[BAEL-9555] - Created a core-java-modules folder

core-java-modules/core-java/src/main/java/com/baeldung/.gitignore

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+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear

core-java-modules/core-java/src/main/java/com/baeldung/README.md

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+### Relevant Articles:

core-java-modules/core-java/src/main/java/com/baeldung/abstractclasses/application/Application.java

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+package com.baeldung.abstractclasses.application;
+
+import com.baeldung.abstractclasses.filereaders.BaseFileReader;
+import com.baeldung.abstractclasses.filereaders.LowercaseFileReader;
+import com.baeldung.abstractclasses.filereaders.UppercaseFileReader;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class Application {
+
+    public static void main(String[] args) throws IOException, URISyntaxException {
+
+        Application application = new Application();
+        Path path = application.getPathFromResourcesFile("files/test.txt");
+        BaseFileReader lowercaseFileReader = new LowercaseFileReader(path);
+        lowercaseFileReader.readFile().forEach(line -> System.out.println(line));
+        
+        BaseFileReader uppercaseFileReader = new UppercaseFileReader(path);
+        uppercaseFileReader.readFile().forEach(line -> System.out.println(line));
+
+    }
+    
+    private Path getPathFromResourcesFile(String filePath) throws URISyntaxException {
+        return Paths.get(getClass().getClassLoader().getResource(filePath).toURI());
+         
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/abstractclasses/filereaders/BaseFileReader.java

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+package com.baeldung.abstractclasses.filereaders;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public abstract class BaseFileReader {
+    
+    protected Path filePath;
+    
+    protected BaseFileReader(Path filePath) {
+        this.filePath = filePath;
+    }
+    
+    public Path getFilePath() {
+        return filePath;
+    }
+    
+    public List<String> readFile() throws IOException {
+        return Files.lines(filePath)
+            .map(this::mapFileLine).collect(Collectors.toList());
+    }
+    
+    protected abstract String mapFileLine(String line);
+}

core-java-modules/core-java/src/main/java/com/baeldung/abstractclasses/filereaders/LowercaseFileReader.java

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+package com.baeldung.abstractclasses.filereaders;
+
+import java.nio.file.Path;
+
+public class LowercaseFileReader extends BaseFileReader {
+
+    public LowercaseFileReader(Path filePath) {
+        super(filePath);
+    }
+
+    @Override
+    public String mapFileLine(String line) {
+        return line.toLowerCase();
+    }   
+}

core-java-modules/core-java/src/main/java/com/baeldung/abstractclasses/filereaders/UppercaseFileReader.java

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+package com.baeldung.abstractclasses.filereaders;
+
+import java.nio.file.Path;
+
+public class UppercaseFileReader extends BaseFileReader {
+
+    public UppercaseFileReader(Path filePath) {
+        super(filePath);
+    }
+
+    @Override
+    public String mapFileLine(String line) {
+        return line.toUpperCase();
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/asciiart/AsciiArt.java

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+package com.baeldung.asciiart;
+
+import java.awt.Font;
+import java.awt.Graphics;
+import java.awt.Graphics2D;
+import java.awt.RenderingHints;
+import java.awt.image.BufferedImage;
+
+public class AsciiArt {
+
+    public AsciiArt() {
+    }
+
+    public void drawString(String text, String artChar, Settings settings) {
+        BufferedImage image = getImageIntegerMode(settings.width, settings.height);
+
+        Graphics2D graphics2D = getGraphics2D(image.getGraphics(), settings);
+        graphics2D.drawString(text, 6, ((int) (settings.height * 0.67)));
+
+        for (int y = 0; y < settings.height; y++) {
+            StringBuilder stringBuilder = new StringBuilder();
+
+            for (int x = 0; x < settings.width; x++) {
+                stringBuilder.append(image.getRGB(x, y) == -16777216 ? " " : artChar);
+            }
+
+            if (stringBuilder.toString()
+                .trim()
+                .isEmpty()) {
+                continue;
+            }
+
+            System.out.println(stringBuilder);
+        }
+
+    }
+
+    private BufferedImage getImageIntegerMode(int width, int height) {
+        return new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
+    }
+
+    private Graphics2D getGraphics2D(Graphics graphics, Settings settings) {
+        graphics.setFont(settings.font);
+
+        Graphics2D graphics2D = (Graphics2D) graphics;
+        graphics2D.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+
+        return graphics2D;
+    }
+
+    public class Settings {
+        public Font font;
+        public int width;
+        public int height;
+
+        public Settings(Font font, int width, int height) {
+            this.font = font;
+            this.width = width;
+            this.height = height;
+        }
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/basicsyntax/SimpleAddition.java

