After introducing default method in Java 8, interfaces and abstract class seems to look same. However, they are actually different even in Java 8. The purpose of these two is still different. The main purpose of introducing default method is to introduce new features but maintaining backward compatibility. If you wish to add a method…

When a class implements two interfaces, each having default methods with same signature, it results in compile time error. To understand this with an example, we have created two interfaces: Left and Right. Class Test implements these two interface. On compilation, above code will result in following error: The reason for above error is that…

1. Introduction Before Java 8, interfaces could have only abstract methods. Java 8 has introduced default method which allows interfaces to have methods with implementation. default methods are declared with default keyword at the beginning of the method signature. 2. Need for default methods in Java interface Consider a requirement when you want to add…

As per Java 8 Language Specification: Any local variable, formal parameter, or exception parameter used but not declared in a lambda expression must either be declared final or be effectively final (§4.12.4), or a compile-time error occurs where the use is attempted. A variable which is not declared as final but whose value is never…

Following are the differences between anonymous inner class and lambda expression: In the following code, ‘this’ refers to the current inner class object. So, when we print this.score, the output is 100. In the following code, ‘this’ refers to enclosing class object . So, when we print this.score, the output is 0.

Differences between JAR file and module can be summarized in following points: JAR Module JAR stands for Java Archive and is a file format based on the ZIP file format. It is used for aggregating many files and associated metadata and resources(text, images etc) into one file to distribute as a library or application software.…

We’ll see in this tutorial, why JPMS was needed and what problems did JPMS solved. Lack of strong encapsulation Encapsulation can be achieved by using a combination of packages and access modifiers (such as private, protected, or public). When you make a class public, then it is public for everyone. There is no way to…

1. Introduction Java 9 introduced a new module system that makes modularization of applications easier. Java 9 modularity is built on top of the abstractions Java already has for encapsulations. Introduction of modules in Java 9 was a very big change as it resulted changes in JVM, the standard libraries and in the Java language…