🚀 Programming Example

Instance Variable in Java Programming

👁 5,096 Views

💻 Practical Program

📘 Step Learning

Instance variable in java is used by Objects to store their states. Variables which are defined without the STATIC keyword and are Outside any method declaration are Object specific and are known as instance variables. They are called so because their values are instance specific and are not shared among instances.

📌 Information & Algorithm

💻 Program Code

 class InstanceVariable {
int data=50;//instance variable

public static void main(String []args) {
      /* In this example if you want to access instanec variable'data' then you 
      have to create an instane of InstancVariable class like this*/
      InstanceVariable iv = new InstanceVariable();
      /* here iv is the name of the object or instance of the
	   InstanceVariable class */
      System.out.println(iv.data);
      /* to access the instance variable 'data' you have to write iv.data

   }
}

🖥 Program Output

50
Press any key to continue . . .

📘 Explanation

Rules for Instance variable in Java

Instance variables can use any of the four access levels
They can be marked final
They can be marked transient
They cannot be marked abstract
They cannot be marked synchronized
They cannot be marked strictfp
They cannot be marked native
They cannot be marked static

Cheatsheet

Public, Private, Protected?all 3 access modifiers can be applied to Instance Variable(Default?also).
Instance variable will get default value means instance variable can be used without initializing it. Same is not true for?Local Variable.
Instance Variable?can be marked?final.
Instance Variable?can be marked?transient.
Instance Variable?cannot be?abstract.
Instance Variable?can not?have?synchronized?modifier.
Instance Variable?can not?have?strictfp?modifier.
Instance Variable?can not?have?the native?modifier.
Instance Variable?can not have?Static?modifier as it will become Class level variable.

INSTANCE VARIABLE TYPE	DEFAULT VALUE
boolean	false
byte	(byte)0
short	(short) 0
int	0
long	0L
char	u0000
float	0.0f
double	0.0d
Object	null

🎯 How to learn from this example

First understand the algorithm carefully. Then study the program line-by-line and compare it with the output. Finally, review the explanation section to strengthen your logic and programming understanding.

🔥 Practice suggestion

Rewrite the program without looking at the code. Modify values, conditions or logic and run it again. This helps improve confidence and strengthens coding skills much faster.

⚡ Quick Practice Flow

Follow this learning sequence for better understanding.

Read the topic carefully
Understand the algorithm
Study the code line-by-line
Check the output result
Practice by modifying logic