Apa iku konstruktor lan destruktor?

Question

Accepted Answer

**Konstruktor** iku metode khusus sing dijalanake nalika obyek digawe, dienggo kanggo **nglembagani** kaadaane dadi kondisi awal sing sah. **Destruktor** (utawa finalizer) dijalanake nalika obyek ilang, dienggo kanggo **resiki** sumber daya.

## Konstruksi

```java
public class Connection {
    private final String host;
    public Connection(String host) {   // constructor
        if (host == null)              // enforce a valid object from birth
            throw new IllegalArgumentException("host required");
        this.host = host;              // initialize state
    }
}
```

Konstruktor sing apik njamin obyek **ora bakal katon ing kaadaan ora sah**.

## Resiki beda-beda miturut basa

```python
class FileWriter:
    def __init__(self, path):
        self.f = open(path, "w")       # acquire resource
    def close(self):
        self.f.close()                 # explicit cleanup
    def __enter__(self): return self
    def __exit__(self, *a): self.close()  # deterministic cleanup

with FileWriter("out.txt") as w:       # closed automatically at block end
    pass
```

| Basa | Mekanisme resiki |
|---|---|
| C++ | Destruktor `~T()`, dijalanake deterministik |
| Java/C# | GC + `finalize`/`Dispose` (non-deterministik; gunakake try-with-resources / `using`) |
| Python | `__del__` (timing ora terpercaya); pilih context manager |

## Cilaka

Padha basa karo garbage collection, **aja gumantung marang finalizer** kanggo ngeculake file, socket, utawa gembok — waktune ora ditemtokake. Gunakake eksplisit `close`/`Dispose`/context manager.

## Apa mundhak penting

Konstruktor iku jaminan sing saben obyek diwiwiti valid — papan paling apik kanggo maksa argumen kudu lan invariant.

Resiki penting amarga sumber daya kanteg (file handle, sambungan) bocor yen ora dilepas, lan gumantung ing GC kanggo mbikak ilang kadang-kadang, ilang susah di-debug.

Basa	Mekanisme resiki
C++	Destruktor `~T()`, dijalanake deterministik
Java/C#	GC + `finalize`/`Dispose` (non-deterministik; gunakake try-with-resources / `using`)
Python	`__del__` (timing ora terpercaya); pilih context manager