What is runtime class in Java?

At the core of the Java runtime environment are the Java virtual machine, the Java interpreter, and the host operating system . The oval labelled Runtime in the diagram represents the current runtime environment and is an instance of the Runtime. class.

Predefined Classes in Java. The library of predefined class in Java is called Java class library or application programming interface (API) . In Java, classes are organized into groups called packages. Each package has a specific name such as java.

In Java, predefined methods are the method that is already defined in the Java class libraries is known as predefined methods. It is also known as the standard library method or built-in method. We can directly use these methods just by calling them in the program at any point.

Runtime class is a subclass of Object class, can provide access to various information about the environment in which a program is running . The Java run-time environment creates a single instance of this class that is associated with a program.