B4J Question Error: Only occurs when in debug and no breakpoints and in release version

[rgarnett1955]

Hi,

Using B4J 9.5 (64 Bit)

I am getting an error:

Peek (ClassCastException) java.lang.ClassCastException: class [F cannot be cast to class [I ([F and [I are in module java.base of loader 'bootstrap')

I am getting this error when I compile for release or I am in debug with NO break points.

As soon as I add one break point even though it is not being hit the error does not occur:

No Break Point or release mode

With Break Point:

The function is contained within a standard class and is being called from a timer.

I have seen this error in other situations.

The function where the error is occurring is:

'============================================================================================
' Examine the data at a place relative to the tail and return the value in data
' Data is not removed from buffer. If look ahead counter <= 0 or > current size
' then all entries are returned
public Sub cbuf_peek(look_ahead_counter As Int) As List
    Dim pos As Int
    Dim outList As List
    outList.Initialize
  
    Dim data(noFields) As Int
      
    'We can't look beyond the current buffer size
    If  cbuf_empty Then
        Return outList
    End If

    If look_ahead_counter > cbuf_size Or look_ahead_counter < 0 Then
        look_ahead_counter = cbuf_size
    End If

    pos = tail
    For k = 0 To look_ahead_counter
        pos = advance_headtail_value(pos)
    Next
  
    #IF MIN_LOGGING_ON Or LOGGING_ON
    Log(" Peek: Pos - 1  = " & (pos - 1) & " Cbuf Size = " &  cbuf_size & "  List Size = " & buffer.Size)
    #End If
  
    Try 
        data =     buffer.Get(pos - 1)
        outList.Add(data)
    Catch
        Log("Peek " & LastException)
    End Try 
    Return outList
End Sub

The full error stack without the try statement is:

Waiting for debugger to connect...
Program started.
IPC: My ip is: 192.168.1.114
mcuClient Line 693(SQLiteException) org.sqlite.SQLiteException: [SQLITE_ERROR] SQL error or missing database (table cmdList already exists)
Cmd Timer - Tick .......
CMD_NULL Processed OK Nt =   Time 14-44-32
Cmd Timer - Tick .......
CMD_NULL Processed OK Nt =   Time 14-44-37
Cmd Timer - Tick .......
CMD_NULL Processed OK Nt =   Time 14-44-43
processPersistantCommands = True
Get temp control Vars
Packet Header No Recs = 20  No Recs Max Per Packet = 71
 Peek: Pos - 1  = 19 Cbuf Size = 20  List Size = 20
Error occurred on line: 399 (circBuffVars)
java.lang.ClassCastException: class [F cannot be cast to class [I ([F and [I are in module java.base of loader 'bootstrap')
    at b4j.shortBridgeMinLogging.circbuffvars._cbuf_peek(circbuffvars.java:218)
    at b4j.shortBridgeMinLogging.mcuproccmd._logtuningvarsfromcircbuffer(mcuproccmd.java:724)
    at b4j.shortBridgeMinLogging.mcuproccmd$ResumableSub_processTempTuningVars.resume(mcuproccmd.java:2022)
    at b4j.shortBridgeMinLogging.mcuproccmd._processtemptuningvars(mcuproccmd.java:1880)
    at b4j.shortBridgeMinLogging.mcuproccmd$ResumableSub_mcu_retData.resume(mcuproccmd.java:475)
    at b4j.shortBridgeMinLogging.mcuproccmd._mcu_retdata(mcuproccmd.java:202)
    at b4j.shortBridgeMinLogging.mcuclient._tcpstream_newdata(mcuclient.java:3312)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:629)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:234)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:167)
    at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:111)
    at anywheresoftware.b4a.shell.ShellBA.raiseEvent2(ShellBA.java:98)
    at anywheresoftware.b4a.BA$2.run(BA.java:250)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
    at java.base/java.lang.Thread.run(Thread.java:834)

I tried putting a sleep() in the code irrationally thinking that might help, bit it didn't.

I don't remember seeing this happen in older versions of B4j, but I can't be sure about this.

The problem is that as soon as I try to debug it with a break-point the error does not occur.

Does anyone know what is happening?


Regards
Rob

PS Additional:

If I make the code more efficient:

    Try   
        outList.Add(buffer.Get(pos - 1))
    Catch
        Log("Peek " & LastException)
    End Try

The problem goes away.

Strange

 

[Erel]

The debugger has two execution pipelines. In some edge cases there could be behavioral differences.

The error happens because you are treating an array of floats as an array of ints.

 

[rgarnett1955]

Thanks Erel,

But my code was a bit smelly. When I fixed it the problem went awy.

Best Regards
Rob