The ThreadPoolExecutor constructor throws an IllegalArgumentException if the corePoolSize is greater than maximumPoolSize, but the method called "setCorePoolSize(int corePoolSize)"
(which overrides values set in the constructor) allows corePoolSize > maxPoolSize. No IllegalArgumentException is thrown in that case. So the constructor checks the values but the setCorePoolSize method does not.

import java.util.Timer;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class Main {

    static void print(ThreadPoolExecutor pool) {
        System.out.printf("poolSize=%d core=%d max=%d%n",
            pool.getPoolSize(),
            pool.getCorePoolSize(),
            pool.getMaximumPoolSize());
    }

    public static void main(String[] args) {
        final int CORE = 2,
                  MAX = 10,
                  KEEP_ALIVE_TIME = 30,
                  QUEUE_MAX_SIZE = 25;
        final BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<Runnable>(QUEUE_MAX_SIZE);
        final ThreadPoolExecutor executor = new ThreadPoolExecutor(CORE, MAX, KEEP_ALIVE_TIME, TimeUnit.SECONDS, workQueue);
        print(executor);
        executor.setCorePoolSize(MAX+1);
        print(executor);
    }
}

prints:
poolSize=0 core=2 max=10
poolSize=0 core=11 max=10