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+package com.baeldung.basicsyntax;
+
+public class SimpleAddition {
+
+    public static void main(String[] args) {
+        int a = 10;
+        int b = 5;
+        double c = a + b;
+        System.out.println( a + " + " + b + " = " + c);
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/classloader/CustomClassLoader.java

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+package com.baeldung.classloader;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class CustomClassLoader extends ClassLoader {
+
+    @Override
+    public Class findClass(String name) throws ClassNotFoundException {
+        byte[] b = loadClassFromFile(name);
+        return defineClass(name, b, 0, b.length);
+    }
+
+    private byte[] loadClassFromFile(String fileName)  {
+        InputStream inputStream = getClass().getClassLoader().getResourceAsStream(
+                fileName.replace('.', File.separatorChar) + ".class");
+        byte[] buffer;
+        ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
+        int nextValue = 0;
+        try {
+            while ( (nextValue = inputStream.read()) != -1 ) {
+                byteStream.write(nextValue);
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        buffer = byteStream.toByteArray();
+        return buffer;
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/classloader/PrintClassLoader.java

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+package com.baeldung.classloader;
+
+import com.sun.javafx.util.Logging;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.ArrayList;
+
+public class PrintClassLoader {
+
+    public void printClassLoaders() throws ClassNotFoundException {
+
+        System.out.println("Classloader of this class:" + PrintClassLoader.class.getClassLoader());
+        System.out.println("Classloader of Logging:" + Logging.class.getClassLoader());
+        System.out.println("Classloader of ArrayList:" + ArrayList.class.getClassLoader());
+
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/console/ConsoleConsoleClass.java

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+package com.baeldung.console;
+
+import java.io.Console;
+
+public class ConsoleConsoleClass {
+
+    public static void main(String[] args) {
+        Console console = System.console();
+
+        if (console == null) {
+            System.out.print("No console available");
+            return;
+        }
+
+        String progLanguauge = console.readLine("Enter your favourite programming language: ");
+        console.printf(progLanguauge + " is very interesting!");
+
+        char[] pass = console.readPassword("To finish, enter password: ");
+        
+        if ("BAELDUNG".equals(pass.toString().toUpperCase()))
+            console.printf("Good! Regards!");
+        else 
+            console.printf("Nice try. Regards.");
+
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/console/ConsoleScannerClass.java

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+package com.baeldung.console;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Scanner;
+import java.util.regex.Pattern;
+
+public class ConsoleScannerClass {
+
+    public static void main(String[] args) {
+        System.out.println("Please enter your name and surname: ");
+
+        Scanner scanner = new Scanner(System.in);
+
+        String nameSurname = scanner.nextLine();
+
+        System.out.println("Please enter your gender: ");
+
+        char gender = scanner.next().charAt(0);
+
+        System.out.println("Please enter your age: ");
+
+        int age = scanner.nextInt();
+
+        System.out.println("Please enter your height in meters: ");
+
+        double height = scanner.nextDouble();
+
+        System.out.println(nameSurname + ", " + age + ", is a great " + (gender == 'm' ? "guy" : "girl") + " with " + height + " meters height" + " and " + (gender == 'm' ? "he" : "she") + " reads Baeldung.");
+
+        System.out.print("Have a good");
+        System.out.print(" one!");
+
+        System.out.println("\nPlease enter number of years of experience as a developer: ");
+
+        BufferedReader buffReader = new BufferedReader(new InputStreamReader(System.in));
+
+        int i = 0;
+
+        try {
+            i = Integer.parseInt(buffReader.readLine());
+        } catch (NumberFormatException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        } catch (IOException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
+
+        System.out.println("You are a " + (i > 5 ? "great" : "good") + " developer!");
+
+        int sum = 0, count = 0;
+
+        System.out.println("Please enter your college degrees. To finish, enter baeldung website url");
+
+        while (scanner.hasNextInt()) {
+            int nmbr = scanner.nextInt();
+            sum += nmbr;
+            count++;
+        }
+        int mean = sum / count;
+
+        System.out.println("Your average degree is " + mean);
+
+        if (scanner.hasNext(Pattern.compile("www.baeldung.com")))
+            System.out.println("Correct!");
+        else
+            System.out.println("Baeldung website url is www.baeldung.com");
+
+        if (scanner != null)
+            scanner.close();
+
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/curltojava/JavaCurlExamples.java

