1. wat komt hier uit? ------------------------------------------------------------------------
public class HelloGoodbye {
public static void main(String[] args) {
try {
System.out.println("Hello world");
System.exit(0);
} finally {
System.out.println("Goodbye world");
}
}
}
2. wat zegt de compiler hier? ---------------------------------------------------------------------
class FooClass {
public static void bar(String arg) {
System.out.println("arg = " + arg);
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System.out.println("Done!");
}
}
3. hoe refactoren we dit volgens Fowler met SPLITTING LOOP? ----------------------------------------------------------
Start with this code.
private Person [] people; void printValues() { double averageAge = 0; double totalSalary = 0; for (int i = 0; i < people.length; i++) { averageAge += people[i].age; totalSalary += people[i].salary; } averageAge = averageAge / people.length; System.out.println(averageAge); System.out.println(totalSalary); }
4. How can you fit 20 clowns into a Volkswagen? Two classes are given: an empty Clown class, and a Volkswagen class to which you can add clowns. When you try to add a Clown, it is checked that it isn’t already full. But if you just try hard enough, there’s always room for some extra clowns…
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package clowns;
public class Clown {
}
package clowns;
import java.util.HashSet;
import java.util.Set;
public class Volkswagen {
private static final int CAPACITY = 5;
private Set<Clown> clowns = new HashSet<Clown>();
public synchronized void add(Clown clown) {
if (clowns.size() >= CAPACITY) {
throw new IllegalStateException("I'm full");
} else {
clowns.add(clown);
}
}
public synchronized void done() {
if (clowns.size() == 20) {
// The goal is to reach this line
System.out.println("I'm a Volkswagen with 20 clowns!");
}
}
}
Write a class that pushes 20 clowns into the little car, and reaches the marked line. Here is one that won’t really work, just to get you started:
package you;
import clowns.Clown;
import clowns.Volkswagen;
public class You {
public static void main(String args[]) {
// TODO put 20 clowns into a Volkswagen
Volkswagen vw = new Volkswagen();
for (int i = 0; i < 20; i++) {
vw.add(new Clown());
}
vw.done();
}
}