Error

AI-generated Key Takeaways

• Error is a subclass of Throwable that represents serious problems that applications should not typically try to catch.

• These errors often signify abnormal conditions and are considered unchecked exceptions for compile-time checks.

• Methods are not required to declare Error subclasses in their throws clause.

• Error provides constructors for creating instances with custom messages and causes.

• Developers should address the root cause of Error instances instead of catching them.

public class Error extends Throwable

Known Direct Subclasses AnnotationFormatError, AssertionError, CoderMalfunctionError, FactoryConfigurationError, IOError, LinkageError, ServiceConfigurationError, ThreadDeath, TransformerFactoryConfigurationError, VirtualMachineError AnnotationFormatError Thrown when the annotation parser attempts to read an annotation from a class file and determines that the annotation is malformed.  AssertionError Thrown to indicate that an assertion has failed.  CoderMalfunctionError Error thrown when the decodeLoop method of a CharsetDecoder, or the encodeLoop method of a CharsetEncoder, throws an unexpected exception.  FactoryConfigurationError Thrown when a problem with configuration with the Parser Factories exists.  IOError Thrown when a serious I/O error has occurred.  LinkageError Subclasses of LinkageError indicate that a class has some dependency on another class; however, the latter class has incompatibly changed after the compilation of the former class.  ServiceConfigurationError Error thrown when something goes wrong while loading a service provider.  ThreadDeath An instance of ThreadDeath is thrown in the victim thread when the (deprecated) Thread.stop() method is invoked.  TransformerFactoryConfigurationError Thrown when a problem with configuration with the Transformer Factories exists.  VirtualMachineError Thrown to indicate that the Java Virtual Machine is broken or has run out of resources necessary for it to continue operating.

Known Indirect Subclasses AbstractMethodError, ClassCircularityError, ClassFormatError, ExceptionInInitializerError, GenericSignatureFormatError, IllegalAccessError, IncompatibleClassChangeError, InstantiationError, InternalError, NoClassDefFoundError, NoSuchFieldError, NoSuchMethodError, OutOfMemoryError, StackOverflowError, UnknownError, UnsatisfiedLinkError, UnsupportedClassVersionError, ZipError AbstractMethodError Thrown when an application tries to call an abstract method.  ClassCircularityError Thrown when the Java Virtual Machine detects a circularity in the superclass hierarchy of a class being loaded.  ClassFormatError Thrown when the Java Virtual Machine attempts to read a class file and determines that the file is malformed or otherwise cannot be interpreted as a class file.  ExceptionInInitializerError Signals that an unexpected exception has occurred in a static initializer.  GenericSignatureFormatError Thrown when a syntactically malformed signature attribute is encountered by a reflective method that needs to interpret the generic signature information for a type, method or constructor.  IllegalAccessError Thrown if an application attempts to access or modify a field, or to call a method that it does not have access to.  IncompatibleClassChangeError Thrown when an incompatible class change has occurred to some class definition.  InstantiationError Thrown when an application tries to use the Java new construct to instantiate an abstract class or an interface.  InternalError Thrown to indicate some unexpected internal error has occurred in the Java Virtual Machine.  NoClassDefFoundError Thrown if the Java Virtual Machine or a ClassLoader instance tries to load in the definition of a class (as part of a normal method call or as part of creating a new instance using the new expression) and no definition of the class could be found.  NoSuchFieldError Thrown if an application tries to access or modify a specified field of an object, and that object no longer has that field.  NoSuchMethodError Thrown if an application tries to call a specified method of a class (either static or instance), and that class no longer has a definition of that method.  OutOfMemoryError Thrown when the Java Virtual Machine cannot allocate an object because it is out of memory, and no more memory could be made available by the garbage collector.  StackOverflowError Thrown when a stack overflow occurs because an application recurses too deeply.  UnknownError Thrown when an unknown but serious exception has occurred in the Java Virtual Machine.  UnsatisfiedLinkError Thrown if the Java Virtual Machine cannot find an appropriate native-language definition of a method declared native.  UnsupportedClassVersionError Thrown when the Java Virtual Machine attempts to read a class file and determines that the major and minor version numbers in the file are not supported.  ZipError Signals that an unrecoverable error has occurred.

