Remove java 8 and install java 7 in Ubuntu

There are times when you need a specific version of Java to be installed instead of the latest version. The following post will brief on the steps required to remove Java 8 and install Java 7 in Ubuntu 16.04

Always use the latest version of Java as there are quite a lot of bug fixes and security vulnerability has been fixed.

Removing Java 8
Open Terminal and enter the following commands.

sudo update-alternatives –remove-all java
sudo update-alternatives –remove-all javac
sudo update-alternatives –remove-all javaws
sudo rm -rf /usr/lib/jvm/jdk1.8.0

Install Java 7
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update

Since Java 7 is no longer available in their repository, you need to manually download it from Oracle site.

Once the JDK 7 tar (jdk-7u80-linux-x64.tar.gz) is downloaded. Paste it in the below location

Now run the following command
sudo apt-get install oracle-java7-installer

After installation you also need to update alternatives by running the following command.

sudo update-alternatives –install “/usr/bin/java” “java” “/usr/lib/jvm/java-7-oracle/jdk1.7.0_80/bin/java” 1
sudo update-alternatives –install “/usr/bin/javac” “javac” “/usr/lib/jvm/java-7-oracle/jdk1.7.0_80/bin/javac” 1
sudo update-alternatives –install “/usr/bin/javaws” “javaws” “/usr/lib/jvm/java-7-oracle/jdk1.7.0_80/bin/javaws” 1

Once the above steps are completed. Check the java version from terminal
javac -version
java -version

It should display jdk 1.7

Tech, Developer conference that one should not miss!

Working as a developer, tech lead or an architect, one thing that you should continue pursue is learning. Either it could be new technologies &  framework or any new disruptive ideas or tools.

Some of the key developer conferences that you need to block your calendar are:

  • Apple WWDC
  • Google I/O
  • Facebook Developer conference
  • Open source summit.

If you are not able to attend one, you can still watch those couple of weeks later as part of their youtube channel.

I stumbled upon this blog which has the list of all the dev conference that happens throughout the world.

if you are looking for a list of the events for the year, the following site covers exhaustive list.

Quick Calculation using Windows Calculator App

If you are looking for an application for calculating the difference between 2 dates, or to find the mortgage, vehicle lease, fuel economy. Then you do not have to go to or download MS Office spreadsheets. Some of the basic calculation needs are available in the calculator application as part of Windows Operating System.


The windows Operating system that i use is Windows 7 Ultimate.

Windows update not working..

If you are facing issues on windows 7 not updating the patches after the first install. There could be issues specific to few pre-requisite installed not updated properly. After a long search on the internet finally able to find the list of updates required to fix this issue.

    For 64 bit

    for 32 bit

The following link has the full details.

[Fix] Windows 7 Keeps Checking for Updates for Hours

Ad settings in your Google account

If you have a android phone and wondering how ads are shown based on the google search or youtube videos that you watched previously. The main reason for this is google ads. Google records all the activity that you perform and use that to show you relevant ads. If you are very particular and do not want your activity to be tracked, then you need to change your ad settings.

Login to Google Ad settings link

turn off Ads based on your interest.

If you are really not particular on this then have this option “ON”. At times you will get to see ad’s and info that you are looking for.

Yeoman scaffolding tool

If you are working for Java Script project, then you would have heard about Yeoman. Yeoman generator creates a scaffolding project for you. The projects has all the best of the breed frameworks available within it.

How to install yeoman generator

Go to to Yeoman site

Select  a specific generator for your project. E.g Angular, React, etc.

Node.js (npm) should be installed as pre-requisite.

Step 1: Install yeoman

npm install -g yo

Step 2: install the generator from 

npm install generator-angular

Step 3:  install generator

yo angular

git behind corporate proxy

If you have trouble cloning github repository from your company’s PC. Then you need to set-up Git for additional configuration to go through corporate proxy.

For windows:

You need to download and install git client in windows PC. (GitBash)

For Mac

You can use Terminal. Git is pre-installed.

open Gitbash or Terminal and enter the following command

git config –global http.proxy ‘http://<domain name>\<user id>:<password>@<proxy server>:proxy port’

git config –global https.proxy ‘http://<domain name>\<user id>:<password>@<proxy server>:proxy port’

If your password contains special characters, the you need to use escape characters.

E.g if your password contains ‘@’ symbol then ‘@’ needs to be replaced with ‘%40’

node.js – npm behind corporate proxy

If you have trouble running npm behind a corporate proxy which uses a domain, username, password combination, then you can do the following steps to fix it.

Corporate Proxy Rules

User: <Domain name>\<user id>

Password: <Password>

Proxy-ip: ip address or domain name of proxy server

Proxy-port: Port of the proxy ip.


Node.js should be installed.


Open Command prompt (WIndows PC)/ Terminal (Mac)

type in the following command

npm config set proxy=http://<Domain name>%5C<user id>:<Password>@<Proxy-ip>:<Proxy port>

npm config set https-proxy=http://<Domain name>%5C<user id>:<password>@<proxy-ip>:<proxy port>

Important steps: Open .npmrc file and validate the settings. Sometime npm will update your password with escape characters. If you see any discrepancy, go ahead and make changes directly in the file.

The file is located under

for windows: c:\Users\<user id>\.npmrc

for mac

type cd ~

This will be user directory.

Word of caution:

npm does not like special characters in the password like ‘-‘, ‘#’, ‘$’ etc.  If your corporate policy mandates you to have special characters in password, then safely choose ‘@’