In this task we need terminal. I tryied wrote javac Solution.java. And I get 
Command 'javac' not found, but can be installed with:
sudo apt install openjdk-11-jdk-headless  # version 11.0.17+8-1ubuntu2~22.04, or
sudo apt install default-jdk              # version 2:1.11-72build2
sudo apt install openjdk-17-jdk-headless  # version 17.0.5+8-2ubuntu1~22.04
sudo apt install openjdk-18-jdk-headless  # version 18.0.2+9-2~22.04
sudo apt install openjdk-19-jdk-headless  # version 19.0.1+10-1ubuntu1~22.04
sudo apt install openjdk-8-jdk-headless   # version 8u352-ga-1~22.04
sudo apt install ecj                      # version 3.16.0-1
I wrote -> sudo apt install openjdk-19-jdk-headless # version 19.0.1+10-1ubuntu1~22.04 and answer for my 0 error program, when I wrote another time -> javac Solution.java -> is : Solution.java:16: error: cannot find symbol public static List<Person> allPeople = new ArrayList<>(); ^ symbol: class Person location: class Solution Solution.java:20: error: cannot find symbol allPeople.add(Person.createMale("Donald Chump", new Date())); // id=0 ^ symbol: variable Person location: class Solution Solution.java:21: error: cannot find symbol allPeople.add(Person.createMale("Larry Gates", new Date())); // id=1 ^ symbol: variable Person location: class Solution Solution.java:50: error: cannot find symbol for (Person p : allPeople) { ^ symbol: class Person location: class Solution 4 errors I don't know what's going on. I don't understand why I haven't java in intelliji :(