Installing Java 7 on Ubuntu

Question

to install java I have always used the classic way from the terminal. I would like to install java manually. I placed the folder of the JDK on the desk and I set environment variables (PATH, CLASSPATH and JAVA_HOME). From the terminal, if I type java -version I get printed

foralobo@ubuntu-vincy:~$ java -version
java version "1.7.0_21"
Java(TM) SE Runtime Environment (build 1.7.0_21-b11)
Java HotSpot(TM) 64-Bit Server VM (build 23.21-b01, mixed mode)

But when I try to install eclipse or netbeans, the system warns by saying that there is no java installed on the machine.

What is missing to compleatare manual installation? (Ubuntu 13.04)

Answer 1

This answer used to describe how to install Oracle Java 7. This no longer works since Oracle end-of-lifed Java 7 and put the binary downloads for versions with security patches behind a paywall. Also, OpenJDK has grown up and is a more viable alternative nowadays.

In Ubuntu 16.04 and higher, Java 7 is no longer available. Usually you're best off installing Java 8 (or 9) instead.

sudo apt-get install openjdk-8-jre

or, f you also want the compiler, get the jdk:

sudo apt-get install openjdk-8-jdk

In Trusty, the easiest way to install Java 7 currently is to install OpenJDK package:

sudo apt-get install openjdk-7-jre

or, for the jdk:

sudo apt-get install openjdk-7-jdk

If you are specifically looking for Java 7 on a version of Ubuntu that no longer supports it, see https://askubuntu.com/questions/761127/how-do-i-install-openjdk-7-on-ubuntu-16-04-or-higher .