NullPointerException from example - fresh windows install processing 4.3

[jmej]

I have run this example code on many installs of 4.3 using theMidiBus library from the package manager but on this particular system (windows 11 pro) I can't get the exmaple to run without a NullPointerException with no further information.

I tried downloading the latest library release manually but had the same problem.

[jmej]

the workaround mentioned here seems to work...

[AndresMartinM]

hi ✌️ i tried the examples, and apparently i fixed that problem in particular changing the parent of the MidiBus from 'this' to 'new java.lang.Object()'.
myBus = new MidiBus(new java.lang.Object(), -1, 3);
i'm using the processing library manager version of themidibus. i still have some other issues, but the nullpointerexception disappears

[fukuchi]

There are other workarounds as shown below.

// myBus = new MidiBus(this, input, output);
myBus = new MidiBus();
myBus.registerParent(this);
myBus.addInput(input);
myBus.addOutput(output);

[vicente95650]

I had given up trying to find workaround for my NullPointerException problem when using Processing 4, and had gone back to Processing 3 until I found this simple workaround by fukuchi which works with Processing 4.3!
Replacing the file themidibus.jar did not fix my NullPointerException problem but using fukuchi's workaround did.
I am on macOS Sonoma on a mac studio with an apple processor.

In fact even the following simpler workaround works:
// myBus = new MidiBus(this, input, output);
myBus = new MidiBus(null, input, output); // don't directly specify this sketch as the parent
registerParent(this); // specify the sketch as parent

In fact the single-line workaround suggested by AndresMartinM also works:
myBus = new MidiBus(new java.lang.Object(), input, output); // a new instance of java.lang.Object, instead of this sketch, is the parent.

It appears that the essence of this workaround is to not directly specify this sketch as the parent when initializing the MidiBus object!

[donausoft]

This worked only partial for me:
myBus = new MidiBus(new java.lang.Object());

After using this or other similar lines, MidiBus worked only for output.
Not for input.

The solution for me was:

MidiReceiver receiver = new MidiReceiver();
myBus = new MidiBus(receiver);

public class MidiReceiver { 
    void noteOn(int channel, int pitch, int velocity) { /* ... */ }
    /* ... */
}

As mentioned here:
#28 (comment)