シャドーイング練習: 🚫 Java Deadlock Explained: Why Your Code is Stuck 😱 (Beginners Must Watch!) - 動画で英語スピーキングを学ぶ
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We have seen deadlock example.
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We have given the example of the lock.
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But we are going to read deadlock officially.
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I will give you a example of how the code looks.
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We will see deadlock doesn't work.
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We will see how it will resolve.
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First of all, what is formal definition?
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In multi-threading, deadlock is a situation where the threats are always blocked.
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And they depend on the other side.
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For example, A and B, A has a pen and a paper.
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A waits for B, when he gives a paper, then I start to write.
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B waits for A, when he gives a pen, then I start to write.
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Just, nothing is wrong.
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One is waiting for another.
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So, the work will not be wrong and wait for forever.
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So, this is a condition called deadlock.
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Formal, formal.
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Formal, when it comes to match, the deadlock is called.
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Mutual exclusion.
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Sir, our critical section is called, which should be locked.
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First thing is obvious.
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Then there will be a wait.
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Another thing is, Hold and wait.
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A thread holding at least one resource is waiting to acquire.
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Obviously.
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Third thing is no preemption.
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You can't remove pen or pencil.
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You can't remove paper.
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We haven't read this yet.
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It's circular wait.
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This is obvious.
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The obvious thing is, they divide in 4 parts.
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It's false.
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But obviously, if someone's mind is bad, then they can ask.
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Okay, sir.
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So, theory has happened.
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Sir, a real life example.
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I have given you a class pen and a class paper.
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What is written in pen?
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Write with pen and paper.
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It is a method.
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It is called paper.finishedWriting.
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Another class is class paper.
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It is called write with write with paper and pen.
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And then finish writing method.
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I am going to show you the functionality.
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What is written in the upper part?
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I will go in the upper part.
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I will make two threads.
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Task 1.
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The next thread is task 2.
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In the main thread, a pen and a paper and the threads are made.
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Then I will start.
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I am giving a high level overview.
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Thread 1 is using pen and is trying to use paper.
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Thread 2 is using paper and trying to use pen.
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And it's going infinitely.
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I will close it to forcefully.
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The condition is the same.
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Two threads have two people.
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One has pen and trying to use paper.
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The other one has B.
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The other one has paper and trying to use pen.
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The solution is not coming.
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This is deadlock.
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Now, look at the code.
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There are two methods, paper, and two threads.
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Task 1 and Task 2.
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We will create the object in that two objects.
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Pen and paper.
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Similarly with Task 2.
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When we create the object in Task 2, we will create the object in the constructor.
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Obviously, one pen will be and one paper.
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So, two people are.
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Thread 1 and Thread 2.
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There are two things.
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One pen and one paper.
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Thread 1 is written in the first one.
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One person has pen.
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Pen.Write with pen and paper.
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The other person has paper.
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Now we are going to pen and paper class.
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Pen has two methods.
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Write with pen and paper and finish writing.
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Paper has two methods.
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Write with paper and pen and finish writing.
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Pen has been written in thread 1.
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Synchronize is put.
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When a method is declared by synchronized keyword,
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this method will acquire the intrinsic lock of the object the method belongs to.
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Pen will acquire the method.
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Pen will acquire the method.
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And then, paper.finish writing.
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This method will need paper and pen,
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so it comes to paper and pen.
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and he is trying to run pen.finish writing.
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When will it run pen?
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When it has a pen lock.
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What do you mean?
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It depends on the other one.
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What is thread 1?
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It has a pen.
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And trying to use paper.
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Similarly thread 2 is using paper and trying to use pen.
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But nothing is happening.
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Then we close it.
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What is deadlock?
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If it has not been done, then see it again.
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I am saying it again.
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Now I need to resolve this, I need to resolve this, deadlock is not necessary.
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So what can I do?
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There are many strategies.
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What is common approach?
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Ensure that all the threats are consistent order to acquire locks.
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Consistent order means that multiple threats which are required to acquire locks and multiple resources,
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they should always acquire the resources in the same sequence.
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Class pen and paper Here is the lock acquired.
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What is the lock?
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The pen and paper are the same.
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We will do the same work.
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If we change the lock, then the result will be deadlock.
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Now, Task 1 is going to lock pen and paper.
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Task 2 is going to lock pen and pen.
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What do we do?
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We use the synchronized keyword.
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We want to lock and pen.
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We will say Task 2 is going to lock pen and pen.
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Then, paper can lock.
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This is the two things.
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I will put it here.
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It will make sure that thread 2 is going to lock pen.
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When you have pen lock, it's a good thing.
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But pen lock is a thread 1, no matter what you will do.
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And paper lock will come, because thread to run not.
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Because thread to run, you should have pen lock, then paper lock will acquire.
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So, understand how now.
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If we change ordering, consistent ordering,
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lock will acquire, we can resolve the deadlock.
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Okay?
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Now, keep the tension so much.
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Keep the tension so much.
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Sir, we have a small example which we have resolved.
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That's it.
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Keep the tension so much.
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Keep the tension so much.
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Okay, sir.
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この動画で話す練習をする理由
YouTubeで英語学習をするなら、実際の会話に近いスピーチが聞ける動画が最適です。この動画では、「デッドロック」という技術用語を使いながら、分かりやすく説明する様子が捉えられています。日常的な会話だけでなく、専門的な内容も含めたスピーキング力を養うことができます。また、話し手の口調やペースが自然であるため、英語シャドーイングの練習にも最適です。IELTS スピーキング対策にも役立つ、論理的な説明の仕方を学ぶことができます。
文脈の中の文法と表現
- 「We have seen deadlock example.」：現在完了形を使って過去の経験を述べています。「example」の前に「a」が抜けていますが、口語ではよくある省略形です。
- 「A thread holding at least one resource is waiting to acquire.」：現在分詞構文「holding...」で修飾語をつけ、文を簡潔にしています。「is waiting to acquire」で「～を獲得するのを待っている」という意味を表しています。
- 「What is written in the upper part?」：受動態を使って「上部に何が書かれているのか」と尋ねています。技術的な説明では受動態がよく使われるので、覚えておきましょう。
発音の注意点
英語の発音を良くするためには、以下のようなトラップに注意しましょう。「deadlock」の「ea」は「エ」ではなく「エッ」と短く発音します。「mutual」の「u」は「ミュー」ではなく「マュー」に近い音です。また、「preemption」の「tion」は「ション」ではなく「シャン」と発音するのが正しいです。これらの単語を繰り返しシャドーイングすることで、自然な発音を身につけることができます。
シャドーイングとは？英語上達に効果的な理由
シャドーイング（Shadowing）は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的：ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影（shadow）」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。