Java nangani kesalahan karo try/catch/finally, lan unikno mbedake panganan checked (kudu dinyatakake utawa ditangani) saka panganan unchecked (runtime, ora dipeksa). Kapaham bedane iki minangka tengah-tengahing panganan kesalahan Java.
Java nangani kesalahan karo try/catch/finally, lan unikno mbedake panganan checked (kudu dinyatakake utawa ditangani) saka panganan unchecked (runtime, ora dipeksa). Kapaham bedane iki minangka tengah-tengahing panganan kesalahan Java.
try {
FileReader f = new FileReader("file.txt"); // may throw IOException
// ... use it ...
} catch (FileNotFoundException e) {
System.out.println("not found: " + e.getMessage()); // specific first
} catch (IOException e) {
System.out.println("io error"); // broader after
} finally {
System.out.println("always runs — cleanup"); // runs no matter what
}
finally tansah dijalanaken (bebersihan), sanajan panganan dilebokake utawa return dumadi.
Throwable
├── Error — serious JVM problems (OutOfMemoryError) — don't catch
└── Exception
├── RuntimeException → UNCHECKED (not enforced by the compiler)
│ NullPointerException, IllegalArgumentException, IndexOutOfBounds...
└── (other Exceptions) → CHECKED (compiler enforces handling)
IOException, SQLException...
// MUST either catch it or declare `throws` — the compiler won't let you ignore it
public void readFile() throws IOException { // declare it
Files.readAllLines(Paths.get("file.txt")); // throws checked IOException
}
Panganan checked (IOException, SQLException) makili kahanan sing bisa dipulih, kaandele (file ilang, gagal jaringan). Compiler memaksa sampeyan nangani utawa dinyatakake — nggawe panganan gagal eksternal gamblang.
// NOT required to declare or catch — usually indicate PROGRAMMING BUGS
String s = null;
s.length(); // NullPointerException (unchecked)
int x = arr[10]; // ArrayIndexOutOfBoundsException (unchecked)
Integer.parseInt("abc"); // NumberFormatException (unchecked)
Panganan unchecked (subclass RuntimeException) biasane tandha kesalahan program — sira ngamandake bug tinimbang nangani ing sadurunge. Compiler ora memaksa panganan.
// resources implementing AutoCloseable are closed automatically
try (FileReader f = new FileReader("file.txt")) {
// use f
} // f.close() called automatically, even on exception — no finally needed
✓ Catch specific exceptions, not bare Exception
✓ Use try-with-resources for files/connections (auto-close)
✓ Don't swallow exceptions silently (empty catch blocks)
✓ Throw meaningful exceptions; include context in messages
✓ Custom exceptions extend Exception (checked) or RuntimeException (unchecked)
Panganan kesalahan sing kuat kudu diperlokake, lan bedane checked/unchecked Java minangka fitur (lan kapengin diperdebatake) sing perlu dikapaham kanthi jembar.
Panganan checked memaksa panganan gamblang gagal eksternal kaandele (I/O, DB) — ningkatake kapercayan nanging kadhang dikritik minangka ramet; panganan unchecked makili bug sing kudu didandani tinimbang ditangani.Ngerti hierarki, bisokna saben jinis, semantik try/catch/finally, lan try-with-resources modern kanggo bebersihan otomatis minangka dhasar kanggo nulis Java sing bener lan kapercayan — lan kanggo ngrumusake panganan dhewe kanthi bener.
Bedane membentuk cara API Java dirancang lan minangka ginem sing kerep ana ing wawancara lan ulasan kode.