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u07-3/README.md

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+# Problem 7.3: Compare different Executor implementations
+
+## a)
+
+Two important parameters of class `ThreadPoolExecutor` are `corePoolSize` and
+`maximumPoolSize`. Read about their effect, e.g. at
+<https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/util/concurrent/ThreadPoolExecutor.html>
+or in *Java Concurreny in Practice*, chapter 8. Write an algorithm in pseudo
+code that describes what happens when a new task is submitted and another algorithm
+describing what happens when a task is finished. These two algorithms must use the
+`corePoolSize` the `maximumPoolSize` and the `keepAliveTime`.
+
+### Answer:
+
+```js
+function execute(runnable) {
+	if (runningThreads.size() < corePoolSize) {
+		createNewThread();
+	} else if (runningThreads.size() < maximumPoolSize && queue.isFull()) {
+		createNewThread();
+	}
+}
+
+function onTaskCompletion() {
+	if (runningThreads > corePoolSize) {
+		for (thread : runningThreads) {
+			if (thread.idleTime() > keepAliveTime) {
+				thread.terminate();
+			}
+		}
+	}
+}
+
+```
+
+## b)
+
+Now consider the thread pools created by the factory methods
+`newFixedThreadPool(int nThreads)` and `newCachedThreadPool()`
+mentioned on slide 5-19 (you can find further details at
+<https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/util/concurrent/Executors.html>):
+How can you create these two kinds of thread pool using the general constructor `ThreadPoolExecutor()`?
+
+
+### Answer:
+
+```java
+ThreadPoolExecutor fixedThreadPool = new ThreadPoolExecutor(n, n);
+ThreadPoolExecutor cachedThreadPool = new ThreadPoolExecutor(0, Integer.MAX_VALUE, 60, TimeUnit.SECONDS);
+```