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Object as Parameter in Java

Similar to primitive types, Java makes it easier to give objects as parameters to methods. It is crucial to recognize that sending an object as an argument transmits merely a reference to the item-not a duplicate of it. It means that any changes made to the object inside the method will have an immediate impact on the original object. In this section, we will discuss passing an object as a parameter in Java.

Object Passing as Parameters


  1. Java is a pass-by-value language.
  2. When forwarding objects, only the object's reference-not the actual object-is duplicated.


  1. Object passing supports encapsulation.
  2. Methods act as interfaces, controlling access to the internal state of an object.

Immutability Considerations

  1. Care is needed with immutable objects.
  2. Methods should avoid modifying the state and return new instances if necessary.

Null Checks and Defensive Programming

  1. Include null checks to handle potential null object parameters.
  2. Defensive programming ensures robustness and prevents null pointer exceptions.

Code Reusability and Modularity:

  1. Object passing enhances code reusability.
  2. Promotes modularity by allowing methods to operate on different object instances.

Understanding the Concept

Let's examine the fundamental syntax and application of Java's "object as parameter" now.


Attribute 1: 20
Attribute 2: World
Attribute 3: 6.28


The method myMethod()takes an object of the same class as an input, enabling the method to work with the provided object and access its properties and methods.

Passing Object in an Array


Original Names:
Modified Names:


A method called modifyPersonNames() has been added to the ObjectPassingExample class. It modifies the names of all the individuals in the array.

The "people" array is generated in the main method using two Person objects, originally named "John" and "Alice."

The modifyPersonNames() method is called after the original names are printed, changing them to "Jane."

Passing Object in an ArrayList


Original Names:
Modified Names:

Advantages of Passing an Object as a Parameter

1. Flexibility

Object parameters provide flexibility in handling different types of objects. A method can accept various objects as parameters, enhancing the adaptability of the code.

2. Reusability of Code

It is possible to create methods that are particular to an object type by using passing objects. Because several instances of the same object can utilize the same method, this encourages code reusability.

3. Encapsulation

When methods work with objects, they provide more support for encapsulation and other object-oriented programming concepts. The object contains both data and behavior, which encourages a simpler design.


Understanding Java's object-passing syntax is necessary for writing effective object-oriented code. By utilizing this feature, code can become more legible, modular, and clean. When you take part in coding tests and projects, remember the advantages and best practices discussed here to enhance your Java programming abilities.

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