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+package com.baeldung.curltojava;
+
+import java.io.BufferedInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class JavaCurlExamples {
+
+    public static String inputStreamToString(InputStream inputStream) {
+        final int bufferSize = 8 * 1024;
+        byte[] buffer = new byte[bufferSize];
+        final StringBuilder builder = new StringBuilder();
+        try (BufferedInputStream bufferedInputStream = new BufferedInputStream(inputStream, bufferSize)) {
+            while (bufferedInputStream.read(buffer) != -1) {
+                builder.append(new String(buffer));
+            }
+        } catch (IOException ex) {
+            Logger.getLogger(JavaCurlExamples.class.getName()).log(Level.SEVERE, null, ex);
+        }
+        return builder.toString();
+    }
+
+    public static void consumeInputStream(InputStream inputStream) {
+        inputStreamToString(inputStream);
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/deserialization/AppleProduct.java

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+package com.baeldung.deserialization;
+
+import java.io.Serializable;
+
+public class AppleProduct implements Serializable {
+
+    private static final long serialVersionUID = 1234567L; // user-defined (i.e. not default or generated)
+    // private static final long serialVersionUID = 7654321L; // user-defined (i.e. not default or generated)
+
+    public String headphonePort;
+    public String thunderboltPort;
+    public String lightningPort;
+
+    public String getHeadphonePort() {
+        return headphonePort;
+    }
+
+    public String getThunderboltPort() {
+        return thunderboltPort;
+    }
+
+    public static long getSerialVersionUID() {
+        return serialVersionUID;
+    }
+
+    public String getLightningPort() {
+        return lightningPort;
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/deserialization/DeserializationUtility.java

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+package com.baeldung.deserialization;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.util.Base64;
+
+public class DeserializationUtility {
+
+    public static void main(String[] args) throws ClassNotFoundException, IOException {
+
+        String serializedObj = "rO0ABXNyACljb20uYmFlbGR1bmcuZGVzZXJpYWxpemF0aW9uLkFwcGxlUHJvZHVjdAAAAAAAEtaHAgADTAANaGVhZHBob25lUG9ydHQAEkxqYXZhL2xhbmcvU3RyaW5nO0wADWxpZ2h0bmluZ1BvcnRxAH4AAUwAD3RodW5kZXJib2x0UG9ydHEAfgABeHB0ABFoZWFkcGhvbmVQb3J0MjAyMHQAEWxpZ2h0bmluZ1BvcnQyMDIwdAATdGh1bmRlcmJvbHRQb3J0MjAyMA==";
+        System.out.println("Deserializing AppleProduct...");
+        AppleProduct deserializedObj = (AppleProduct) deSerializeObjectFromString(serializedObj);
+        System.out.println("Headphone port of AppleProduct:" + deserializedObj.getHeadphonePort());
+        System.out.println("Thunderbolt port of AppleProduct:" + deserializedObj.getThunderboltPort());
+        System.out.println("LightningPort port of AppleProduct:" + deserializedObj.getLightningPort());
+    }
+
+    public static Object deSerializeObjectFromString(String s) throws IOException, ClassNotFoundException {
+        byte[] data = Base64.getDecoder().decode(s);
+        ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(data));
+        Object o = ois.readObject();
+        ois.close();
+        return o;
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/deserialization/SerializationUtility.java

@@ -0,0 +1,31 @@
+package com.baeldung.deserialization;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+import java.util.Base64;
+
+public class SerializationUtility {
+
+    public static void main(String[] args) throws ClassNotFoundException, IOException {
+
+        AppleProduct macBook = new AppleProduct();
+        macBook.headphonePort = "headphonePort2020";
+        macBook.thunderboltPort = "thunderboltPort2020";
+        macBook.lightningPort = "lightningPort2020";
+
+        String serializedObj = serializeObjectToString(macBook);
+        System.out.println("Serialized AppleProduct object to string:");
+        System.out.println(serializedObj);
+    }
+
+    public static String serializeObjectToString(Serializable o) throws IOException {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ObjectOutputStream oos = new ObjectOutputStream(baos);
+        oos.writeObject(o);
+        oos.close();
+        return Base64.getEncoder().encodeToString(baos.toByteArray());
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/encoding/CharacterEncodingExamples.java

