Problem 1:
Unable to make private java.nio.DirectByteBuffer(long,int) accessible: module java.base does not "opens java.nio" to unnamed module
Solution:
Apache Spark is NOT COMPATIBLE with Java 16.
When downloading a JDK for Spark, Java 11 is the safest choice.
I am using Java 16, so need to shift JDK to 11.
Download JDK11 installer from Oracle. Install.
File - Project Structure - Platform Settings - + - add JDK11
File - Project Structure - Project - SDK - choose JDK11
Rebuild the project. Run.
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