Lambdas are essentially expressions that define a class and instantiate an object from that class. Do you know how to use them?
These three classes are powerful—but they can be tricky when combined.
Sometimes a slash is not a slash, as this quiz explains.
Explore the allowed method return types to see where the code succeeds… or fails.
Do you know how to protect your system’s /etc/passwd file?
Test your knowledge of Java’s primitive operators.
Here’s what happens when good code meets bad people.
Test your knowledge of Java—and your debugging skills too.
You now need only pass a single exam to become a certified Java SE 11 Developer.
Test your knowledge of static fields in Java.
Test your knowledge of abstract classes and their methods.
Test your knowledge of the java.io.Serializable interface.
Test your knowledge of a key object-oriented programming concept.
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.
Work with lists while avoiding unpleasant UnsupportedOperationException errors.
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.