B4J Code Snippet Fix for error: Cannot invoke "java.lang.ref.WeakReference.get()" because "wfe.senderFilter" is null

This error is a bit tricky. It happens when multiple resumable subs are waiting for events with the same name, some with sender filter set and others without.

This code reproduces this error:

'Call both subs in this order:
    t2
    t1


Private Sub t1
    Dim job As HttpJob
    job.Initialize("", Me)
    job.Download("https://www.b4x.com")
    Wait For (job) JobDone(job As HttpJob) 'with sender filter
    If job.Success Then
       Log(job.GetString)
    End If
    job.Release
End Sub

Private Sub t2
    Dim job As HttpJob
    job.Initialize("", Me)
    job.Download("https://www.b4x.com")
    Wait For JobDone(job As HttpJob) 'without sender filter
    If job.Success Then
       Log(job.GetString)
    End If
    job.Release
End Sub

This is a programming mistake as the only reliable way to intercept multiple events with the same name is based on the sender filter.
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