What is composition how it is used?

The main reason to use composition is that it allows you to reuse code without modeling an is-a association as you do by using inheritance . That allows stronger encapsulation and makes your code easier to maintain as Joshua Bloch explains in the 3rd edition of his book Effective Java.16 Oca 2018

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What is whole part relationship in Java?

Aggregation in Java is a relationship between two classes that is best described as a “has-a” and “whole/part” relationship. … The aggregate class contains a reference to another class and is said to have ownership of that class. Each class referenced is considered to be part-of the aggregate class.

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What are the predefined methods?

Predefined Method: 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. 2.7 Mar 2022

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