debugging elasticsearch github project on intellij - elasticsearch

Question

I have cloned the elasticsearch github repo on my linux machine and i have java 8. I go to the directory elasticsearch and run the command "gradle build" . But it throws me error saying there is an error in :
Build file '/home/tracxn-lp-354/Documents/sanchit/elasticsearch/benchmarks/build.gradle' line: 31
What went wrong:
A problem occurred evaluating project ':benchmarks'.
Failed to apply plugin [id 'elasticsearch.build']
Java 1.9 or above is required to build Elasticsearch

Answer 1

As the error says, you need to install a newer version of java.
What version of java does it say it's running?
java -version
If it doesn't say 1.9 then you need an upgrade!
sudo apt-get purge openjdk*
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java9-installer
java -version
sudo apt-get install oracle-java9-set-default
--
Once all this is done:
Make sure to open Project Structure in IntelliJ and navigate to:
Project->Project SDK.
Specify the latest version of the Java JDK (9) and click Apply.

Answer 2

First of all, make sure you installed Java 9 (JDK 9 is required to build Elasticsearch).
Now, run the following command from Elasticsearch root directory (it automatically configures IDE):
gradle idea
After that, open Elasticsearch project from IntelliJ IDEA with enabled Gradle auto-import. This step is important, because it setups correct project structure for IDEA (content root, source folders, etc):
File -> New -> Project from Existing Sources... -> Import Gradle Project
And make sure that Project SDK is set to the Java version 9.
Now, to debug Elasticsearch, go to the Run -> Edit Configurations menu and add the following configurations:
Add breakpoint somewhere, for example in:
server/src/main/java/org/elasticsearch/bootstrap/Elasticsearch.java
And run Debug 'Elasticsearch' (Shift + F9 in IntelliJ IDEA).
P.S. The process might be time consuming, so be patient and enjoy the result!