Best way to handle nulls in Java
The Best Feeling at starting stage of my development is seeing the Output without ‘NullpointerException‘, but its very difficult. So handling null values is more important in Coding to get a clear and satisfied Result. Let see how to handle nulls in Java
Optional Class
we have so many ways to compare NULL string, I.e Optional in Java 8 as below:
import java.util.Optional;
String str= null; Optional<String> str2 = Optional.ofNullable(str);
then use isPresent() , it will return false if str2 contains NULL otherwise true
if(str2.isPresent()) { //If No NULL else { //If NULL }
The above example is little complicated, but Optional is a container object used to contain not-null objects. Optional object is used to represent null with absent value. This class has various utility methods to facilitate code to handle values as ‘available’ or ‘not available’ instead of checking null values.
Reference
Simplest Way
Simply you can check the String variable is null, use the following statement.
if(myString==null)//It's good if (Optional.ofNullable(myString).isPresent()) // Complicated if (Objects.nonNull(myString)) // better, but still Complicated
null
is a keyword in Java,"null"
is just a string of text.
Deference Null
If a variable is null, you cannot deference it.
That means you can not invoke methods on it.
So… The following if statement will throw a NullPointerException every time the first clause is true:
if (myString == null && myString.length() == 0)
In other words: if myString
is null, you CANNOT invoke the length method on myString
.
Happy Learning 🙂