import

// ── Import statement syntax: ─────────────────────────────────────────
package com.example.service;

// Single-type imports — explicit, preferred:
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

// Wildcard import — imports all types from java.io:
import java.io.*;

public class Example {
    // Can use ArrayList, HashMap, List, Map, BufferedReader, etc. by simple name
    private List<String> names = new ArrayList<>();
    private Map<String, Integer> scores = new HashMap<>();
}

// ── Without import — fully qualified names required: ──────────────────
public class NoImports {
    private java.util.List<String> names = new java.util.ArrayList<>();
    private java.util.Map<String, Integer> scores = new java.util.HashMap<>();

    public void readFile() throws java.io.IOException {
        java.io.BufferedReader br =
            new java.io.BufferedReader(new java.io.FileReader("data.txt"));
    }
}

// ── Ambiguity — two packages define a class with the same name: ────────
import java.util.Date;
import java.sql.Date;   // COMPILE ERROR — java.util.Date already imported

// Resolution: import one, use fully qualified for the other:
import java.util.Date;   // java.util.Date available as 'Date'

public class DateExample {
    Date utilDate = new Date();                   // java.util.Date
    java.sql.Date sqlDate = new java.sql.Date(0); // fully qualified
}

// ── What wildcard * does NOT include: ─────────────────────────────────
import java.util.*;     // imports: ArrayList, HashMap, List, Set, etc.
                        // does NOT import: java.util.concurrent.ConcurrentHashMap
                        // does NOT import: java.util.stream.Collectors
                        // sub-packages are SEPARATE packages — not included

// ── Single-type imports — explicit, recommended: ─────────────────────
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;
import java.util.stream.Stream;

// Reading the imports, you immediately know this file uses:
// ArrayList, Collections, HashMap, List, Map, Optional, and streams.

// ── Wildcard import — terse but opaque: ───────────────────────────────
import java.util.*;
import java.util.stream.*;

// You cannot tell from imports alone which classes are actually used.
// Could be ArrayList + List, or could be LinkedList + Queue + Deque.

// ── java.lang is always implicitly imported: ──────────────────────────
// No import needed for:
String    s  = "Hello";          // java.lang.String
Integer   i  = 42;               // java.lang.Integer
System.out.println("Hi");        // java.lang.System
Math.sqrt(16);                   // java.lang.Math
Thread.sleep(100);               // java.lang.Thread

// ── IDE convention — organised import groups: ─────────────────────────
//
// Most projects organise imports in groups, each separated by a blank line:
// 1. java.* standard library
// 2. javax.* and jakarta.* extensions
// 3. Third-party libraries (org.springframework, com.fasterxml, etc.)
// 4. Project-internal packages

import java.io.IOException;
import java.util.List;

import jakarta.persistence.Entity;
import jakarta.persistence.Id;

import org.springframework.stereotype.Service;

import com.example.model.Order;
import com.example.repository.OrderRepository;