NullPointerException

Class Overview

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.

Summary

[Expand] Inherited Methods
From class java.lang.Throwable synchronized 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(). synchronized Throwable initCause(Throwable cause) Initializes the cause of this throwable to the specified value. 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 printStackTrace() Prints this throwable and its backtrace to the standard error 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) 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() Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object. final void wait(long timeout, int nanos) Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed. final void wait(long timeout) Causes the current thread to wait until either another thread invokes the notify() method or the notifyAll() method for this object, or a specified amount of time has elapsed.