Difference between revisions of "Java19/Examples"

package pkg1;
public class X {
	@SuppressWarnings("preview")
	private static void foo(Object o) {
	   switch (o) {
	     case Integer i     -> System.out.println("String:");
	     case String s     	-> System.out.println("String: Hello World!");
	     default       	-> System.out.println("Object");
	   }
	}
 
	public static void main(String[] args) {
		foo("Hello World");
	}
}

package pkg1;
public class X {
	@SuppressWarnings("preview")
	private static void foo(Object o) {
	   switch (o) {
	     case Integer I: 
	       System.out.println("Integer"); 
	       System.out.println(I); 
	       break; 
	     case String s when s.length()>1: 
	       System.out.println("String s && s.length()>1"); 
	       System.out.println(s); 
	       break;
	     case String s: 
	       System.out.println("String"); 
	       System.out.println(s);
	       break; 
	     case X x:
	       System.out.println("X"); 
	       System.out.println(x);
	       break;
	     default : System.out.println("Object"); 
	   }
	}
	public static void main(String[] args) {
		foo("Hello World!");
		foo("H");
		foo(new Object());
	}
}

package pkg1;
public class X {
	public static void main(String[] args) {
		foo(Integer.valueOf(11));
		foo(Integer.valueOf(9));
	}
 
	@SuppressWarnings("preview")
	private static void foo(Object o) {
	   switch (o) {
	   case Integer i when i>10:
	     System.out.println("Greater than 10:" + o);
	     break;
	   case Integer j when j>0:
	     System.out.println("Greater than 0:" + o);
	     break;
	   default:
	     System.out.println("Object" + o);
	   }
	}
}

package pkg1;
public class X {
	@SuppressWarnings("preview")
	public static void foo(Object o) throws Exception {
		switch (o) {
			case String s1:
				throw new Exception(s1);
			default:
				break;
		}
	}
 
	public static void main(String[] args) throws Exception {
		foo("hello");
	}
}

package pkg1;
 
record Point(int x, int y) {}
record Length(int l) {}
 
public class A {
	@SuppressWarnings("preview")
	static void printObject(Object obj) {
		if (obj instanceof Point(int x, int y)) {
			System.out.println("Point.x= " + x + "\nPoint.y= " + y);
		} else if (obj instanceof Length(int l)) {
			System.out.println("Lenght.l= " + l);
		} else {
			System.out.println(obj);
		}
	}
 
	public static void main(String[] args) {
		printObject(new Point(10, 20));
		printObject(new Length(100));
	}
}

package pkg1;
public class B {
	static Thread currentThread;
	@SuppressWarnings("preview")
	public static void main(String[] args) {
		Runnable runnable = () -> {
			System.out.println("---Start-Run---");
			if (currentThread.isVirtual()) {
				System.out.println("Virtual Thread:\n\tJava19 feature running with VM arguments:\n\t--enable-preview");
			} else {
				System.out.println("Standard Platform Thread:");
			}
			System.out.println("isVirtual: " + currentThread.isDaemon() + "\nisDaemon : " + currentThread.isDaemon());
			System.out.println("---End---Run---");
		};
		currentThread = new Thread(runnable); // Normal thread is non-daemon by default
		currentThread.start();
		currentThread = Thread.startVirtualThread(runnable); // Virtual thread is by default daemon
		try {
			Thread.sleep(100); // Sleep for 100 ms
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

package pkg1;
public class C {
	static Thread currentThread;
	@SuppressWarnings("preview")
	public static void main(String[] args) {
		Runnable runnable = () -> {
			System.out.println("---Start-Run---");
			if (currentThread.isVirtual()) {
				System.out.println("Virtual Thread:\n\tJava19 feature running with VM arguments:\n\t--enable-preview");
			} else {
				System.out.println("Standard Platform Thread:");
			}
			System.out.println("isVirtual: " + currentThread.isDaemon() + "\nisDaemon : " + currentThread.isDaemon());
			System.out.println("---End---Run---");
		};
		currentThread = new Thread(runnable); // Normal thread is non-daemon by default
		currentThread.start();
		Thread.Builder threadBuilder = Thread.ofVirtual().name("Virtual-Thread", 1);
		currentThread = threadBuilder.start(runnable); // Virtual thread is by default daemon
		try {
			Thread.sleep(100); // Sleep for 100 ms
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

package pkg1;
 
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
 
public class D {
	static ExecutorService service;
 
	@SuppressWarnings("preview")
	public static void main(String[] args) {
		Runnable runnable = () -> {
			System.out.println("---Start-Run---");
			System.out.println(
					"VirtualThreadPerTaskExecutor:\n\tJava19 feature running with VM arguments:\n\t--enable-preview");
			System.out.println("---End---Run---");
		};
		service = Executors.newVirtualThreadPerTaskExecutor();
		service.execute(runnable);
		try {
			Thread.sleep(100); // Sleep for 100 ms
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}