Why in Java, (“string”).equals(var) recommended other than (var).equals(“string”)?

Question

I have seen most cases developers use first string and after that variable used in .equal operation. What is the reason?

Answer 1

Because var can be null and var.equals("string") will throw NullPointerException (attempt to call of method on null). On the other hand, "string".equals(null) will just return false.