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NullPointerException
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 stack trace was not writable.
Summary
Inherited methods |
|
From class java.lang.Object Object | clone() Creates and returns a copy of this object. | boolean | equals(Object obj) Indicates whether some other object is "equal to" this one. | void | finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | final Class<?> | getClass() Returns the runtime class of this Object . | int | hashCode() Returns a hash code value for the 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. | String | toString() Returns a string representation of the object. | 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. | 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() Causes the current thread to wait until it is awakened, typically by being notified or interrupted. | |
Public constructors
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 | String : the detail message. |
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Last updated 2025-02-10 UTC.
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