Java Code Common Problems
- NullPointerException (NPE): This is one of the most common runtime exceptions in Java. It occurs when you try to access or invoke methods on an object reference that is null.
2. ConcurrentModificationException: This exception is thrown when you try to modify a collection (like ArrayList, HashMap, etc.) while iterating over it using an iterator, without using the iterator’s own methods to modify it.
3. ClassCastException: This exception is thrown when you try to cast an object of one class to another class, but the actual object is not an instance of the target class or one of its subclasses.
4. OutOfMemoryError: This error occurs when the Java Virtual Machine (JVM) runs out of memory, usually due to memory leaks or inefficient memory usage.
5. StackOverflowError: This error occurs when the call stack exceeds its limit, typically due to infinite recursion or deep recursion without a proper base case.
6. NumberFormatException: This exception is thrown when you try to convert a string into a numeric format (like int or double), but the string does not contain a valid numeric value.
7. ArrayIndexOutOfBoundsException: This exception occurs when you try to access an array element with an index that is either negative or greater than or equal to the length of the array.