switch, break & continue
switch replaces multiple if-else checks when you're comparing one variable against several fixed values — a break after each case is essential, otherwise the next case runs too (fall-through).
break stops a loop immediately. continue skips the current iteration and moves to the next one.
switch (day) {
case 1: System.out.println("Mon"); break;
case 2: System.out.println("Tue"); break;
default: System.out.println("Other");
}Purana switch fall-through ke saath break maangta hai — agar break bhool gaye, control agle case mein bhi "gir" (fall-through) jaata hai, chahe wo match na kare. Ye ek bahut common bug source raha hai purane Java code mein.
Java 14+ mein naya "arrow syntax" (case X -> ...) aaya jo automatically break kar deta hai (fall-through nahi hota — Java designers ne suna developers ki shikayatein!), aur yield keyword se switch expression se seedha value bhi return kar sakte ho — code chhota aur safer ho jaata hai.
| Traditional switch | Modern switch (14+) | |
|---|---|---|
| Fall-through | Haan (break zaroori) | Nahi (automatic) |
| Value return kar sakta hai? | Nahi (statement hai) | Haan (expression hai, yield se) |
| Multiple values ek case mein | case 1: case 2: | case 1, 2 -> |
// Modern style (Java 14+)
String dayType = switch (day) {
case 1, 7 -> "Weekend";
case 2, 3, 4, 5, 6 -> "Weekday";
default -> "Invalid";
};Java 7+ se switch String par bhi kaam karta hai (pehle sirf int/char/byte/short/enum par chalta tha) — internally ye hashCode() use karke implement hota hai. Enum ke saath switch bahut clean rehta hai kyunki saare possible cases pehle se fixed hote hain, aur IDE tumhe warn kar sakta hai agar koi case miss ho gaya.
Jab nested loops ho aur tumhe seedha outer loop se break/continue karna ho (sirf inner se nahi), tab "label" use karte ho — outer loop ke pehle ek naam de do (jaise outer:), aur break outer; likho. Bina label ke, break sirf sabse nazdeeki (innermost) loop ko todta hai.
outer:
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
if (j == 1) continue outer; // seedha outer loop ki agli iteration
System.out.println(i + "," + j);
}
}