I was trying to install Jdk 1.7 using
sudo add-apt-repository ppa:openjdk-r/ppa
sudo apt update
sudo apt install openjdk-7-jdk
But getting the below error
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package openjdk-7-jdk is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'openjdk-7-jdk' has no installation candidate**
How Can I Overcome this?