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You've reached Level 37

"Hi, Amigo!" "Hi, Bilaabo!" "Our topic today won't merely be interesting — it will be downright epic." "Today I'm going to you what design patterns are." "Cool! I've heard a lot about them. I can't wait!" "Experienced programmers have to write a lot of classes. But the most difficult part of this job is deciding which classes to create and how to divide the work among them ..."

"Hello, friend!" "Hi, Bilaabo!" "We still have some time left, so I'll tell you about three more patterns." "Three more? How many are there in all?" "There are currently dozens of popular patterns, but the number of «successful solutions» is unlimited." "I see. So I have to learn several dozen patterns? ..."

"Hi, Amigo!" "Hi, Ellie!" "Today I want to tell you about iterators." "Iterators were invented practically at the same time as collections. The main purpose of collections is to store elements, and the main purpose of an iterator is to retrieve these elements one by one." "What's so difficult about getting a set of elements?" "First, the elements in some collections, such as Set, don't have ..."

"Hi, buddy. Here's an interesting task for you." "Wait, I'm getting a call" "Hello? Uh-huh... Yes... Factory... What about this factory??? Hello? Hello?" "Amigo, the captain called and said something about some factory and a secret agent. You're my friend, right? Go to this Agent IntelliJ IDEA and find out what's up with the factory. But, shh! Don't tell anyone." "Yes, I know the secret agent ..."

"And at long last, I'll tell you about Map." "Map, as you know, stores a set of key-value pairs. The keys must be unique, but the values can be anything. If you add a key-value pair to a Map, and the collection already contains the key, then the old value will be replaced with the new one. In other words, the key acts like a special index that can be any object. ..."

"Hi, Amigo!" "How was your morning lesson?" "Well, it was decent. I'll tell you about it." "Bilaabo gave me a bunch of design patterns, and Ellie showed me a whole bunch of collections. Not an easy day after all." "Don't you worry — I won't burden you with very much." "I want to tell you about the two utility classes that you've already encountered." "The Arrays and Collections classes ..."

"Amigo, I'm now only going to give you one task — but it's a very cool task! You've never done one like this before. It represents the pinnacle of skill! Now where is it... uh ... hmm... Anyway, go and do the tasks that you haven't done yet. Rest up and come again. I'll find it for you ..."

"Here I am." "I've been waiting for you here for a long time." "I hope so. Let's carry on, then." "I'm going to introduce you to present you a super-duper full-featured utility class for collections." "I'm already shaking all over with excitement." "Great. Then let's get started. Here are the methods of the Collections class ..."

"Hi, Amigo. Here's a useful task." "I remembered! Here's the task I promised you last time. Do you know what a SET is?" "I've know for a long time. And Rishi just told me about Collections utility class." "SET stands for Super Extreme Task. What did Rishi tell you about it?" "Uh, he told me about something else... about useful methods for collections." "About something else?? Okay, go check the task conditions ..."

"Hi, Amigo!" "Let's continue our lessons on how to google." "Here are some exercises ..."