Changes for "Guide to finally in Java" (BAEL-3526) (#8237)

* Adding files for finally keyword

* Adding returnFromCatch example.

* Adding empty braces instead of dangling ;

* Return from try, removing the catch block.

* moving to to core-java module

* moving to core-java-lang-2

core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/FinallyExample.java

@@ -0,0 +1,14 @@
+package com.baeldung.finallykeyword;
+
+public class FinallyExample {
+
+    public void printCount(String count) {
+        try {
+            System.out.println("The count is " + Integer.parseInt(count));
+        } catch (NumberFormatException e) {
+            System.out.println("No count");
+        } finally {
+            System.out.println("In finally");
+        }
+    }
+}

core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/FinallyExecutedCases.java

@@ -0,0 +1,53 @@
+package com.baeldung.finallykeyword;
+
+public class FinallyExecutedCases {
+
+    public void noExceptionFinally() {
+        try {
+            System.out.println("Inside try");
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+
+    public void unhandledException() throws Exception {
+        try {
+            System.out.println("Inside try");
+            throw new Exception();
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+
+    public void handledException() {
+        try {
+            System.out.println("Inside try");
+            throw new Exception();
+        } catch (Exception e) {
+            System.out.println("Inside catch");
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+
+    public String returnFromTry() {
+        try {
+            System.out.println("Inside try");
+            return "from try";
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+
+    public String returnFromCatch() {
+        try {
+            System.out.println("Inside try");
+            throw new Exception();
+        } catch (Exception e) {
+            System.out.println("Inside catch");
+            return "from catch";
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+}

core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/FinallyNotExecutedCases.java

@@ -0,0 +1,54 @@
+package com.baeldung.finallykeyword;
+
+public class FinallyNotExecutedCases {
+
+    public void callingSystemExit() {
+        try {
+            System.out.println("Inside try");
+            System.exit(1);
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+
+    public void callingRuntimeHalt() {
+        try {
+            System.out.println("Inside try");
+            Runtime.getRuntime()
+                .halt(1);
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+
+    public void infiniteLoop() {
+        try {
+            System.out.println("Inside try");
+            while (true) {
+            }
+        } finally {
+            System.out.println("Inside finally");
+        }
+    }
+
+    public void daemonThread() throws InterruptedException {
+        Runnable runnable = () -> {
+            try {
+                System.out.println("Inside try");
+            } finally {
+                try {
+                    Thread.sleep(1000);
+                    System.out.println("Inside finally");
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }
+        };
+        Thread regular = new Thread(runnable);
+        Thread daemon = new Thread(runnable);
+        daemon.setDaemon(true);
+        regular.start();
+        Thread.sleep(300);
+        daemon.start();
+    }
+}

core-java-modules/core-java-lang-2/src/main/java/com/baeldung/finallykeyword/PitfallsWhenUsingFinally.java

@@ -0,0 +1,33 @@
+package com.baeldung.finallykeyword;
+
+public class PitfallsWhenUsingFinally {
+
+    public String disregardsUnCaughtException() {
+        try {
+            System.out.println("Inside try");
+            throw new RuntimeException();
+        } finally {
+            System.out.println("Inside finally");
+            return "from finally";
+        }
+    }
+
+    public String ignoringOtherReturns() {
+        try {
+            System.out.println("Inside try");
+            return "from try";
+        } finally {
+            System.out.println("Inside finally");
+            return "from finally";
+        }
+    }
+
+    public String throwsException() {
+        try {
+            System.out.println("Inside try");
+            return "from try";
+        } finally {
+            throw new RuntimeException();
+        }
+    }
+}

core-java-modules/core-java-lang-2/src/test/java/com/baeldung/finallykeyword/PitfallsWhenUsingFinallyUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.finallykeyword;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class PitfallsWhenUsingFinallyUnitTest {
+
+    PitfallsWhenUsingFinally instance = new PitfallsWhenUsingFinally();
+
+    @Test
+    public void testIgnoresException() {
+        String result = instance.disregardsUnCaughtException();
+        assertEquals("from finally", result);
+    }
+
+    @Test
+    public void testIgnoresOtherReturns() {
+        String result = instance.ignoringOtherReturns();
+        assertEquals("from finally", result);
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void testThrowsException() {
+        instance.throwsException();
+    }
+}