Why runtime exception thrown is this code

[Divyya Joshi]

The following code throws RuntimeException and i am not able to figure out the cause of it.
kindly help me.
Here's the code

class ClassA
{
	public void methodA()
	{
		ClassB classB=new ClassB();
		classB.getValue();
	}
}
class ClassB
{
	public ClassC classC;
	public String getValue()
	{
		return classC.getValue();
	}
}
public class ClassC
{
	public String value;
	public String getValue()
	{
		value="Clara";
		return value;
	}
	public static void main(String s1[])
	{
		ClassA classA=new ClassA();
		classA.methodA();
	
	}
}

[John Stark]

You do

return classC.getValue(); 

but classC was not initialized and has therefore the default value null. This gives a NullPointerException. You have to create a ClassC object at some point.

John

[Meherdad Bomanbehram]

Hi Divyya,
In ClassB you have declared but not instantiated ClassC .To refer to ClassC you have to either create an instance of the class or make the ClassC method static .If you choose to make the getValue() method static you will require to make the String variable value static too .

[Divyya Joshi]

Thanks John and MeherDad