Environment
Mac
mac mini(Mid2010)
OS X 10.11.6 El Capitan
At last of Java development environment setting, you need to install Eclipse which is a IDE (Integrated Development Environment) software.
If you skip installation of IDE like Eclipse, you have to use terminal to compile or execute a Java program by executing compile command or execute command.
Without Ecliplse, it is very inefficient to develop a system. So, usually, IDE is necessary for system development.
Famous IDE is as below;
Eclipse, JBuilder, NetBeans, IntelliJ
Eclipse and IntelliJ are very popular and they can be downloaded without any charge.
Installation of Eclipse
You can download eclipse from the following site.
Eclipse download(http://eclipse.org/downloads/)
Click DOWNLOAD 64 BIT’ on the screen.

Click ‘DOWNLOAD’ button on the showing download screen.
Download will take a while.
*If Downloading takes a lot of time, try to reload your browser.
Download speed might increase.

Downloading is done.

By double-clicking the downloaded file, install Eclipse.
After the following screen shows, install ‘Eclipse IDE for Java EE Developers’.

When the following screen appears, choose an installation folder.
By clicking ‘INSTALL’ button, wait for a while until installation will be done.

After installation is done, the following screen will open. On that screen, click the red rectangle to run Eclipse.

To run a eclipse, it will take for a while. The following screen will show until eclipse complete to run.

After running, ‘Workspace launcher’ window will show and you need to choose the workspage folder.
Workspace is a folder to store all application data like source code files and setting files. You can choose a default workspace without any change on the window.
After you choose the workspace folder, click ‘Launch’ button.

Eclipse will run. You can see the following eclipse development screen.
Now, you complete all installation for Java development.