After installing the Java JDK, why do I need to install the JRE

Question

The JDK contains the JRE, but even after installing the JDK and installing JAVA_HOME, whenever I test Java using webstart or the Java test page , it says that Java is not installed. Do I need to install JRE?

Answer 1

Ok, thanks for a_horse_with_no_name. I found that the reason is that the JRE is not just Oracle, perhaps JRE developers like Weblogic use the JRockit JRE. And in order to separate the JRE development environment from the oracle installation run time, the installation does not receive the latest JRE installation as the home JRE and the public one. Plus The public installation of JRE uses registry entries; to run Java applications private does not work.

In the development image, the user can also use stack trace or dump memory, isolated from the public. A class version exception may also occur when updating a public JRE when jdk is newer. Or we can install private from the command line during installation, for example

jdk.exe /s ADDLOCAL="ToolsFeature,SourceFeature,PublicjreFeature" 

An earlier version may have public installations after installing the JDK.

Answer 2

For java to work in the browser, you need a java browser plugin that does not come with the JDK.