How to solve the java.lang.NullPointerException?

Core Library Questions

mechart

How to solve the java.lang.NullPointerException?

in Core Library Questions • 8 months ago

When I run a program with serialEvent, the java.lang.NullPointerException occurs, but not everytime.

The messages processing given are as follows:

Stable Library

=========================================

Native lib Version = RXTX-2.1-7

Java lib Version = RXTX-2.1-7

java.lang.NullPointerException

at processing.mode.java.runner.Runner.findException(Runner.java:682)

at processing.mode.java.runner.Runner.reportException(Runner.java:627)

at processing.mode.java.runner.Runner.exception(Runner.java:570)

at processing.mode.java.runner.EventThread.exceptionEvent(EventThread.java:367)

at processing.mode.java.runner.EventThread.handleEvent(EventThread.java:255)

at processing.mode.java.runner.EventThread.run(EventThread.java:89)

Exception in thread "Thread-6" java.lang.NullPointerException

at processing.serial.Serial.serialEvent(Unknown Source)

at gnu.io.RXTXPort.sendEvent(RXTXPort.java:732)

at gnu.io.RXTXPort.eventLoop(Native Method)

at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1575)

Any help is greatly thanks!

Replies(1)

akseidel

Re: How to solve the java.lang.NullPointerException?

7 months ago

Have you placed printlns in your code to narrow down exactly where this occurs? It almost looks like the error occurs sometime after a serialEvent where you might have some condition your code caused that results in a bogus value. I currently have a similar error message that happens because I cannot figure out how to recover from the USB being temporarily unplugged while the program is running.

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