BAEL-1263 Daemon Threads in Java

core-java-concurrency/src/main/java/com/baeldung/concurrent/daemon/NewThread.java

@@ -0,0 +1,9 @@
+package com.baeldung.concurrent.daemon;
+
+public class NewThread extends Thread {
+
+    public void run() {
+        for (int i = 0; i < 10; i++)
+            System.out.println("New Thread is running...");
+    }
+}

core-java-concurrency/src/test/java/com/baeldung/concurrent/daemon/DaemonThreadTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.concurrent.daemon;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class DaemonThreadTest {
+
+    @Test
+    public void whenCallIsDaemon_thenCorrect() {
+        NewThread daemonThread = new NewThread();
+        NewThread userThread = new NewThread();
+        daemonThread.setDaemon(true);
+        daemonThread.start();
+        userThread.start();
+
+        assertTrue(daemonThread.isDaemon());
+        assertFalse(userThread.isDaemon());
+    }
+
+    @Test(expected = IllegalThreadStateException.class)
+    public void givenUserThread_whenSetDaemonWhileRunning_thenIllegalThreadStateException() {
+        NewThread daemonThread = new NewThread();
+        daemonThread.start();
+        daemonThread.setDaemon(true);
+    }
+
+    @Test
+    public void givenUserThread_whenStartThread_thenFalse() {
+        NewThread daemonThread = new NewThread();
+    }
+}