I can't install JRE and JDK on my Ubuntu 18.04 LTS

I can't install both the JRE and JDK. First of all, I have not attempted to install the JDK, but I assume that if I did, it wouldn't work because you need to install the JRE.

Second, I can't install the JRE, I have followed a lot of tutorials like , and the java and javac commands do not work. It says, Command 'java' not found, but can be installed with: ... and I am not sure what openjdk is. Please help me.

P.S. I have also searched Ask Ubuntu questions, but none of them helped.

P.P.S. Here's the log:

$ sudo apt-get install oracle-java8-installer sudo apt-get install oracle-java8-installer Reading package lists... Done Building dependency tree Reading state information... Done oracle-java8-installer is already the newest version (8u171-1~webupd8~0). 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] y Setting up oracle-java8-installer (8u171-1~webupd8~0) ... Using wget settings from /var/cache/oracle-jdk8-installer/wgetrc Downloading Oracle Java 8... --2018-05-22 05:12:57-- Resolving download.oracle.com (download.oracle.com)... 23.41.237.84 Connecting to download.oracle.com (download.oracle.com)|23.41.237.84|:80... connected. HTTP request sent, awaiting response... 302 Moved Temporarily Location: [following] --2018-05-22 05:12:58-- Resolving edelivery.oracle.com (edelivery.oracle.com)... 184.87.246.212, 2001:fe0:10:181::2d3e, 2001:fe0:10:195::2d3e Connecting to edelivery.oracle.com (edelivery.oracle.com)|184.87.246.212|:443... connected. HTTP request sent, awaiting response... 302 Moved Temporarily Location: [following] --2018-05-22 05:12:59-- Connecting to download.oracle.com (download.oracle.com)|23.41.237.84|:80... connected. HTTP request sent, awaiting response... 416 Requested Range Not Satisfiable The file is already fully retrieved; nothing to do. Download done. Removing outdated cached downloads... sha256sum mismatch jdk-8u171-linux-x64.tar.gz Oracle JDK 8 is NOT installed. dpkg: error processing package oracle-java8-installer (--configure): installed oracle-java8-installer package post-installation script subprocess returned error exit status 1 Errors were encountered while processing: oracle-java8-installer E: Sub-process /usr/bin/dpkg returned an error code (1) Reading package lists... Done Building dependency tree Reading state information... Done oracle-java8-installer is already the newest version (8u171-1~webupd8~0). 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] y Setting up oracle-java8-installer (8u171-1~webupd8~0) ... Using wget settings from /var/cache/oracle-jdk8-installer/wgetrc Downloading Oracle Java 8... --2018-05-22 05:12:57-- Resolving download.oracle.com (download.oracle.com)... 23.41.237.84 Connecting to download.oracle.com (download.oracle.com)|23.41.237.84|:80... connected. HTTP request sent, awaiting response... 302 Moved Temporarily Location: [following] --2018-05-22 05:12:58-- Resolving edelivery.oracle.com (edelivery.oracle.com)... 184.87.246.212, 2001:fe0:10:181::2d3e, 2001:fe0:10:195::2d3e Connecting to edelivery.oracle.com (edelivery.oracle.com)|184.87.246.212|:443... connected. HTTP request sent, awaiting response... 302 Moved Temporarily Location: [following] --2018-05-22 05:12:59-- Connecting to download.oracle.com (download.oracle.com)|23.41.237.84|:80... connected. HTTP request sent, awaiting response... 416 Requested Range Not Satisfiable The file is already fully retrieved; nothing to do. Download done. Removing outdated cached downloads... sha256sum mismatch jdk-8u171-linux-x64.tar.gz Oracle JDK 8 is NOT installed. dpkg: error processing package oracle-java8-installer (--configure): installed oracle-java8-installer package post-installation script subprocess returned error exit status 1 Errors were encountered while processing: oracle-java8-installer E: Sub-process /usr/bin/dpkg returned an error code (1) 

edit/P.S. To those who thinks that this is a duplicate, you are mistaken. I am not using a virtual machine, I tried and tried again 'til it succeeded, and it did. My problem now is, the JDK wasn't installed. I found this out when I installed NetBeans and no JDK was installed, but the JRE was installed.

2 Answers

JDK includes JRE with it, so you only need JDK for both.

Your terminal session shows that your Oracle Java 8 JDK installer download was corrupted (sha256sum mismatch jdk-8u171-linux-x64.tar.gz). To fix the problem and install again:

sudo rm /var/cache/oracle-jdk8-installer/*.tar.gz sudo apt-get update sudo apt-get install --reinstall oracle-java8-installer 

If you install jdk, you don't need to install jre.

What happens if you just do

sudo apt-get install default-jdk