In Java I am told that when doing a null check one should use == instead of .equals(). What are the reasons for this?

How can I check for null values in JavaScript? I wrote the code below but it didn't work.

null assigned to this variable was transformed to "null" -- this is a terrible idea. Try to change this design if at all possible.

Feb 16, 2019 · It can be used on a type to control Nullability, it is then called the "Null Forgiving Operator". Basically, null! applies the ! operator to the value null. This overrides the nullability …

In case a.colD is an empty string and b.colID is NULL the comparison would still evaluate to true, even though the two columns contain different values. In some cases you don't want to treat …

A NULL column is not countable, however a row that has a NULL column is. So, this should do what you're looking for: SELECT COUNT (*) FROM TABLE WHERE COL_NAME IS NULL OR …

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine the cause so that you stop the exception from …

This Stack Overflow question discusses the correct way to represent null XML elements.

1 NULL is a special value which explicitly states that the variable has not been set to any value yet. Be careful with using the empty() function as you can't just determine that a variable is …

96 Checking null with normal equality will also return true for undefined. if (window.variable == null) alert('variable is null or undefined');