The only guide you’ll need on concurrency & multithreading for senior engineers. Pressure test your skills with real-world practice problems from top companies.

Concurrency in Java is one of the most complex and advanced topics brought up during senior engineering interviews. Knowledge of concurrency and multithreading can put interviewees at a considerable advantage. This course lays the foundations of advanced concurrency and multithreading and explains concepts such as Monitors and Deferred Callbacks in depth. It also builds simple and complete solutions to popular concurrency problems that can be asked about in interviews like the Reader-Writer Problem and the Dining Philosopher Problem. While prior knowledge of concurrency is not required to follow through with this course, familiarity with the very basics of concurrency would be helpful.

Java Multithreading for Senior Engineering Interviews

<div class="card">
   # Question # 1
    <div class="qtn">
        <p>What is the <code class="clazz">synchronized</code> keyword?</p>
    </div>
    <div class="ans">
        <p>Java provides a built-in mechanism to provide atomicity called the <code class="clazz">synchronized</code> block. A synchronized method is a shorthand for a synchronized block that spans an entire method body and whose lock is the object on which the method is being invoked.</p>
<p>A synchronized block consists of a reference to an object that serves as the lock and a block of code that will be guarded by the lock.</p>
<p>Synchronized blocks guarded by the same lock will execute one at a time. These blocks can be thought of as being executed atomically. Locks provide serialized access to the code paths they guard.</p>
<p>Below is an example of a class with a synchronized method.</p>

```java
class ContactBook {

    Collection<String> contacts = new ArrayList<>();

    synchronized void addName(String name) {
        contacts.add(name);
    }
}
```
<p>Note the synchronized method above is equivalent to the following rewrite:</p>

```java
    void addName(String name) {
        synchronized(this) {
            contacts.add(name);
        }
    }
```

</div>
</div>


<div>
   # Question # 1
    <div>
        <p>What is the <code>synchronized</code> keyword?</p>
    </div>
    <div>
        <p>Java provides a built-in mechanism to provide atomicity called the <code>synchronized</code> block. A synchronized method is a shorthand for a synchronized block that spans an entire method body and whose lock is the object on which the method is being invoked.</p>
<p>A synchronized block consists of a reference to an object that serves as the lock and a block of code that will be guarded by the lock.</p>
<p>Synchronized blocks guarded by the same lock will execute one at a time. These blocks can be thought of as being executed atomically. Locks provide serialized access to the code paths they guard.</p>
<p>Below is an example of a class with a synchronized method.</p>

```java
class ContactBook {

    Collection<String> contacts = new ArrayList<>();

    synchronized void addName(String name) {
        contacts.add(name);
    }
}
```
<p>Note the synchronized method above is equivalent to the following rewrite:</p>

```java
    void addName(String name) {
        synchronized(this) {
            contacts.add(name);
        }
    }
```

</div>
</div>


The Basics

Multithreading in Java

Java's Memory Model

Interview Practice Problems

Bonus Questions

Beyond the Interview

Java Concurrency Reference

Revision & Quizzes

Quiz 4

Question # 1