What are predefined objects in Java?

In Java, there are two types of methods:

You can write user-defined functions in Java to provide functionality that is not available in Oracle CQL or Oracle CQL built-in functions . You can create a user-defined function that returns an aggregate value or a single (non-aggregate) value.

main(): It is a default signature which is predefined in the JVM . It is called by JVM to execute a program line by line and end the execution after completion of this method.

The predefined core objects are Array , Boolean , Date , Function , Math , Number , RegExp , and String .

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.