Language: Java

public class Main {
	public static void main(String[] args) {
		Map<Integer, Integer> heightsOfMountain = new HashMap<>();
		Scanner scanner = new Scanner(System.in);
		for (int i = 1; i <= 10; i++) {
			int height = scanner.nextInt();
			heightsOfMountain.put(i, height);
		}
		System.out.println(heightsOfMountain);

		Set<Entry<Integer, Integer>> set = heightsOfMountain.entrySet();
		List<Entry<Integer, Integer>> list = new ArrayList<Entry<Integer, Integer>>(set);
		Collections.sort(list, new Comparator<Map.Entry<Integer, Integer>>() {
			@Override
			public int compare(Entry<Integer, Integer> o1, Entry<Integer, Integer> o2) {
				// TODO Auto-generated method stub
				return (o2.getValue()).compareTo(o1.getValue());
			}
		});

		System.out.println("Height of the 1st mountain " + list.get(0).getValue());
		System.out.println("Height of the 2nd mountain " + list.get(1).getValue());
		System.out.println("Height of the 3rd mountain " + list.get(2).getValue());
	}
}

Compiler output:
Main.java:3: error: cannot find symbol
		Map<Integer, Integer> heightsOfMountain = new HashMap<>();
		^
  symbol:   class Map
  location: class Main
Main.java:3: error: cannot find symbol
		Map<Integer, Integer> heightsOfMountain = new HashMap<>();
		                                              ^
  symbol:   class HashMap
  location: class Main
Main.java:4: error: cannot find symbol
		Scanner scanner = new Scanner(System.in);
		^
  symbol:   class Scanner
  location: class Main
Main.java:4: error: cannot find symbol
		Scanner scanner = new Scanner(System.in);
		                      ^
  symbol:   class Scanner
  location: class Main
Main.java:11: error: cannot find symbol
		Set<Entry<Integer, Integer>> set = heightsOfMountain.entrySet();
		^
  symbol:   class Set
  location: class Main
Main.java:11: error: cannot find symbol
		Set<Entry<Integer, Integer>> set = heightsOfMountain.entrySet();
		    ^
  symbol:   class Entry
  location: class Main
Main.java:12: error: cannot find symbol
		List<Entry<Integer, Integer>> list = new ArrayList<Entry<Integer, Integer>>(set);
		^
  symbol:   class List
  location: class Main
Main.java:12: error: cannot find symbol
		List<Entry<Integer, Integer>> list = new ArrayList<Entry<Integer, Integer>>(set);
		     ^
  symbol:   class Entry
  location: class Main
Main.java:12: error: cannot find symbol
		List<Entry<Integer, Integer>> list = new ArrayList<Entry<Integer, Integer>>(set);
		                                         ^
  symbol:   class ArrayList
  location: class Main
Main.java:12: error: cannot find symbol
		List<Entry<Integer, Integer>> list = new ArrayList<Entry<Integer, Integer>>(set);
		                                                   ^
  symbol:   class Entry
  location: class Main
Main.java:13: error: cannot find symbol
		Collections.sort(list, new Comparator<Map.Entry<Integer, Integer>>() {
		                           ^
  symbol:   class Comparator
  location: class Main
Main.java:13: error: package Map does not exist
		Collections.sort(list, new Comparator<Map.Entry<Integer, Integer>>() {
		                                         ^
Main.java:15: error: cannot find symbol
			public int compare(Entry<Integer, Integer> o1, Entry<Integer, Integer> o2) {
			                   ^
  symbol: class Entry
Main.java:15: error: cannot find symbol
			public int compare(Entry<Integer, Integer> o1, Entry<Integer, Integer> o2) {
			                                               ^
  symbol: class Entry
Main.java:14: error: method does not override or implement a method from a supertype
			@Override
			^
Main.java:13: error: cannot find symbol
		Collections.sort(list, new Comparator<Map.Entry<Integer, Integer>>() {
		^
  symbol:   variable Collections
  location: class Main
16 errors