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Interesting facts about null in Java
There are many facts associated with null in Java. We will discuss a few of them here with examples −
The default value of any reference variable in Java is always null.
Example
public class Demo{
private static Object my_obj;
public static void main(String args[]){
System.out.println("The default value of object my_obj is : " + my_obj);
}
}Output
The default value of object my_obj is : null
A class named Demo defines a static object and the main function that shows the default value of this pre-defined object.
The not equal to (!=) and comparison (==) operators can be used with the null keyword.
Example
public class Demo{
public static void main(String args[]){
System.out.println("The value of null == null is : ");
System.out.println(null==null);
System.out.println("The value of null != null is : ");
System.out.println(null!=null);
}
}Output
The value of null == null is : true The value of null != null is : false
A class named Demo contains the main function that checks to see the output when the null values are compared using ‘==’ operator and when they are checked using the ‘!=’ operator.
The keyword null is case-sensitive
Example
public class Demo{
public static void main (String[] args) throws java.lang.Exception{
Object my_obj_1 = NULL;
Object my_obj_2 = null;
}
}Output
/Demo.java:5: error: cannot find symbol Object my_obj_1 = NULL; ^ symbol: variable NULL location: class Demo 1 error
Updated on: 04-Jul-2020
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