JDK (Java Development Kit)
- Don't confuse with JRE (runtime environment) - No javac
- Ver 15 or above is a must.
- 'Major/minor error' is due to version incompatibility

printf
- Original version from FORTRAN	
- Easiest for precise printing

MinGW
- Provides g++ compiler (and many others) for use on PC

Processes
- Heavyweight processes have their own identity in the system. Elements include:
  * Process id (pid)
  * Data space
  * Parent pid
  * Many other facets
- Lightweight processes run within a heavyweight process
  * Threads
    > All share the data space.
    > Program main is in main thread.
    > Threads can have names.
    > Event dispatching thread is used by listeners to send events to the appropriate listening object
    > Java's garbage collector runs as a tread in the java run-time environment, i.e. java.exe (or just java)
  * Java commonly uses threads, not hvywt processes for concurrent programming.

Threads (more)
- Thread code is in a run() method. 
  * Activated by calling the thread's start() method
  * One thread can wait for another using join()
  * A thread  that might hog CPU time might best call yield() periodically.
  * Threads terminate when done.
  * Callers aren't suspended by starting a thread unless they use join() to wait for its completion.

JDBC (Java Database Connectivity)
- Import the jdbc classes using import statements
- load the jdbc driver
- Connect to the database (getConnection())
- Submit queries, inserts, updates and process responses (often via a statement)
  * Updates are used to add to, modify, or remove from a table in the database
  * Queries are used to look things up in the database
- Must commit (make permanent) any changes. This can be circumvented by using auto-commit.


Disconnect from the database