After installing eclipse on Ubuntu
You can start eclipse smoothly in the terminal:
enter the eclipse directory, and enter the command
./eclipse > /dev/null 2>&1 & in the terminal to start it.
But double-click the eclipse icon in the eclipse directory, and the following will appear when it starts:
A 
Runtime Environment (JRE) or Development Kit (JDK)
must be available in order to run Eclipse. No virtual machine
was found after searching the following locations:
/home/injavawetrust/program/eclipse/jre/bin/java
java in your current PATH
The solution is to go to your eclipse directory in the terminal and enter:
mkdir jre
cd jre
ln -s your JDK directory/bin bin
In this way, you can double-click to start eclipse.