How to write a copy constructor in java

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Typecasting is required as the clone method returns Object type, whereas Copy Constructor does not need such typecasting. In step 5, we have updated the values of a and b by using the reference variable n, In the existing memory, the values of a and b are replaced with 50 and 40 respectively as shown in the memory.

Let's see a simple example program step by step to understand the concept.

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In step 6, when we created a new object of the class, a new memory is allocated by JVM but we did not get updated values in the new memory as shown in the above figure because JVM did not copy the updated data into the new memory. Take a look. As sweet was having true value for m1, m2's sweet will be having true value too.

Key points: 1. Next, when we have changed the value of sweet for object m1 from true to false and called flavor method for m1, it shows the result as "Mango is not sweet".

How to write a copy constructor in java

To copy the data from one memory to another memory, we will use a copy constructor concept. In the main when we created the first object of the class and passed true as an argument, the sweet boolean data members get the signed value of m1. When we created the second object with reference variable m2 and passed m1 as an argument, the copy constructor is called. Let's see a simple example program step by step to understand the concept. If we call flavor for m2, the result shows "Mango is sweet" 3. We need to use the new operator inside the Copy Constructor for it to be deep copied. Key points: 1. Java always passes objects as the reference, but the references are passed by value. The Copy Constructor helps us overcome the design issues of the clone method. Take a look. Now, you will get updated data inside the new memory location with the help of a copy constructor. It gives us the complete control over object copy, we can even mix both Deep Copy and Shallow Copy for different attributes of the class.

Now, you will get updated data inside the new memory location with the help of a copy constructor. So, we can say that a copy constructor is a constructor which is used for copying the data from one memory location object to another memory location new object meanwhile object creation.

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Copy Constructor in Java Example