Java null reserved word

In Java, null is a reserved word for literal values. It seems like a keyword, but actually, it is a literal similar to true and false.

Points to remember

It is case-sensitive.
It is a value of the reference variable.
The access to a null reference generates a NullPointerException.
It is not allowed to pass null as a value to call the methods that contain any primitive data type.

Examples of Java null reserved word

Example 1

Let's see a simple example to display the default value of the reference variable.

public class NullExample1 {
	static NullExample1 obj;
	public static void main(String[] args) {
		
		System.out.println(obj);
	}
	
}

Output:

null

Example 2

Let's see an example to determine whether we can pass null to object reference variable.

public class NullExample2 {

	public static void main(String[] args) {
		NullExample2 obj = null;
		System.out.println(obj);
	}
	
}

Output:

null

Example 3

Let's see an example to display the default value of String.

public class NullExample3 {
	
String str;
	public static void main(String[] args) {
		NullExample3 obj=new NullExample3();
		System.out.println(obj.str);
	}
	
}
</pre></div>
<p><strong>Output:</strong></p>
<div class="codeblock3"><pre>
null
</pre></div>
<h2 class="h3">Example 4</h2>
<p>Let's see an example to return null from a method.</p>
<div class="codeblock"><textarea name="code" class="java">
public class NullExample4 {
	String display()
	{
		return null;
	}
	public static void main(String[] args) {
	NullExample4 obj=new NullExample4();
		System.out.println(obj.display());
	}
}

Output:

null

Example 5

Let's see an example to provide null to the String variable.

public class NullExample5 {
	static String str=null;
	public static void main(String[] args) {
	if(str==null)
	{
		System.out.println("value is null");
	}
	else
	{
		System.out.println("value is not null");
	}
}
}

Output: