Throwable

Throwable

The TooManyListenersException Exception is used as part of the Java Event model to annotate and implement a unicast special case of a multicast Event Source. TransactionTooLargeException The Binder transaction failed because it was too large. TransformerConfigurationException Indicates a serious configuration error. TransformerException This class specifies an exceptional condition that occurred during the transformation process. TransformerFactoryConfigurationError Thrown when a problem with configuration with the Transformer Factories exists. TypeNotPresentException Thrown when an application tries to access a type using a string representing the type's name, but no definition for the type with the specified name can be found. URISyntaxException Checked exception thrown to indicate that a string could not be parsed as a URI reference. UTFDataFormatException Signals that a malformed string in modified UTF-8 format has been read in a data input stream or by any class that implements the data input interface. UnbufferedIoViolation See #Builder.detectUnbufferedIo() UncheckedIOException Wraps an IOException with an unchecked exception. UndeclaredThrowableException Thrown by a method invocation on a proxy instance if its invocation handler's invoke method throws a checked exception (a Throwable that is not assignable to RuntimeException or Error) that is not assignable to any of the exception types declared in the throws clause of the method that was invoked on the proxy instance and dispatched to the invocation handler. UnknownAuthenticationKeyException Thrown if trying to certify an unknown dynamic authentication key. UnknownError Thrown when an unknown but serious exception has occurred in the Java Virtual Machine. UnknownFormatConversionException Unchecked exception thrown when an unknown conversion is given. UnknownFormatFlagsException Unchecked exception thrown when an unknown flag is given. UnknownHostException Thrown to indicate that the IP address of a host could not be determined. UnknownServiceException Thrown to indicate that an unknown service exception has occurred. UnmappableCharacterException Checked exception thrown when an input character (or byte) sequence is valid but cannot be mapped to an output byte (or character) sequence. UnrecoverableEntryException This exception is thrown if an entry in the keystore cannot be recovered. UnrecoverableKeyException This exception is thrown if a key in the keystore cannot be recovered. UnresolvedAddressException Unchecked exception thrown when an attempt is made to invoke a network operation upon an unresolved socket address. UnsafeIntentLaunchViolation Violation raised when your app launches an Intent which originated from outside your app. UnsafeStateException Exception thrown when a DevicePolicyManager operation failed because it was not safe to be executed at that moment. UnsatisfiedLinkError Thrown if the Java Virtual Machine cannot find an appropriate native-language definition of a method declared native. UnsupportedAddressTypeException Unchecked exception thrown when an attempt is made to bind or connect to a socket address of a type that is not supported. UnsupportedCallbackException Signals that a CallbackHandler does not recognize a particular Callback. UnsupportedCharsetException Unchecked exception thrown when no support is available for a requested charset. 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. UnsupportedEncodingException The Character Encoding is not supported. UnsupportedOperationException Thrown to indicate that the requested operation is not supported. UnsupportedSchemeException Exception thrown when an attempt is made to construct a MediaDrm object using a crypto scheme UUID that is not supported by the device UnsupportedTemporalTypeException UnsupportedTemporalTypeException indicates that a ChronoField or ChronoUnit is not supported for a Temporal class. UntaggedSocketViolation UserManager.UserOperationException Thrown to indicate user operation failed. UserNotAuthenticatedException Indicates that a cryptographic operation could not be performed because the user has not been authenticated recently enough. UserPresenceUnavailableException Indicates the condition that a proof of user-presence was requested but this proof was not presented. UserPrincipalNotFoundException Checked exception thrown when a lookup of UserPrincipal fails because the principal does not exist. VerifyError Thrown when the "verifier" detects that a class file, though well formed, contains some sort of internal inconsistency or security problem. VirtualMachineError Thrown to indicate that the Java Virtual Machine is broken or has run out of resources necessary for it to continue operating. WebViewMethodCalledOnWrongThreadViolation WindowManager.BadTokenException Exception that is thrown when trying to add view whose LayoutParams LayoutParams.token is invalid. WindowManager.InvalidDisplayException Exception that is thrown when calling ViewManager.addView(View, LayoutParams) to a secondary display that cannot be found. WriteAbortedException Signals that one of the ObjectStreamExceptions was thrown during a write operation. WritePendingException Unchecked exception thrown when an attempt is made to write to an asynchronous socket channel and a previous write has not completed. WrongMethodTypeException Thrown to indicate that code has attempted to call a method handle via the wrong method type. WrongThreadException Thrown to indicate that a method has been called on the wrong thread. XPathException XPathException represents a generic XPath exception. XPathExpressionException XPathExpressionException represents an error in an XPath expression. XPathFactoryConfigurationException XPathFactoryConfigurationException represents a configuration error in a XPathFactory environment. XPathFunctionException XPathFunctionException represents an error with an XPath function. XmlPullParserException This exception is thrown to signal XML Pull Parser related faults. ZipError Signals that an unrecoverable error has occurred. ZipException Signals that a Zip exception of some sort has occurred. ZoneRulesException Thrown to indicate a problem with time-zone configuration.

The Throwable class is the superclass of all errors and exceptions in the Java language. Only objects that are instances of this class (or one of its subclasses) are thrown by the Java Virtual Machine or can be thrown by the Java throw statement. Similarly, only this class or one of its subclasses can be the argument type in a catch clause. For the purposes of compile-time checking of exceptions, Throwable and any subclass of Throwable that is not also a subclass of either RuntimeException or Error are regarded as checked exceptions.

Instances of two subclasses, Error and Exception, are conventionally used to indicate that exceptional situations have occurred. Typically, these instances are freshly created in the context of the exceptional situation so as to include relevant information (such as stack trace data).

A throwable contains a snapshot of the execution stack of its thread at the time it was created. It can also contain a message string that gives more information about the error. Over time, a throwable can suppress other throwables from being propagated. Finally, the throwable can also contain a cause: another throwable that caused this throwable to be constructed. The recording of this causal information is referred to as the chained exception facility, as the cause can, itself, have a cause, and so on, leading to a "chain" of exceptions, each caused by another.

One reason that a throwable may have a cause is that the class that throws it is built atop a lower layered abstraction, and an operation on the upper layer fails due to a failure in the lower layer. It would be bad design to let the throwable thrown by the lower layer propagate outward, as it is generally unrelated to the abstraction provided by the upper layer. Further, doing so would tie the API of the upper layer to the details of its implementation, assuming the lower layer's exception was a checked exception. Throwing a "wrapped exception" (i.e., an exception containing a cause) allows the upper layer to communicate the details of the failure to its caller without incurring either of these shortcomings. It preserves the flexibility to change the implementation of the upper layer without changing its API (in particular, the set of exceptions thrown by its methods).

A second reason that a throwable may have a cause is that the method that throws it must conform to a general-purpose interface that does not permit the method to throw the cause directly. For example, suppose a persistent collection conforms to the Collection interface, and that its persistence is implemented atop java.io. Suppose the internals of the add method can throw an IOException. The implementation can communicate the details of the IOException to its caller while conforming to the Collection interface by wrapping the IOException in an appropriate unchecked exception. (The specification for the persistent collection should indicate that it is capable of throwing such exceptions.)

A cause can be associated with a throwable in two ways: via a constructor that takes the cause as an argument, or via the initCause(Throwable) method. New throwable classes that wish to allow causes to be associated with them should provide constructors that take a cause and delegate (perhaps indirectly) to one of the Throwable constructors that takes a cause. Because the initCause method is public, it allows a cause to be associated with any throwable, even a "legacy throwable" whose implementation predates the addition of the exception chaining mechanism to Throwable.

By convention, class Throwable and its subclasses have two constructors, one that takes no arguments and one that takes a String argument that can be used to produce a detail message. Further, those subclasses that might likely have a cause associated with them should have two more constructors, one that takes a Throwable (the cause), and one that takes a String (the detail message) and a Throwable (the cause).

Summary

Public constructors

Protected constructors

Public constructors
`Throwable()` Constructs a new throwable with `null` as its detail message.
`Throwable(String message)` Constructs a new throwable with the specified detail message.
`Throwable(String message, Throwable cause)` Constructs a new throwable with the specified detail message and cause.
`Throwable(Throwable cause)` Constructs a new throwable 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 constructors
`Throwable(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace)` Constructs a new throwable with the specified detail message, cause, suppression enabled or disabled, and writable stack trace enabled or disabled.

Public methods
`final void`	`addSuppressed(Throwable exception)` Appends the specified exception to the exceptions that were suppressed in order to deliver this exception.
`Throwable`	`fillInStackTrace()` Fills in the execution stack trace.
`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()`.
`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.
`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.

Parameters
`message`	`String`: the detail message. The detail message is saved for later retrieval by the `getMessage()` method.

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

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

Added in API level 19

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

Constructs a new throwable with the specified detail message, cause, suppression enabled or disabled, and writable stack trace enabled or disabled. If suppression is disabled, getSuppressed() for this object will return a zero-length array and calls to addSuppressed(Throwable) that would otherwise append an exception to the suppressed list will have no effect. If the writable stack trace is false, this constructor will not call fillInStackTrace(), a null will be written to the stackTrace field, and subsequent calls to fillInStackTrace and setStackTrace(StackTraceElement[]) will not set the stack trace. If the writable stack trace is false, getStackTrace() will return a zero length array.

Note that the other constructors of Throwable treat suppression as being enabled and the stack trace as being writable. Subclasses of Throwable should document any conditions under which suppression is disabled and document conditions under which the stack trace is not writable. Disabling of suppression should only occur in exceptional circumstances where special requirements exist, such as a virtual machine reusing exception objects under low-memory situations. Circumstances where a given exception object is repeatedly caught and rethrown, such as to implement control flow between two sub-systems, is another situation where immutable throwable objects would be appropriate.

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

See also:

Public methods

addSuppressed

Added in API level 19

public final void addSuppressed (Throwable exception)

Appends the specified exception to the exceptions that were suppressed in order to deliver this exception. This method is thread-safe and typically called (automatically and implicitly) by the try-with-resources statement.

The suppression behavior is enabled unless disabled via a constructor. When suppression is disabled, this method does nothing other than to validate its argument.

Note that when one exception causes another exception, the first exception is usually caught and then the second exception is thrown in response. In other words, there is a causal connection between the two exceptions. In contrast, there are situations where two independent exceptions can be thrown in sibling code blocks, in particular in the try block of a try-with-resources statement and the compiler-generated finally block which closes the resource. In these situations, only one of the thrown exceptions can be propagated. In the try-with-resources statement, when there are two such exceptions, the exception originating from the try block is propagated and the exception from the finally block is added to the list of exceptions suppressed by the exception from the try block. As an exception unwinds the stack, it can accumulate multiple suppressed exceptions.

An exception may have suppressed exceptions while also being caused by another exception. Whether or not an exception has a cause is semantically known at the time of its creation, unlike whether or not an exception will suppress other exceptions which is typically only determined after an exception is thrown.

Note that programmer written code is also able to take advantage of calling this method in situations where there are multiple sibling exceptions and only one can be propagated.

Parameters
`exception`	`Throwable`: the exception to be added to the list of suppressed exceptions

Throws
`IllegalArgumentException`	if `exception` is this throwable; a throwable cannot suppress itself.
`NullPointerException`	if `exception` is `null`

Returns
`Throwable`	a reference to this `Throwable` instance.

Returns
`Throwable`	the cause of this throwable or `null` if the cause is nonexistent or unknown.

Returns
`String`	The localized description of this throwable.

Returns
`String`	the detail message string of this `Throwable` instance (which may be `null`).

Returns
`StackTraceElement[]`	an array of stack trace elements representing the stack trace pertaining to this throwable.

Returns
`Throwable[]`	an array containing all of the exceptions that were suppressed to deliver this exception.

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

Returns
`Throwable`	a reference to this `Throwable` instance.

Throws
`IllegalArgumentException`	if `cause` is this throwable. (A throwable cannot be its own cause.)
`IllegalStateException`	if this throwable was created with `Throwable(Throwable)` or `Throwable(String,Throwable)`, or this method has already been called on this throwable.

printStackTrace

Added in API level 1

public void printStackTrace ()

Prints this throwable and its backtrace to the standard error stream. This method prints a stack trace for this Throwable object on the error output stream that is the value of the field System.err. The first line of output contains the result of the toString() method for this object. Remaining lines represent data previously recorded by the method fillInStackTrace(). The format of this information depends on the implementation, but the following example may be regarded as typical:

 java.lang.NullPointerException
         at MyClass.mash(MyClass.java:9)
         at MyClass.crunch(MyClass.java:6)
         at MyClass.main(MyClass.java:3)

This example was produced by running the program:

 class MyClass {
     public static void main(String[] args) {
         crunch(null);
     }
     static void crunch(int[] a) {
         mash(a);
     }
     static void mash(int[] b) {
         System.out.println(b[0]);
     }
 }

The backtrace for a throwable with an initialized, non-null cause should generally include the backtrace for the cause. The format of this information depends on the implementation, but the following example may be regarded as typical:

 HighLevelException: MidLevelException: LowLevelException
         at Junk.a(Junk.java:13)
         at Junk.main(Junk.java:4)
 Caused by: MidLevelException: LowLevelException
         at Junk.c(Junk.java:23)
         at Junk.b(Junk.java:17)
         at Junk.a(Junk.java:11)
         ... 1 more
 Caused by: LowLevelException
         at Junk.e(Junk.java:30)
         at Junk.d(Junk.java:27)
         at Junk.c(Junk.java:21)
         ... 3 more

Note the presence of lines containing the characters "...". These lines indicate that the remainder of the stack trace for this exception matches the indicated number of frames from the bottom of the stack trace of the exception that was caused by this exception (the "enclosing" exception). This shorthand can greatly reduce the length of the output in the common case where a wrapped exception is thrown from same method as the "causative exception" is caught. The above example was produced by running the program:

 public class Junk {
     public static void main(String args[]) {
         try {
             a();
         } catch(HighLevelException e) {
             e.printStackTrace();
         }
     }
     static void a() throws HighLevelException {
         try {
             b();
         } catch(MidLevelException e) {
             throw new HighLevelException(e);
         }
     }
     static void b() throws MidLevelException {
         c();
     }
     static void c() throws MidLevelException {
         try {
             d();
         } catch(LowLevelException e) {
             throw new MidLevelException(e);
         }
     }
     static void d() throws LowLevelException {
        e();
     }
     static void e() throws LowLevelException {
         throw new LowLevelException();
     }
 }

 class HighLevelException extends Exception {
     HighLevelException(Throwable cause) { super(cause); }
 }

 class MidLevelException extends Exception {
     MidLevelException(Throwable cause)  { super(cause); }
 }

 class LowLevelException extends Exception {
 }

As of release 7, the platform supports the notion of suppressed exceptions (in conjunction with the try-with-resources statement). Any exceptions that were suppressed in order to deliver an exception are printed out beneath the stack trace. The format of this information depends on the implementation, but the following example may be regarded as typical:

 Exception in thread "main" java.lang.Exception: Something happened
  at Foo.bar(Foo.java:10)
  at Foo.main(Foo.java:5)
  Suppressed: Resource$CloseFailException: Resource ID = 0
          at Resource.close(Resource.java:26)
          at Foo.bar(Foo.java:9)
          ... 1 more

Note that the "... n more" notation is used on suppressed exceptions just as it is used on causes. Unlike causes, suppressed exceptions are indented beyond their "containing exceptions."

An exception can have both a cause and one or more suppressed exceptions:

 Exception in thread "main" java.lang.Exception: Main block
  at Foo3.main(Foo3.java:7)
  Suppressed: Resource$CloseFailException: Resource ID = 2
          at Resource.close(Resource.java:26)
          at Foo3.main(Foo3.java:5)
  Suppressed: Resource$CloseFailException: Resource ID = 1
          at Resource.close(Resource.java:26)
          at Foo3.main(Foo3.java:5)
 Caused by: java.lang.Exception: I did it
  at Foo3.main(Foo3.java:8)

Likewise, a suppressed exception can have a cause:

 Exception in thread "main" java.lang.Exception: Main block
  at Foo4.main(Foo4.java:6)
  Suppressed: Resource2$CloseFailException: Resource ID = 1
          at Resource2.close(Resource2.java:20)
          at Foo4.main(Foo4.java:5)
  Caused by: java.lang.Exception: Rats, you caught me
          at Resource2$CloseFailException.<init>(Resource2.java:45)
          ... 2 more

java.lang.Object
↳	java.lang.Throwable

Throwable

Summary

Public constructors

Protected constructors

Public methods

Inherited methods

Public constructors

Throwable

Throwable

Throwable

Throwable

Protected constructors

Throwable

Public methods

addSuppressed

fillInStackTrace

getCause

getLocalizedMessage

getMessage

getStackTrace

getSuppressed

initCause

printStackTrace

printStackTrace

printStackTrace

setStackTrace

toString