Java - Switch Statement

Question

public class Program
{
public static void main(String[] args) {
int x = 4;
int y = 0;
switch(--x){
case 3:
y+=x;
case 4:
y+=x;
case 2:
y+=x;
default:
y++;
break;
}
System.out.println(y);
}
}

The output comes to 10. My calculation was 4. X value decrements from 4 to 3 and go to the switch value 3 and x value of 3 is added to y, and y value of 3 increments by one through default. I don't see how it arrives at 10. Please help.

Answer 1

y=3 (after case 3)
y=6 (after case 4)
y=9 (after case 2)
y=10 (after default case)

"Not every case needs to contain a break. If no break appears, the flow of control will fall through to subsequent cases until a break is reached." This is known as fall through, you can read the same in java switch lesson using below link:
https://www.sololearn.com/learn/Java/2145/?ref=app

Answer 2

switch is first check for the matching case, if found, then executes corresponding statements.
If there is no break falthrough happens until a break encounters..
So there is no break after a case then a falthrough happens that means it's executes remaining proceeding cases also including default also if no break statement found.
So Here,
Case 3 matched
y+=x;
y=3
y+=x;
y=6;
y+=x;
y=9;
y++;
y=10;
break; //found so comes out switch.
So answer is 10