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+package com.baeldung.encoding;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.UnsupportedEncodingException;
+
+public class CharacterEncodingExamples {
+
+    static String readFile(String filePath, String encoding) throws IOException {
+        File file = new File(filePath);
+        StringBuffer buffer = new StringBuffer();
+        try (InputStreamReader isr = new InputStreamReader(new FileInputStream(file), encoding)) {
+            int data;
+            while ((data = isr.read()) != -1) {
+                buffer.append((char) data);
+            }
+        }
+        return buffer.toString();
+    }
+
+    static String convertToBinary(String input, String encoding) throws UnsupportedEncodingException {
+        byte[] bytes = input.getBytes(encoding);
+        StringBuffer buffer = new StringBuffer();
+        for (int b : bytes) {
+            buffer.append(Integer.toBinaryString((b + 256) % 256));
+            buffer.append(" ");
+        }
+        return buffer.toString();
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/Arithmetic.java

@@ -0,0 +1,20 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class Arithmetic {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(Arithmetic.class);
+
+    public static void main(String[] args) {
+
+        try {
+            int result = 30 / 0; // Trying to divide by zero
+        } catch (ArithmeticException e) {
+            LOGGER.error("ArithmeticException caught!");
+        }
+
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/ArrayIndexOutOfBounds.java

@@ -0,0 +1,24 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ArrayIndexOutOfBounds {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(ArrayIndexOutOfBounds.class);
+
+    public static void main(String[] args) {
+
+        int[] nums = new int[] { 1, 2, 3 };
+
+        try {
+            int numFromNegativeIndex = nums[-1]; // Trying to access at negative index
+            int numFromGreaterIndex = nums[4]; // Trying to access at greater index
+            int numFromLengthIndex = nums[3]; // Trying to access at index equal to size of the array
+        } catch (ArrayIndexOutOfBoundsException e) {
+            LOGGER.error("ArrayIndexOutOfBoundsException caught");
+        }
+
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/ClassCast.java

@@ -0,0 +1,36 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class Animal {
+
+}
+
+class Dog extends Animal {
+
+}
+
+class Lion extends Animal {
+
+}
+
+public class ClassCast {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(ClassCast.class);
+
+    public static void main(String[] args) {
+
+        try {
+            Animal animalOne = new Dog(); // At runtime the instance is dog
+            Dog bruno = (Dog) animalOne; // Downcasting
+
+            Animal animalTwo = new Lion(); // At runtime the instance is animal
+            Dog tommy = (Dog) animalTwo; // Downcasting
+        } catch (ClassCastException e) {
+            LOGGER.error("ClassCastException caught!");
+        }
+
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/FileNotFound.java

@@ -0,0 +1,25 @@
+package com.baeldung.exceptions;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class FileNotFound {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(FileNotFound.class);
+    
+    public static void main(String[] args) {
+        
+        BufferedReader reader = null;
+        try {
+            reader = new BufferedReader(new FileReader(new File("/invalid/file/location")));
+        } catch (FileNotFoundException e) {
+            LOGGER.error("FileNotFoundException caught!");
+        }
+    }
+    
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/GlobalExceptionHandler.java

@@ -0,0 +1,28 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class GlobalExceptionHandler {
+
+    public static void main(String[] args) {
+
+        Handler globalExceptionHandler = new Handler();
+        Thread.setDefaultUncaughtExceptionHandler(globalExceptionHandler);
+        new GlobalExceptionHandler().performArithmeticOperation(10, 0);
+    }
+
+    public int performArithmeticOperation(int num1, int num2) {
+        return num1/num2;
+    }
+
+}
+
+class Handler implements Thread.UncaughtExceptionHandler {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(Handler.class);
+
+    public void uncaughtException(Thread t, Throwable e) {
+        LOGGER.info("Unhandled exception caught!");
+    }
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/IllegalArgument.java

@@ -0,0 +1,18 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class IllegalArgument {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(IllegalArgument.class);
+
+    public static void main(String[] args) {
+        try {
+            Thread.sleep(-1000);
+        } catch (InterruptedException e) {
+            LOGGER.error("IllegalArgumentException caught!");
+        }
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/IllegalState.java

