程序包 java.lang

类 NullPointerException

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

java.lang.NullPointerException

所有已实现的接口:

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 Throwable#Throwable(String, Throwable, boolean, boolean).

从以下版本开始:

JDK1.0

另请参阅:

序列化表格

构造器概要

构造器

构造器	说明
NullPointerException()	Constructs a NullPointerException with no detail message.
NullPointerException(String s)	Constructs a NullPointerException with the specified detail message.

方法概要

从类继承的方法 java.lang.Object

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

从类继承的方法 java.lang.Throwable

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

构造器详细资料

NullPointerException

public NullPointerException()

Constructs a NullPointerException with no detail message.

NullPointerException

public NullPointerException(String s)

Constructs a NullPointerException with the specified detail message.

参数:

s - the detail message.