[BAEL-13505] Move articles out of core-java part 1

core-java-modules/core-java-exceptions/src/test/java/com/baeldung/exceptions/GlobalExceptionHandlerUnitTest.java

@@ -0,0 +1,64 @@
+package com.baeldung.exceptions;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.slf4j.LoggerFactory;
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.classic.spi.LoggingEvent;
+import ch.qos.logback.core.Appender;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.verify;
+
+@RunWith(MockitoJUnitRunner.class)
+public class GlobalExceptionHandlerUnitTest {
+
+    @Mock
+    private Appender<ILoggingEvent> mockAppender;
+
+    @Captor
+    private ArgumentCaptor<LoggingEvent> captorLoggingEvent;
+
+    @Before
+    public void setup() {
+        final Logger logger = (Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
+        logger.addAppender(mockAppender);
+
+        Handler globalExceptionHandler = new Handler();
+        Thread.setDefaultUncaughtExceptionHandler(globalExceptionHandler);
+    }
+
+    @After
+    public void teardown() {
+        final Logger logger = (Logger) LoggerFactory.getLogger(Logger.ROOT_LOGGER_NAME);
+        logger.detachAppender(mockAppender);
+    }
+
+    @Test
+    public void whenArithmeticException_thenUseUncaughtExceptionHandler() throws InterruptedException {
+
+        Thread globalExceptionHandlerThread = new Thread() {
+            public void run() {
+                GlobalExceptionHandler globalExceptionHandlerObj = new GlobalExceptionHandler();
+                globalExceptionHandlerObj.performArithmeticOperation(99, 0);
+            }
+        };
+
+        globalExceptionHandlerThread.start();
+        globalExceptionHandlerThread.join();
+
+        verify(mockAppender).doAppend(captorLoggingEvent.capture());
+        LoggingEvent loggingEvent = captorLoggingEvent.getValue();
+
+        assertThat(loggingEvent.getLevel()).isEqualTo(Level.INFO);
+        assertThat(loggingEvent.getFormattedMessage()).isEqualTo("Unhandled exception caught!");
+    }
+
+}

core-java-modules/core-java-exceptions/src/test/java/com/baeldung/java8/JavaTryWithResourcesLongRunningUnitTest.java

@@ -0,0 +1,92 @@
+package com.baeldung.java8;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.Date;
+import java.util.Scanner;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class JavaTryWithResourcesLongRunningUnitTest {
+
+    private static final Logger LOG = LoggerFactory.getLogger(JavaTryWithResourcesLongRunningUnitTest.class);
+
+    private static final String TEST_STRING_HELLO_WORLD = "Hello World";
+    private Date resource1Date, resource2Date;
+
+    // tests
+
+    /* Example for using Try_with_resources */
+    @Test
+    public void whenWritingToStringWriter_thenCorrectlyWritten() {
+        final StringWriter sw = new StringWriter();
+        try (PrintWriter pw = new PrintWriter(sw, true)) {
+            pw.print(TEST_STRING_HELLO_WORLD);
+        }
+
+        Assert.assertEquals(sw.getBuffer()
+            .toString(), TEST_STRING_HELLO_WORLD);
+    }
+
+    /* Example for using multiple resources */
+    @Test
+    public void givenStringToScanner_whenWritingToStringWriter_thenCorrectlyWritten() {
+
+        final StringWriter sw = new StringWriter();
+        try (Scanner sc = new Scanner(TEST_STRING_HELLO_WORLD); PrintWriter pw = new PrintWriter(sw, true)) {
+            while (sc.hasNext()) {
+                pw.print(sc.nextLine());
+            }
+        }
+
+        Assert.assertEquals(sw.getBuffer()
+            .toString(), TEST_STRING_HELLO_WORLD);
+    }
+
+    /* Example to show order in which the resources are closed */
+    @Test
+    public void whenFirstAutoClosableResourceIsinitializedFirst_thenFirstAutoClosableResourceIsReleasedFirst() throws Exception {
+        try (AutoCloseableResourcesFirst af = new AutoCloseableResourcesFirst(); AutoCloseableResourcesSecond as = new AutoCloseableResourcesSecond()) {
+            af.doSomething();
+            as.doSomething();
+        }
+        Assert.assertTrue(resource1Date.after(resource2Date));
+    }
+
+    class AutoCloseableResourcesFirst implements AutoCloseable {
+        public AutoCloseableResourcesFirst() {
+            LOG.debug("Constructor -> AutoCloseableResources_First");
+        }
+
+        public void doSomething() {
+            LOG.debug("Something -> AutoCloseableResources_First");
+        }
+
+        @Override
+        public void close() throws Exception {
+            LOG.debug("Closed AutoCloseableResources_First");
+            resource1Date = new Date();
+        }
+    }
+
+    class AutoCloseableResourcesSecond implements AutoCloseable {
+        public AutoCloseableResourcesSecond() {
+            LOG.debug("Constructor -> AutoCloseableResources_Second");
+        }
+
+        public void doSomething() {
+            LOG.debug("Something -> AutoCloseableResources_Second");
+        }
+
+        @Override
+        public void close() throws Exception {
+            LOG.debug("Closed AutoCloseableResources_Second");
+            resource2Date = new Date();
+            Thread.sleep(10000);
+        }
+    }
+
+}

core-java-modules/core-java-exceptions/src/test/java/com/baeldung/optional/PersonRepositoryUnitTest.java

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+package com.baeldung.optional;
+
+import org.junit.Test;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class PersonRepositoryUnitTest {
+
+    PersonRepository personRepository = new PersonRepository();
+
+    @Test
+    public void whenIdIsNull_thenExceptionIsThrown() {
+        assertThrows(IllegalArgumentException.class,
+                () ->
+                        Optional
+                                .ofNullable(personRepository.findNameById(null))
+                                .orElseThrow(IllegalArgumentException::new));
+    }
+
+    @Test
+    public void whenIdIsNonNull_thenNoExceptionIsThrown() {
+        assertAll(
+                () ->
+                        Optional
+                                .ofNullable(personRepository.findNameById("id"))
+                                .orElseThrow(RuntimeException::new));
+    }
+
+    @Test
+    public void whenIdNonNull_thenReturnsNameUpperCase() {
+        String name = Optional
+                .ofNullable(personRepository.findNameById("id"))
+                .map(String::toUpperCase)
+                .orElseThrow(RuntimeException::new);
+
+        assertEquals("NAME", name);
+    }
+
+}