton

I am trying to position a JButton with a null layout but it will not show up, if i switch to gridlayout they are only lined up in the middle no matter what i change. How can i set the position and size of my button? In Frame package Run; import javax

HQL: LIKE in null relation

I have a OneToMany relationship: public class Class1{ private String attr1; private String attr2; @OneToOne private Class2 object1; } public class Class2{ private String attr3; } The relationship can store null objects (I mean that an instance of Cla

Type of the null value using F #

Is there any way to get a type of the null value? This does not work: let a: string = null let typ = a.GetType() Thanks let getStaticType<'T>(_x : 'T) = typeof<'T> let a : string = null let b : int[] = null let typ1 = getStaticType a let typ2

LINQ - Update null entire data field

I have got a field with data type int? price and allow null, when I set book.price = null; and update, it is not saved and does not throw any exceptions, when I change value # null, it is ok. I want set it null.Make sure the field is nullable in the

.NET DBNull vs Nothing on all types of variables?

I am a little confused about null values and variables in .NET. (VB preferred) Is there any way to check the "nullness" of ANY given variable regardless of whether it was an object or a value type? Or does my null check have to always anticipate

Null object model in Objective-C

In Java, it is very easy to code the following design: public abstract class Pizza { public static final Pizza.NULL = new Pizza() { /* "null" implementations */ } /* actual/abstract implmentations */ } What is the preferred method to attain the