"Variable not initialized"

This is a class that I made to test my if-else statement for calculating withholding tax for gross pay. The error I get is this:
error: variable tax might not have been initialized
System.out.println("Withholding Tax = " + tax);

I initialized the variable tax and covered all of the possible values for gross in the if-else statements. So what am I doing wrong?

Code :

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import java.util.Scanner;
class apples
{
	public static void main(String args[])
	{
		Scanner input = new Scanner(System.in);
		double gross = input.nextDouble();
		double tax;
 
		if (0 <= gross && gross <= 300.00)
		{
			tax = 0.10;
		}
		else if (300.01 <= gross && gross <= 400.00)
		{
			tax = 0.12;
		}
		else if (400.01 <= gross && gross <= 500.00)
		{
			tax = 0.15;
		}
		else if (gross >= 500.01)
		{
			tax = 0.20;
		}
		else
		{
			System.out.println("ERROR! Gross pay is less than zero");
		}
 
		System.out.println("Withholding Tax = " + tax);
	}
}

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Hello davis220!
You have not initialized tax, you have declared it

Code java:

---

double tax;

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You should just give it an initial value (0 is very common for a double).