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

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

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

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

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

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

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

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

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

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.

See if you know how to use the predicate, consumer, function, and supplier interfaces.

Overloaded methods must be valid, and all ambiguities must be resolved.

Java control statements can be confusing to learn and use correctly.

The objective in this Java SE quiz is to understand how to use conditional operators.

You’re tasked with moving an application to JPMS. What’s the command line?

The consumer interface can be confusing, even for advanced coders.

Predicate interfaces can be complicated, so be careful when working out the results.

Can a lambda return a lambda?

The subtleties of using var in lambda expressions

Using var with two-dimensional arrays requires careful attention.