How to retrieve ID elements from ArrayList

Could you help me to retrieve one of the ArrayList elements? Precondition is below.

Product class has three properties(productID, product name, price), so throw the below values in the constructor and create an object.

Product chocolate = new Product("5", "chocolate", 12);

Department class has two properties(department ID, department name), so throw the below values in the constructor and create an object.
Department class also has "addProduct" method, so add the above chocolate object in the grocery department.

Department groceries= new Department("2", "groceries");
groceries.addProduct(chocolate);

Directory class has an ArrayList, so added groceries department in the ArrayList using "addDepartemnt" method.

Directory directory = new Directory();
directory.addDepartment(groceries);

Suppose there are multiple products. Is there any way to retrieve "productID" from the directory ArrayList? I am going to loop the directory ArrayList and compare the IDs and user input ID, and it it's mactched, i want to retrieve all the product information (productID, product name, price).

public class Department implements Catalog {
private ArrayList<Catalog> subCatalogList = new ArrayList<Catalog>();
private String departmentId;
private String departmentName;
public Department(String departmentId, String departmentName){
this.departmentName = departmentName;
this.departmentId = departmentId;
}
public void addProduct(Catalog catalog){
subCatalogList.add(catalog);
}
public class Directory implements Catalog {
private ArrayList<Catalog> catalogDirectory = new ArrayList<Catalog>();
public void addDepartment(Catalog department){
catalogDirectory.add(department);
}
public class Product implements Catalog {
private String prodId;
private String prodName;
private double price;
public Product(String prodId, String prodName, double price){
this.prodId = prodId;
this.prodName = prodName;
this.price = price;
}

You can achieve his using Java streams, for example for a given productID and a given directory:

Product productToFind = (Product) directory.getCatalogDirectory ().stream()
.flatMap( department -> ((Department) department).getSubCatalogList().stream())
.filter( product -> ((Product)product).getProdId().equals(productID)).findFirst().get();

First, you gather all the products from a directory in one list using flatMap, and then you filter on it using the given productID.

EDIT:

Don't forget to add getters to your classes like bellow:

public class Department implements Catalog {
private ArrayList<Catalog> subCatalogList = new ArrayList<Catalog>();
private String departmentId;
private String departmentName;
public Department(String departmentId, String departmentName){
this.departmentName = departmentName;
this.departmentId = departmentId;
}
public void addProduct(Catalog catalog){
subCatalogList.add(catalog);
}
public ArrayList<Catalog> getSubCatalogList(){
return this.subCatalogList;
}
}
public class Directory implements Catalog {
private ArrayList<Catalog> catalogDirectory = new ArrayList<Catalog>();
public void addDepartment(Catalog department){
catalogDirectory.add(department);
}
public ArrayList<Catalog> getCatalogDirectory (){
return this.catalogDirectory ;
}
}
public class Product implements Catalog {
private String prodId;
private String prodName;
private double price;
public Product(String prodId, String prodName, double price){
this.prodId = prodId;
this.prodName = prodName;
this.price = price;
}
public String getProdId (){
return this.prodId;
}
} 

Test case:

@Test
public void test(){
Directory directory=new Directory();
Department dep =new Department("department1", "departmentName");
dep.subCatalogList = new ArrayList<>(Arrays.asList(new Product("idtofind", "hello name", 32)));
directory.catalogDirectory = new ArrayList<>(Arrays.asList(dep));
String productID="idtofind";
Product productToFind = (Product) directory.getCatalogDirectory ().stream()
.flatMap(department -> ((Department) department).getSubCatalogList().stream())
.filter(product -> ((Product)product).getProdId().equals(productID)).findFirst().get();
System.out.println(productToFind.prodName);
}