| Error/Exception | Description | Common Causes |
|---|---|---|
| ArithmeticException | Thrown when an exceptional arithmetic condition occurs, such as division by zero. | Dividing by zero or attempting illegal mathematical operations. |
| ArrayIndexOutOfBoundsException | Thrown when an array is accessed with an illegal index. | Accessing an array index that is out of its bounds. |
| ClassNotFoundException | Thrown when an application tries to load a class that is not found. | Missing or incorrect classpath or class file missing in the project. |
| NullPointerException | Thrown when the JVM attempts to access a method or field on a null object reference. | Dereferencing a null reference or calling methods on null objects. |
| NumberFormatException | Thrown when an attempt is made to convert a string to a numeric type, but the string is not a valid number. | Trying to convert a non-numeric string to an integer or other numeric type. |
| IllegalArgumentException | Thrown when a method receives an illegal or inappropriate argument. | Passing an argument that doesn’t meet method requirements or constraints. |
| FileNotFoundException | Thrown when an attempt to open the file denoted by a specified pathname fails. | Specified file doesn’t exist, or the path is incorrect. |
| IOException | Thrown when an I/O operation fails or is interrupted. | File I/O errors, network errors, or improper stream handling. |
| IndexOutOfBoundsException | Thrown when an index of some sort (like for a list or string) is out of range. | Attempting to access a list or string index that is outside the valid range. |
| OutOfMemoryError | Thrown when the JVM runs out of memory. | Insufficient memory due to large data structures or memory leaks. |
| StackOverflowError | Thrown when the stack of the JVM exceeds its limit. | Infinite recursion or too many nested method calls. |
| NoClassDefFoundError | Thrown when a class definition could not be found during runtime. | Classpath issues or missing classes at runtime, even though they were available during compilation. |
| SecurityException | Thrown when a security manager denies an access control operation. | Security manager prevents access to a restricted resource or operation. |
| UnsupportedOperationException | Thrown to indicate that the requested operation is not supported. | Trying to use an unsupported method or operation on a collection or interface. |
| ConcurrentModificationException | Thrown when a collection is modified while it is being iterated over. | Modifying a collection while using an iterator. |
| ClassCastException | Thrown when an object is cast to a type of which it is not an instance. | Incorrect casting between incompatible types. |
| TimeoutException | Thrown when a blocking operation times out. | Network operations or tasks that take longer than expected. |
| IllegalStateException | Thrown when a method is invoked at an illegal or inappropriate time. | Calling a method in the wrong state of an object, like calling next() on an empty iterator. |
| AssertionError | Thrown when an assertion fails. | assert statement fails. |
| InterruptedException | Thrown when a thread is interrupted while it is waiting, sleeping, or otherwise occupied. | When a thread is interrupted during a blocking operation like sleep(). |
| NoSuchMethodException | Thrown when a particular method cannot be found. | Incorrect method name, argument types, or inaccessible methods due to visibility. |
| NoSuchFieldException | Thrown when a particular field cannot be found. | Incorrect field name or inaccessible fields due to visibility. |
| IllegalAccessException | Thrown when an application tries to reflectively access a method or field but doesn’t have access to it. | Trying to access a method or field that is private or protected without proper access privileges. |
| InstantiationException | Thrown when an application tries to instantiate an abstract class or an interface. | Attempting to instantiate an abstract class or interface. |
| CloneNotSupportedException | Thrown when the clone() method is called on an object that doesn’t implement Cloneable. |
Attempting to clone an object that doesn’t support cloning. |
| NegativeArraySizeException | Thrown when an attempt is made to create an array with a negative size. | Trying to create an array with a size less than zero. |
| TooManyListenersException | Thrown when an attempt is made to add more than one listener to an event source that doesn’t allow it. | Adding multiple listeners when only one is allowed. |
| UnsupportedEncodingException | Thrown when a particular character encoding is not supported. | Using an unsupported character encoding type in I/O operations. |
| ResourceException | Thrown when a resource fails, such as a network failure. | Error in accessing a network or database resource. |
| MalformedURLException | Thrown when a URL is invalid or malformed. | Incorrect URL format, such as missing protocol or an invalid URL structure. |
| SQLException | Thrown when there is an error in database access. | Database connection failure, syntax error in SQL, or invalid query. |
| UnsupportedFileSystemException | Thrown when an unsupported file system operation is attempted. | Trying to use file system operations unsupported by the operating system. |
| ConnectException | Thrown when a connection is refused or fails. | Attempting to connect to a service that is unavailable or refuses the connection. |
| SocketTimeoutException | Thrown when a socket connection times out. | Connection delay or timeout due to network issues. |
| UnknownHostException | Thrown when the IP address of a host could not be determined. | Specified host could not be resolved by DNS. |
| java.lang.OutOfMemoryError | Thrown when the JVM runs out of memory. | Memory leaks or insufficient memory allocation for the program. |
| java.lang.UnsupportedClassVersionError | Thrown when a class was compiled with a higher version of Java than the JVM can handle. | Class was compiled with a newer Java version than the current runtime environment. |
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