FULL PRODUCT VERSION :
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux * 3.19.0-21-generic #21-Ubuntu SMP Sun Jun 14 18:31:11 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

EXTRA RELEVANT SYSTEM CONFIGURATION :
This is both tested on my Ubuntu Machine, my colleagues Windows 7 machine and our Cent OS servers (All 64 bits)

A DESCRIPTION OF THE PROBLEM :
You can create a ScheduledThreadPoolExecutor with 0 core threads (https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/ScheduledThreadPoolExecutor.html#ScheduledThreadPoolExecutor%28int%29)

However if you do and then try to schedule a new task it will allocate 100% of one CPU core until the task is executed.

This can cause big problems for systems where you schedule a shutdown task when the system starts (causing 100% CPU load forever)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run this program and check the CPU load with htop or similar:


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
CPU load should go down, or exception should be thrown.
ACTUAL -
CPU load holds stedy at 100%

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class TestCode {


static ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor( 0 );

public static void main(String[] args) throws IOException
{
executor.schedule( new Runnable(){

@Override
public void run()
{
System.out.println( "END" );
}

}, 30, TimeUnit.SECONDS );
}
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use 1 core thread instead of 0. However that wastes resources