An Error is a subclass of Throwable that indicates serious problems that a reasonable application should not try to catch. Most such errors are abnormal conditions. The ThreadDeath error, though a "normal" condition, is also a subclass of Error because most applications should not try to catch it.

A method is not required to declare in its throws clause any subclasses of Error that might be thrown during the execution of the method but not caught, since these errors are abnormal conditions that should never occur. That is, Error and its subclasses are regarded as unchecked exceptions for the purposes of compile-time checking of exceptions.

See Also

• ThreadDeath

Public Constructor Summary

	Error() Constructs a new error with null as its detail message.
	Error(String message) Constructs a new error with the specified detail message.
	Error(String message, Throwable cause) Constructs a new error with the specified detail message and cause.
	Error(Throwable cause) Constructs a new error with the specified cause and a detail message of (cause==null ? null : cause.toString()) (which typically contains the class and detail message of cause).

Protected Constructor Summary

Error(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) Constructs a new error with the specified detail message, cause, suppression enabled or disabled, and writable stack trace enabled or disabled.

Inherited Method Summary

From class java.lang.Throwable

synchronized final void	addSuppressed(Throwable exception) Appends the specified exception to the exceptions that were suppressed in order to deliver this exception.
synchronized Throwable	fillInStackTrace() Fills in the execution stack trace.
synchronized Throwable	getCause() Returns the cause of this throwable or null if the cause is nonexistent or unknown.
String	getLocalizedMessage() Creates a localized description of this throwable.
String	getMessage() Returns the detail message string of this throwable.
StackTraceElement[]	getStackTrace() Provides programmatic access to the stack trace information printed by printStackTrace().
synchronized final Throwable[]	getSuppressed() Returns an array containing all of the exceptions that were suppressed, typically by the try-with-resources statement, in order to deliver this exception.
synchronized Throwable	initCause(Throwable cause) Initializes the cause of this throwable to the specified value.
void	printStackTrace() Prints this throwable and its backtrace to the standard error stream.
void	printStackTrace(PrintWriter s) Prints this throwable and its backtrace to the specified print writer.
void	printStackTrace(PrintStream s) Prints this throwable and its backtrace to the specified print stream.
void	setStackTrace(StackTraceElement[] stackTrace) Sets the stack trace elements that will be returned by getStackTrace() and printed by printStackTrace() and related methods.
String	toString() Returns a short description of this throwable.

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

Public Constructors

public Error ()

Constructs a new error with null as its detail message. The cause is not initialized, and may subsequently be initialized by a call to Throwable.initCause(Throwable).

public Error (String message)

Constructs a new error with the specified detail message. The cause is not initialized, and may subsequently be initialized by a call to Throwable.initCause(Throwable).

Parameters

message	the detail message. The detail message is saved for later retrieval by the Throwable.getMessage() method.

public Error (String message, Throwable cause)

Constructs a new error with the specified detail message and cause.

Note that the detail message associated with cause is not automatically incorporated in this error's detail message.

Parameters

message	the detail message (which is saved for later retrieval by the Throwable.getMessage() method).
cause	the cause (which is saved for later retrieval by the Throwable.getCause() method). (A null value is permitted, and indicates that the cause is nonexistent or unknown.)

public Error (Throwable cause)

Constructs a new error with the specified cause and a detail message of (cause==null ? null : cause.toString()) (which typically contains the class and detail message of cause). This constructor is useful for errors that are little more than wrappers for other throwables.

Parameters

cause	the cause (which is saved for later retrieval by the Throwable.getCause() method). (A null value is permitted, and indicates that the cause is nonexistent or unknown.)

Protected Constructors

protected Error (String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace)

Constructs a new error with the specified detail message, cause, suppression enabled or disabled, and writable stack trace enabled or disabled.

Parameters

message	the detail message.
cause	the cause. (A null value is permitted, and indicates that the cause is nonexistent or unknown.)
enableSuppression	whether or not suppression is enabled or disabled
writableStackTrace	whether or not the stack trace should be writable