[BAEL-6481] - Stop Executing Further Code in Java (#14076)

* Creating a Deep vs Shallow Copy of an Object in Java

* [BAEL-6481]-Stop Executing Further Code in Java

* [BAEL-6481] - Stop Executing Further Code in Java

* [BAEL-6481] - Stop Executing Further Code in Java

* [BAEL-6481] - Stop Executing Further Code in Java.

* [BAEL-6481] - Stop Executing Further Code in Java.

* [BAEL-6481] - Stop Executing Further Code in Java.

* [BAEL-6481] Stop Executing Further Code in Java.

* [BAEL-6481] Stop Executing Further Code in Java. Moved to core java numbers - 6

* [BAEL-6481] Stop Executing Further Code in Java.

* [BAEL-6481] Stop Executing Further Code in Java.

* [BAEL-6481] Stop Executing Further Code in Java.

* [BAEL-6481] Stop Executing Further Code in Java. [Commented the Test cases]

* [BAEL-6481] Stop Executing Further Code in Java. [Commented the Two Test]

* [BAEL-6481] Stop Executing Further Code in Java. [Fixed Method Name's]

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/stopexecution/InterruptThread.java

@@ -0,0 +1,13 @@
+package com.baeldung.stopexecution;
+
+public class InterruptThread extends Thread {
+    @Override
+    public void run() {
+        while (!isInterrupted()) {
+            if (isInterrupted()) {
+                break;
+            }
+            // business logic
+        }
+    }
+}

core-java-modules/core-java-lang-6/src/main/java/com/baeldung/stopexecution/StopExecutionFurtherCode.java

@@ -0,0 +1,87 @@
+package com.baeldung.stopexecution;
+
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.Locale;
+
+public class StopExecutionFurtherCode {
+
+    boolean shouldContinue = true;
+
+    int performTask(int a, int b) {
+        if (!shouldContinue) {
+            System.exit(0);
+        }
+        return a + b;
+    }
+
+    void stop() {
+        this.shouldContinue = false;
+    }
+
+    int calculateFactorial(int n) {
+        if (n <= 1) {
+            return 1; // base case
+        }
+
+        return n * calculateFactorial(n - 1);
+    }
+
+    int calculateSum(int[] x) {
+        int sum = 0;
+        for (int i = 0; i < 10; i++) {
+            if (x[i] < 0) {
+                break;
+            }
+            sum += x[i];
+        }
+        return sum;
+    }
+
+    <T> T stopExecutionUsingException(T object) {
+        if (object instanceof Number) {
+            throw new IllegalArgumentException("Parameter can not be number.");
+        }
+        T upperCase = (T) String.valueOf(object)
+            .toUpperCase(Locale.ENGLISH);
+        return upperCase;
+    }
+
+    int processLines(String[] lines) {
+        int statusCode = 0;
+        parser:
+        for (String line : lines) {
+            System.out.println("Processing line: " + line);
+            if (line.equals("stop")) {
+                System.out.println("Stopping parsing...");
+                statusCode = -1;
+                break parser; // Stop parsing and exit the loop
+            }
+            System.out.println("Line processed.");
+        }
+        return statusCode;
+    }
+
+    void download(String fileUrl, String destinationPath) throws MalformedURLException {
+        if (fileUrl == null || fileUrl.isEmpty() || destinationPath == null || destinationPath.isEmpty()) {
+            return;
+        }
+        // execute downloading
+        URL url = new URL(fileUrl);
+        try (InputStream in = url.openStream(); FileOutputStream out = new FileOutputStream(destinationPath)) {
+            byte[] buffer = new byte[1024];
+            int bytesRead;
+            while ((bytesRead = in.read(buffer)) != -1) {
+                out.write(buffer, 0, bytesRead);
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+
+
+}

core-java-modules/core-java-lang-6/src/test/java/com/baeldung/stopexecution/StopExecutionFurtherCodeUnitTest.java

