How to check if my string is equal to null?
if (myString != null && !myString.isEmpty()) { // doSomething}As further comment, you should be aware of this term in the equals contract:
From Object.equals(Object):
For any non-null reference value
x,x.equals(null)shouldreturn false.
The way to compare with null is to use x == null and x != null.
Moreover, x.field and x.method() throws NullPointerException if x == null.
If myString is null, then calling myString.equals(null) or myString.equals("") will fail with a NullPointerException. You cannot call any instance methods on a null variable.
Check for null first like this:
if (myString != null && !myString.equals("")) { //do something}This makes use of short-circuit evaluation to not attempt the .equals if myString fails the null check.
Apache commons StringUtils.isNotEmpty is the best way to go.