Class NullPointerException

java.lang.NullPointerException

All Implemented Interfaces:: Serializable

public class NullPointerException extends RuntimeException

Thrown when an application attempts to use null in a case where an object is required. These include:

Calling the instance method of a null object.
Accessing or modifying the field of a null object.
Taking the length of null as if it were an array.
Accessing or modifying the slots of null as if it were an array.
Throwing null as if it were a Throwable value.

Applications should throw instances of this class to indicate other illegal uses of the null object. NullPointerException objects may be constructed by the virtual machine as if suppression were disabled and/or the stack trace was not writable.

Since:

1.0

See Also:

Constructor Summary

Constructor	Description
`NullPointerException()`	Constructs a `NullPointerException` with no detail message.
`NullPointerException(String s)`	Constructs a `NullPointerException` with the specified detail message.

Method Summary

Modifier and Type	Method	Description
`String`	`getMessage()`	Returns the detail message string of this throwable.

Methods declared in class Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Modifier and Type	Method	Description
`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.
`StackTraceElement[]`	`getStackTrace()`	Provides programmatic access to the stack trace information printed by `Throwable.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(PrintStream s)`	Prints this throwable and its backtrace to the specified print stream.
`void`	`printStackTrace(PrintWriter s)`	Prints this throwable and its backtrace to the specified print writer.
`void`	`setStackTrace(StackTraceElement[] stackTrace)`	Sets the stack trace elements that will be returned by `Throwable.getStackTrace()` and printed by `Throwable.printStackTrace()` and related methods.
`String`	`toString()`	Returns a short description of this throwable.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details

NullPointerException

public NullPointerException()

Constructs a NullPointerException with no detail message.

NullPointerException

public NullPointerException(String s)

Constructs a NullPointerException with the specified detail message.

Parameters:: s - the detail message.

Method Details

getMessage

public String getMessage()

Returns the detail message string of this throwable.

If a non-null message was supplied in a constructor it is returned. Otherwise, an implementation specific message or null is returned.

Overrides:: getMessage in class Throwable
Implementation Note:: If no explicit message was passed to the constructor, and as long as certain internal information is available, a verbose description of the null reference is returned. The internal information is not available in deserialized NullPointerExceptions.
Returns:: the detail message string, which may be null.

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