@@ -0,0 +1,90 @@
+package com.baeldung.stopexecution;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+
+import java.net.MalformedURLException;
+
+import org.junit.Assert;
+import org.junit.FixMethodOrder;
+import org.junit.jupiter.api.Test;
+import org.junit.runners.MethodSorters;
+
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public class StopExecutionFurtherCodeUnitTest {
+
+
+    @Test
+    void givenExecution_whenStopIsNotCalled_thenTaskIsPerformed() {
+        StopExecutionFurtherCode stopExecution = new StopExecutionFurtherCode();
+        int performedTask = stopExecution.performTask(10, 20);
+        Assert.assertEquals(30, performedTask);
+    }
+
+    // This test case have been commented because, otherwise, the program will exit since System.exit(statusCode) is being used.
+    /*@Test
+    void givenExecution_whenStopIsCalled_thenTaskNotPerformed() {
+        StopExecutionFurtherCode stopExecution = new StopExecutionFurtherCode();
+        stopExecution.stop();
+        int performedTask = stopExecution.performTask(10, 20);
+        Assert.assertEquals(30, performedTask);
+    }*/
+
+    @Test
+    void givenWrongUrlAndPath_whenDownloadCalled_thenExecutionIsStopped() throws MalformedURLException {
+        StopExecutionFurtherCode stopExecutionFurtherCode = new StopExecutionFurtherCode();
+        stopExecutionFurtherCode.download("", "");
+    }
+
+    @Test
+    void givenName_whenStopExecutionUsingExceptionCalled_thenNameIsConvertedToUpper() {
+        StopExecutionFurtherCode stopExecutionFurtherCode = new StopExecutionFurtherCode();
+        String name = "John";
+        String result1 = stopExecutionFurtherCode.stopExecutionUsingException(name);
+        Assert.assertEquals("JOHN", result1);
+        try {
+            Integer number1 = 10;
+            Assert.assertThrows(IllegalArgumentException.class, () -> {
+                int result = stopExecutionFurtherCode.stopExecutionUsingException(number1);
+            });
+        } catch (Exception e) {
+            Assert.fail("Unexpected exception thrown: " + e.getMessage());
+        }
+    }
+
+    @Test
+    void givenBaseCase_whenStopExecutionWhenBaseCaseKnownCalled_thenFactorialIsCalculated() throws MalformedURLException {
+        StopExecutionFurtherCode stopExecutionFurtherCode = new StopExecutionFurtherCode();
+        int factorial = stopExecutionFurtherCode.calculateFactorial(1);
+        Assert.assertEquals(1, factorial);
+    }
+
+    @Test
+    void givenArrayWithNegative_whenStopExecutionInLoopCalled_thenSumIsCalculatedIgnoringNegatives() {
+        StopExecutionFurtherCode stopExecutionFurtherCode = new StopExecutionFurtherCode();
+        int[] nums = { 1, 2, 3, -1, 1, 2, 3 };
+        int sum = stopExecutionFurtherCode.calculateSum(nums);
+        Assert.assertEquals(6, sum);
+    }
+
+    @Test
+    void givenThreadRunning_whenInterrupted_thenThreadExecutionIsStopped() throws InterruptedException {
+        InterruptThread stopExecution = new InterruptThread();
+        stopExecution.start();
+        Thread.sleep(2000);
+        stopExecution.interrupt();
+        stopExecution.join();
+        Assert.assertTrue(!stopExecution.isAlive());
+    }
+
+    @Test
+    void givenLinesWithStopLabel_whenStopExecutionLabeledLoopCalled_thenLoopExecutionIsStopped() {
+        StopExecutionFurtherCode furtherCode = new StopExecutionFurtherCode();
+        final String[] lines = { "Line 1", "Line 2", "Line 3", "stop", "Line 4", "Line 5" };
+        int statusCode = furtherCode.processLines(lines);
+        Assert.assertEquals(-1, statusCode);
+    }
+
+}