🚀 Java programming language | Buggy code🤯
Welcome to your programming channel 👋🏻. Today we are talking about the buggy code in Java. So if you want to know more about this topic, stay with me until the end of this education.
1.BufferOverflowError: Array length too small
public class BufferOverflowErrorExample {
public static void main(String[] args) {
int[] intArray = new int[5];
for (int i = 0; i <= intArray.length; i++) {
intArray[i] = i * 2;
}
}
}This code will cause a BufferOverflowError because the array index (i) goes out of bounds when it reaches the value of intArray.length.
2.ArrayIndexOutOfBoundsException: Array length too small
public class ArrayIndexOutOfBoundsExceptionExample {
public static void main(String[] args) {
int[] intArray = new int[5];
for (int i = 0; i < intArray.length + 1; i++) {
intArray[i] = i * 2;
}
}
}This code will throw an ArrayIndexOutOfBoundsException because the array index (i) goes out of bounds when it reaches the value of intArray.length + 1.
3.NullPointerException: Null array reference
public class NullPointerExceptionExample {
public static void main(String[] args) {
int[] intArray = null;
for (int i = 0; i < intArray.length; i++) {
intArray[i] = i * 2;
}
}
}This code will throw a NullPointerException because it tries to access a method (length) of a null array reference (intArray).
4.ConcurrentModificationException: Iterator.remove()
import java.util.ArrayList;
import java.util.Iterator;
public class ConcurrentModificationExceptionExample {
public static void main(String[] args) {
ArrayList<Integer> intList = new ArrayList<>();
intList.add(1);
intList.add(2);
intList.add(3);
intList.add(4);
intList.add(5);
Iterator<Integer> iterator = intList.iterator();
while (iterator.hasNext()) {
iterator.next();
iterator.remove();
}
}
}This code will throw a ConcurrentModificationException because it attempts to remove elements from the list while iterating over it.
5.NoSuchMethodError: Undefined method
public class NoSuchMethodErrorExample {
public static void main(String[] args) {
int[] intArray = new int[5];
intArray.sort(); // No such method in int[]. This method is present in List.
}
}This code will throw a NoSuchMethodError because it calls the sort() method on an array (intArray). The sort() method is undefined for arrays and is available only for Lists.
6.OutOfMemoryError: Exhausted heap memory
public class OutOfMemoryErrorExample {
public static void main(String[] args) {
ArrayList<String> stringList = new ArrayList<>();
String testString = "Test string";
while (true) {
stringList.add(testString);
}
}
}This code will throw an OutOfMemoryError because it keeps adding strings to the list (stringList) without ever freeing up memory. The Java heap space will become full, causing the OutOfMemoryError.
7.ClassNotFoundException: Undefined class
public class ClassNotFoundExceptionExample {
public static void main(String[] args) {
try {
Class<?> cls = Class.forName("com.example.UndefinedClass");
} catch (ClassNotFoundException e) {
System.out.println("ClassNotFoundException: " + e.getMessage());
}
}
}This code will throw a ClassNotFoundException because it tries to load a class (com.example.UndefinedClass) that has not been defined.
8.UnsupportedOperationException: Unsupported operation
import java.util.Collections;
import java.util.List;
public class UnsupportedOperationExceptionExample {
public static void main(String[] args) {
List<String> unmodifiableList = Collections.unmodifiableList(new ArrayList<>());
unmodifiableList.add("Test string"); // Unsupported operation
}
}This code will throw an UnsupportedOperationException because it tries to add a string to an unmodifiable list (unmodifiableList). Unmodifiable lists do not support addition, deletion, or modification operations.
9.NumberFormatException: Invalid format for integer parsing
public class NumberFormatExceptionExample {
public static void main(String[] args) {
String invalidNumber = "1234a";
try {
int intNumber = Integer.parseInt(invalidNumber);
} catch (NumberFormatException e) {
System.out.println("NumberFormatException: " + e.getMessage());
}
}
}This code will throw a NumberFormatException because it tries to parse an invalid number (1234a) as an integer. The Integer.parseInt() method can only parse strings that represent valid integers.
10.IOException: Error while reading/writing from/to a file
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class IOExceptionExample {
public static void main(String[] args) {
try {
FileInputStream inputStream = new FileInputStream("input.txt");
FileOutputStream outputStream = new FileOutputStream("output.txt");
int data;
while ((data = inputStream.read()) != -1) {
outputStream.write(data);
}
inputStream.close();
outputStream.close();
} catch (IOException e) {
System.out.println("IOException: " + e.getMessage());
}
}
}This code will throw an IOException if an error occurs while reading from the file (input.txt) or writing to the file (output.txt). Common reasons for this exception include file not found, insufficient permissions, or disk full.
