Skip to main content

What is the mean of re-usability in Java ?

Object oriented programming is the most preferred programming technique now a day only due to the flexibility of re usability. Re usability is actually an attribute that makes the object oriented programming more flexible and attractive.

As this programming is based on objects. Object is actually a collection of data and functions that are used to operate on that data. These objects are defined as independent entities because the data inside each object represents the attributes of object and functions are used to change these attributes as required by a program.

These objects act just like spare parts of any program. Thus, they are not limited to any specific program; rather they can be used in more than one application as required.
These objects are defined as an independent entity in a program, and afterward they can be used in any other program that needs the same functionality. This reuse of objects helps in reducing the development time of programs.


Example:


Inheritance in Java refers to the feature wherein the code/functionality of one class can be used in another class that extends this class. Example:

public class Animal {
...
..
}

public class Cow extends Animal {
...
..
.
}

Here the class Child extends the class Parent and hence the methods of Parent are available for Child to use. This way we are re-using the code in the parent class in the child class instead of re-writing the whole thing again.
Labels:

Comments

Post a Comment

Please share your experience.....

Popular posts from this blog

error: db5 error(11) from dbenv->open: Resource temporarily unavailable

If rpm command is not working in your system and it is giving an error message( error: db5 error(11) from dbenv->open: Resource temporarily unavailable ). What is the root cause of this issue? How to fix this issue?   just a single command- [root@localhost rpm]# rpm --rebuilddb Detailed error message- [root@localhost rpm]# rpm -q firefox ^Cerror: db5 error(11) from dbenv->open: Resource temporarily unavailable error: cannot open Packages index using db5 - Resource temporarily unavailable (11) error: cannot open Packages database in /var/lib/rpm ^Cerror: db5 error(11) from dbenv->open: Resource temporarily unavailable error: cannot open Packages database in /var/lib/rpm package firefox is not installed [root@localhost rpm]# RPM manage a database in which it store all information related to packages installed in our system. /var/lib/rpm, this is directory where this information is available. [root@localhost rpm]# cd /var/lib/rpm ...
2 comments
Read more

Failed to get D-Bus connection: Operation not permitted

" Failed to get D-Bus connection: Operation not permitted " - systemctl command is not working in Docker container. If systemctl command is not working in your container and giving subjected error message then simple solution of this error is, create container with -- privileged option and also provide init file full path  /usr/sbin/init [root@server109 ~]# docker container run -dit --privileged --name systemctl_not_working_centos1 centos:7 /usr/sbin/init For detailed explanation and understanding I am writing more about it, please have look below. If we have a daemon based program(httpd, sshd, jenkins, docker etc.) running inside a container and we would like to start/stop or check status of daemon inside docker then it becomes difficult for us to perform such operations , because by default systemctl and service  commands don't work inside docker. Normally we run below commands to check services status in Linux systems. [root@server109 ~]# systemctl status ...
4 comments
Read more

AWS cloud automation using Terraform

In this post I'll create multiple resources in AWS cloud using Terraform . Terraform is an infrastructure as code( IAC ) software which can do lots of things but it is superb in cloud automation. To use Terraform we have write code in a high-level configuration language known as Hashicorp Configuration Language , optionally we can write code in JSON as well. I'll create below service using Terraform- 1. Create the key-pair and security group which allow inbound traffic on port 80 and 22 2. Launch EC2 instance. 3. To create EC2 instance use same key and security group which created in step 1 4. Launch Volume(EBS) and mount this volume into /var/www/html directory 5. Upload index.php file and an image on GitHub repository 6. Clone GitHub repository into /var/www/html 7. Create S3 bucket, copy images from GitHub repo into it and set permission to public readable 8 Create a CloudFront use S3 bucket(which contains images) and use the CloudFront URL to update code in /var/w...
Post a Comment
Read more