What is the proper way to check for null values?

I love the null-coalescing operator because it makes it easy to assign a default value for nullable types.

How to avoid "!= null' statements in Java?

I work with Java all day long. The most used idiom (code snippet) I'm programming in Java, is to test if an object != null before I use it, to avoid a NullPointerException of course. But the code looks very ugly and becomes unreadable.

What is the difference between null and undefined in JavaScript?

I want to know what the difference is between null and undefined in JavaScript.

Is there a standard function to check for null, undefined, or blank variables in JavaScript?

Is there a universal JavaScript function that checks that a variable has a value and ensures that it's not undefined or null ? I've got this code, but I'm not sure if it covers all cases:

How to replace the string values stored with in a variable in objective c

I got an xml in output for the webservices.I have the result in the variable and i stored the result in that variable.Now i want to replace the strings in that variable.How to replace the strings in that variable. For ex: