Inheritance is a fundamental concept in object-oriented programming languages like Java. It allows a class to inherit the properties and methods of another class, also known as the superclass or parent class. The class that does the inheriting is known as the subclass or the child class.

Inheritance is an important mechanism for creating new classes that extend or modify the functionality of existing classes. It enables a developer to reuse code and avoid duplication, which in turn saves time and reduces errors.

When a subclass is created, it automatically has access to all of the public and protected methods and fields of its parent class. This means that the code in the parent class can be reused without having to write new code in the subclass. Additionally, the subclass can also have its own unique methods and fields, which can be used to customize the inherited behavior.

Inheritance also allows for polymorphism, which means that a subclass object can be treated as an object of its parent class. This allows for greater flexibility and abstraction in programming.

Overall, inheritance is a powerful and flexible feature of Java that makes it easier to write and manage complex programs. By reusing code, reducing duplication, and enabling polymorphism, inheritance helps to improve the structure, readability, and maintainability of Java code.