@@ -0,0 +1,32 @@
+package com.baeldung.exceptions;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class IllegalState {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(IllegalState.class);
+
+    public static void main(String[] args) {
+
+        List<Integer> intList = new ArrayList<>();
+
+        for (int i = 0; i < 10; i++) {
+            intList.add(i);
+        }
+
+        Iterator<Integer> intListIterator = intList.iterator(); // Initialized with index at -1
+
+        try {
+            intListIterator.remove(); // IllegalStateException
+        } catch (IllegalStateException e) {
+            LOGGER.error("IllegalStateException caught!");
+        }
+
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/InterruptedExceptionExample.java

@@ -0,0 +1,28 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+class ChildThread extends Thread {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(ChildThread.class);
+
+    public void run() {
+        try {
+            Thread.sleep(1000);
+        } catch (InterruptedException e) {
+            LOGGER.error("InterruptedException caught!");
+        }
+    }
+    
+}
+
+public class InterruptedExceptionExample {
+
+    public static void main(String[] args) throws InterruptedException {
+        ChildThread childThread = new ChildThread();
+        childThread.start();
+        childThread.interrupt();
+    }
+    
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/MalformedURL.java

@@ -0,0 +1,25 @@
+package com.baeldung.exceptions;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class MalformedURL {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(MalformedURL.class);
+
+    public static void main(String[] args) {
+
+        URL baeldungURL = null;
+
+        try {
+            baeldungURL = new URL("malformedurl");
+        } catch (MalformedURLException e) {
+            LOGGER.error("MalformedURLException caught!");
+        }
+
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/NullPointer.java

@@ -0,0 +1,36 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class NullPointer {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(NullPointer.class);
+
+    public static void main(String[] args) {
+
+        Person personObj = null;
+
+        try {
+            String name = personObj.personName; // Accessing the field of a null object
+            personObj.personName = "Jon Doe"; // Modifying the field of a null object
+        } catch (NullPointerException e) {
+            LOGGER.error("NullPointerException caught!");
+        }
+
+    }
+}
+
+class Person {
+
+    public String personName;
+
+    public String getPersonName() {
+        return personName;
+    }
+
+    public void setPersonName(String personName) {
+        this.personName = personName;
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/NumberFormat.java

@@ -0,0 +1,23 @@
+package com.baeldung.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class NumberFormat {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(NumberFormat.class);
+
+    public static void main(String[] args) {
+
+        String str1 = "100ABCD";
+
+        try {
+            int x = Integer.parseInt(str1); // Converting string with inappropriate format
+            int y = Integer.valueOf(str1);
+        } catch (NumberFormatException e) {
+            LOGGER.error("NumberFormatException caught!");
+        }
+
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/ParseExceptionExample.java

@@ -0,0 +1,25 @@
+package com.baeldung.exceptions;
+
+import java.text.DateFormat;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ParseExceptionExample {
+
+    private static Logger LOGGER = LoggerFactory.getLogger(ParseExceptionExample.class);
+
+    public static void main(String[] args) {
+
+        DateFormat format = new SimpleDateFormat("MM, dd, yyyy");
+
+        try {
+            format.parse("01, , 2010");
+        } catch (ParseException e) {
+            LOGGER.error("ParseException caught!");
+        }
+    }
+
+}

core-java-modules/core-java/src/main/java/com/baeldung/exceptions/StackTraceToString.java

@@ -0,0 +1,30 @@
+package com.baeldung.exceptions;
+
+import org.apache.commons.lang3.exception.ExceptionUtils;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+public class StackTraceToString {
+
+    public static void main(String[] args) {
+        // Convert a StackTrace to String using core java
+        try {
+            throw new NullPointerException();
+        } catch (Exception e) {
+            StringWriter sw = new StringWriter();
+            PrintWriter pw = new PrintWriter(sw);
+            e.printStackTrace(pw);
+
+            System.out.println(sw.toString());
+        }
+
+        // Convert a StackTrace to String using Apache Commons
+        try {
+            throw new IndexOutOfBoundsException();
+        } catch (Exception e) {
+            System.out.println(ExceptionUtils.getStackTrace(e));
+        }
+    }
+
+}