Quiz yourself: Understanding valid annotation declarations

By Simon Roberts and Mikalai Zaikin

Explore the allowed method return types to see where the code succeeds… or fails.

Quiz yourself: Use primitives such as the % operator

By Simon Roberts and Mikalai Zaikin

Test your knowledge of Java’s primitive operators.

Quiz yourself: Security threats and malicious code modifications

By Simon Roberts and Mikalai Zaikin

Here’s what happens when good code meets bad people.

Quiz yourself: Say “hello” to the 1Z0-819 Java SE 11 certification exam

By Simon Roberts and Mikalai Zaikin

You now need only pass a single exam to become a certified Java SE 11 Developer.

Quiz yourself: Correctly apply the static keyword to methods and fields

By Simon Roberts and Mikalai Zaikin

Test your knowledge of static fields in Java.

Quiz yourself: Create and extend abstract classes

By Simon Roberts and Mikalai Zaikin

Test your knowledge of abstract classes and their methods.

Quiz yourself: Read and write objects by using serialization

By Simon Roberts and Mikalai Zaikin

Test your knowledge of the java.io.Serializable interface.

Quiz yourself: Apply encapsulation principles to a class

By Simon Roberts and Mikalai Zaikin

Test your knowledge of a key object-oriented programming concept.

Quiz yourself: Use the Files class to copy or move files and directories

By Simon Roberts and Mikalai Zaikin

Test your knowledge of the java.nio.file.Files class.

Quiz yourself: Create worker threads using Runnable and Callable (advanced)

By Simon Roberts and Mikalai Zaikin

Test your knowledge of what happens when you use the ExecutorService.

Quiz yourself: Define the structure of a Java class (intermediate)

By Simon Roberts and Mikalai Zaikin

Test your knowledge of Java classes, such as their valid names, the use of variables inside a method, and the number of import statements.

Quiz yourself: Declare and use List and ArrayList instances (intermediate)

By Simon Roberts and Mikalai Zaikin

Work with lists while avoiding unpleasant UnsupportedOperationException errors.

Quiz yourself: Search stream data using the findFirst, findAny, and anyMatch methods (advanced)

By Simon Roberts and Mikalai Zaikin

Streams are complicated. With the right approach, they can be very efficient too.

Quiz yourself: Describe the modular SDK (intermediate)

By Simon Roberts and Mikalai Zaikin

Know which command-line utilities are mandatory for distributing applications with a custom JRE.

Quiz yourself: Use the Optional class (advanced)

By Simon Roberts and Mikalai Zaikin

Do you know how to use Optional? Find out in the latest by Simon and Mikalai.

Quiz yourself: Use PreparedStatement to perform database CRUD operations (intermediate)

By Simon Roberts and Mikalai Zaikin

PreparedStatement sends SQL to a database. Let’s see how it works.

Quiz yourself: Declaring and accessing modules (intermediate)

By Simon Roberts and Mikalai Zaikin

This intermediate-level Java SE 11 certification quiz tests your ability to declare modules and enable access between modules.

Quiz yourself: Applying access modifiers to Java classes (intermediate)

By Simon Roberts and Mikalai Zaikin

This Java certification quiz investigates the meaning of default accessibility and how it influences classes in different packages.

Quiz yourself: Methods that throw an exception (intermediate)

By Simon Roberts and Mikalai Zaikin

Understanding the checked exception mechanism requires that you understand how to declare a method that throws a checked exception, and how that differs from a method that either does not throw any exceptions or throws only unchecked ones.

Quiz yourself: Refactoring with the core functional interfaces (intermediate)

By Simon Roberts and Mikalai Zaikin

See if you know how to improve code by refactoring.