NullPointerException

Class Overview

This runtime exception is thrown when an attempt is made to access a field or method of an instance or an element of an array when there is no instance or array to use (i.e. the pointer is null).

Summary

[Expand] Inherited Methods
From class java.lang.Throwable Throwable fillInStackTrace() Records in the receiver a stack trace from the point where this message was sent. Throwable getCause() Returns the cause of this Throwable, or null if there is no cause. String getLocalizedMessage() Returns the extra information message which was provided when the throwable was created. String getMessage() Returns the extra information message which was provided when the throwable was created. StackTraceElement[] getStackTrace() Returns an array of StackTraceElement. Throwable initCause(Throwable throwable) Initialize the cause of the receiver. void printStackTrace() Outputs a printable representation of the receiver's stack trace on the System.err stream. void printStackTrace(PrintWriter err) Outputs a printable representation of the receiver's stack trace on the PrintWriter specified by the argument. void printStackTrace(PrintStream err) Outputs a printable representation of the receiver's stack trace on the PrintStream specified by the argument. void setStackTrace(StackTraceElement[] trace) Sets the array of StackTraceElements. String toString() Returns a string containing a concise, human-readable description of the receiver.
From class java.lang.Object Object clone() Returns a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver. boolean equals(Object o) Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison. void finalize() Called by the virtual machine when there are no longer any (non-weak) references to the receiver. final Class<? extends Object> getClass() Returns the unique instance of java.lang.Class which represents the class of the receiver. int hashCode() Returns an integer hash code for the receiver. final void notify() Causes one thread which is wait ing on the receiver to be made ready to run. final void notifyAll() Causes all threads which are wait ing on the receiver to be made ready to run. String toString() Returns a string containing a concise, human-readable description of the receiver. final void wait(long time, int frac) Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout. final void wait(long time) Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout. final void wait() Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).