BAEL-4154 IOException Too many open files (#9501)

Co-authored-by: Carlos Grappa <carlos.grappa@mercadolibre.com>

core-java-modules/core-java-exceptions-2/src/test/java/com/baeldung/exceptions/TooManyOpenFilesExceptionLiveTest.java

@@ -0,0 +1,82 @@
+package com.baeldung.exceptions;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.AfterEach;
+
+
+public class TooManyOpenFilesExceptionLiveTest {
+
+    private File tempFile;
+
+    @BeforeEach
+    public void setUp() throws IOException {
+        tempFile = File.createTempFile("testForException", "tmp");
+    }
+
+    @AfterEach
+    public void tearDown() {
+        System.gc();
+        tempFile.delete();
+    }
+
+    @Test
+    public void whenNotClosingResoures_thenIOExceptionShouldBeThrown() {
+        try {
+            for (int x = 0; x < 1000000; x++) {
+                FileInputStream leakyHandle = new FileInputStream(tempFile);
+            }
+            Assertions.fail("Method Should Have Failed");
+        } catch (IOException e) {
+            assertTrue(e.getMessage().toLowerCase().contains("too many open files"));
+        } catch (Exception e) {
+            Assertions.fail("Unexpected exception");
+        }
+    }
+
+    @Test
+    public void whenClosingResoures_thenIOExceptionShouldNotBeThrown() {
+        try {
+            for (int x = 0; x < 1000000; x++) {
+                FileInputStream nonLeakyHandle = null;
+                try {
+                    nonLeakyHandle = new FileInputStream(tempFile);
+                } finally {
+                    if (nonLeakyHandle != null) {
+                        nonLeakyHandle.close();
+                    }
+                }
+            }
+        } catch (IOException e) {
+            assertFalse(e.getMessage().toLowerCase().contains("too many open files"));
+            Assertions.fail("Method Should Not Have Failed");
+        } catch (Exception e) {
+            Assertions.fail("Unexpected exception");
+        }
+    }
+
+    @Test
+    public void whenUsingTryWithResoures_thenIOExceptionShouldNotBeThrown() {
+        try {
+            for (int x = 0; x < 1000000; x++) {
+                try (FileInputStream nonLeakyHandle = new FileInputStream(tempFile)) {
+                    //Do something with the file
+                }
+            }
+        } catch (IOException e) {
+            assertFalse(e.getMessage().toLowerCase().contains("too many open files"));
+            Assertions.fail("Method Should Not Have Failed");
+        } catch (Exception e) {
+            Assertions.fail("Unexpected exception");
+        }
+    }
+}