Piye carane array bisa makarya ing Java?

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**Array** yaiku koleksi ukuran tetap lan terukur saka elemen saka **jenis sing sama**, disimpen kanthi bersebelahan ing memori. Array minangka dasar, nanging ukurane sing tetap bidhal yen asring luwih seneng `ArrayList` kanggo koleksi dinamis. ## Ndeklarasiaken lan nggawe array ```java int[] nums = new int[5]; // size 5, default-initialized to 0 int[] nums2 = {1, 2, 3, 4, 5}; // declare + initialize with values String[] names = new String[3]; // objects default to null nums[0] = 10; // set by index (0-based) int x = nums[0]; // get by index nums.length; // 5 — the size (a field, NOT a method!) ``` Array nduweni **ukuran tetap** sing ditetapake nalika digawe — sampeyan ora bisa nambah utawa ngurangi ukurane. Elemen standar kanggo nilai-nilai sing cocok karo tipe (`0`, `0.0`, `false`, `null`). ## Jebakan umum: length yaiku werna ```java nums.length; // ✅ array — a field (no parentheses) str.length(); // ✅ String — a method (parentheses) list.size(); // ✅ collection — a method ``` Array `length` yaiku werna; String `length()` lan koleksi `size()` yaiku metode — titik kebingungan sing asring. ## Pambatasan mriksa ```java int[] arr = {1, 2, 3}; arr[5]; // ❌ ArrayIndexOutOfBoundsException — Java checks bounds at runtime ``` Java nglontar pangecualian kanggo akses sing diluar wates (ora kaya C, sing nduweni perilaku undefined) — luwih aman, nanging sampeyan kudu tetep ing `0` nganti `length-1`. ## Iterasi ```java // enhanced for-each (when you don't need the index) for (int n : nums) { System.out.println(n); } // traditional for (when you need the index) for (int i = 0; i < nums.length; i++) { nums[i] *= 2; } ``` ## Array multidimensional ```java int[][] matrix = {{1, 2}, {3, 4}}; // array of arrays matrix[0][1]; // 2 ``` ## Array lawan ArrayList — kapan nganggo apa ```text Array → fixed size, slightly faster, can hold primitives directly (int[]) ArrayList → DYNAMIC size (grow/shrink), rich methods (add/remove/contains), but holds objects only (Integer, not int) ``` ```java List list = new ArrayList<>(); list.add(1); // grows dynamically — no fixed size list.remove(0); ``` Gunakake array biasa kanggo ukuran tetap, data sensitif kinerja, utawa primitif; gunakake `ArrayList` nalika ukuran owah utawa butuh operasi nyeneng. ## Apa dadi penting Array yaiku struktur data mendasar ing Java — cepet, hemat memori, panyimpen bersebelahan sing digunakake langsung lan minangka punggawa kanggo koleksi akeh (`ArrayList` mbungkus array). Ngerteni sifate ukuran tetap, indheksasi basis-0, mriksa wates runtime, `length` werna (lawan metode) jebakan, lan utamane **kapan nganggo array lawan ArrayList** (tetap/primitif/cepet lawan dinamis/seneng) minangka penting. Array katon terus-terusan ing algoritma lan kode kritis kinerja, dene ngerti watas-watase (ora ada ngubah ukuran) karanganake apa koleksi dinamis ana lan biasane cocok kanggo panggunaan umum.