NullPointerException

NullPointerException A NullPointerException is a common runtime exception that occurs when a program attempts to access an object or invoke a method on an object that is null. This error often happens when a variable is not properly initialized or when a method returns null instead of an object. Example: ArrayIndexOutOfBoundsException An ArrayIndexOutOfBoundsException is thrown when attempting to access an array element with an index outside the bounds of the array. This can happen when the index is negative, or when it exceeds the length of the array. Example: Concurrency Issues Java supports multi-threading, which can lead to concurrency issues such as race conditions, deadlocks, and thread interference. These problems occur when multiple threads access shared resources concurrently and interfere with each other’s operations. Example: In the above example, if multiple threads simultaneously call the increment() method on the same Counter object, the count may not be incremented correctly due to race conditions. Memory Leaks Improper memory management can result in memory leaks, where objects are not properly deallocated, leading to increased memory consumption over time. This can happen when objects are not explicitly released or when references to objects are not properly removed. Example: