Docker series--methods to install JDK in containers (with examples)

Original URL: Docker series--Methods to install JDK in containers (with examples)_IT Knives Out Blog-CSDN Blog

Introduction

illustrate

This article describes how to install JDK in a container.

Why install JDK?

There are many tools in the JDK, such as jps, jstack, jmap, etc., that can troubleshoot problems.

Objective of this article

To install JDK8 on the docker container in the Ubuntu system, you can call its jps command.

1. Determine the Linux architecture

You can use this command to check whether the architecture is x86 or arm:

uname -m

result: 

2. Download JDK

Download address: https://www.oracle.com/java/technologies/javase/javase8u211-later-archive-downloads.html

The previous step confirmed that the system is x86, 64-bit, so download this:

3. Copy JDK to the host machine

Copy it to this path and decompress it: /work/tool/jdk

The result is as follows:

4. Copy the host JDK to the container

Copy this path to the container: /tool

The command is:

docker cp /work/tool/jdk/jdk1.8.0_341 <容器名字或ID>:/tool

Note: The container must be a first-level directory, otherwise an error will be reported. (Of course, first go to create a new path, then you can specify multi-level directories)

5. Set environment variables

Add the following content at the end of the ~/.bashrc file:

export JAVA_HOME=/tool/
export JRE_HOME=$JAVA_HOME/jre  
export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib  
export PATH=$JAVA_HOME/bin:$PATH

Methods as below:

1. Back up the ~/.bashrc file

cp ~/.bashrc ~/.bashrc.bak

2. Append variables to the ~/.bashrc file

echo "
export JAVA_HOME=/tool/
export JRE_HOME=$JAVA_HOME/jre  
export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib  
export PATH=$JAVA_HOME/bin:$PATH" >> ~/.bashrc

3. Make the new configuration take effect

source ~/.bashrc

6. Test

Test using jps: