Does System.out.println() effect the code efficiency ?

Question

I used to write & develop codes with system.out.println(). it usually helps me track values and where the problem is coming. And after developed application, I don't remove the system.out.println() because it might helpful after user found any issue it will come back to us, which makes it so easy to track where went to wrong. But one of my superior suggested to remove system.out.println() from codes because its effect the code efficient level. Is this correct?

From my point of view, System.out.print() hardly take bytes on memory, so is it true that developer shouldn't use much system.out.println ??

Thanks in advance.

Answer 1

System.out implementation contains a synchronized block on the output stream.

From PrintStream.java :

      /**
        * Prints a String and then terminate the line.  This method behaves as
        * though it invokes <code>{@link #print(String)}</code> and then
        * <code>{@link #println()}</code>.
        *
        * @param x  The <code>String</code> to be printed.
        */

       public void println(String x) {
           synchronized (this) {
               print(x);
               newLine();
           }
      }

Putting System.out.println a lot will make the entire project to run almost single-threaded, because all thread will waiting for synchronization lock, and make your application begin to crawl.

This means your superior is right.

Alternatively, Use logging framework like log4j instead. You can still configure your log4j to still output to System.out.println by just minor changes in the appender configuration.

Answer 2

use of logging frameworks such as SLF4J is highly recommended. That way by configuration, you can execute these logging statements based on the environement.

eg - DEBUG level on Developer -- WARN on Production, so only critical iformation is logged in production.