The simple test at https://github.com/NeuronRobotics/nrjavaserial seems to hang.

Example Code From GitHub

The code at https://github.com/NeuronRobotics/nrjavaserial is

String port = "COM3";
int baudRate = 115200;
NRSerialPort serial = new NRSerialPort(port, baudRate);
serial.connect();

DataInputStream ins = new DataInputStream(serial.getInputStream());
DataOutputStream outs = new DataOutputStream(serial.getOutputStream());

byte b = ins.read();
outs.write(b);

serial.disconnect();

[$[Get Code]]

Example Code in PTII

The above code needs modifications to run, so we created $PTII/ptolemy/actor/lib/jjs/modules/serial/SerialTest.java:

public class SerialTest {
public static void main(String [] args) throws Exception {

String port = "/dev/tty.Bluetooth-Incoming-Port";

if (args.length != 1) {
System.err.println("Usage: java -classpath $PTII:${PTII}/lib/nrjavaserial-3.11.0.jar ptolemy.actor.lib.io.comm.SerialTest /dev/tty");
System.err.println("Below are the ports:");
// Enumerate the available ports.
Enumeration ports = CommPortIdentifier.getPortIdentifiers();
while (ports.hasMoreElements()) {
CommPortIdentifier identifier = (CommPortIdentifier) ports
.nextElement();
if (identifier.getPortType() == CommPortIdentifier.PORT_SERIAL) {
System.err.println(identifier.getName());
}
}
StringUtilities.exit(1);
} else {
port = args[0];
}

int baudRate = 9600;
NRSerialPort serialPort = new NRSerialPort(port, baudRate);
serialPort.connect();
System.out.println("Connected to " + serialPort);

DataInputStream inputStream = new DataInputStream(serialPort.getInputStream());
DataOutputStream outputStream = new DataOutputStream(serialPort.getOutputStream());

byte b = (byte)inputStream.read();
System.out.println("Read a byte: " + b);
outputStream.write(b);
System.out.println("Wrote a byte: " + b);

serialPort.disconnect();
System.out.println("Called serialPort.disconnect()");
}
}

[$[Get Code]]

Hangs Under Mac OS X

Under Mac OS X 10.11.1, which I run the program, it calls disconnect but does not end

bash-3.2$ java -classpath $PTII:${PTII}/lib/nrjavaserial-3.11.0.jar ptolemy.actor.lib.jjs.modules.serial.test.SerialTest /dev/cu.usbserial-DA01R74U
java -classpath $PTII:${PTII}/lib/nrjavaserial-3.11.0.jar ptolemy.actor.lib.jjs.modules.serial.test.SerialTest /dev/cu.usbserial-DA01R74U
Connected to gnu.io.NRSerialPort@28a418fc
Read a byte: -1
Wrote a byte: -1
Called serialPort.disconnect()

[$[Get Code]]

If I hit Control-Z, put it in the background and use kill -3 %3 to get a stack trace, I see that a thread is running:

^Z
[3]+ Stopped java -classpath $PTII:${PTII}/lib/nrjavaserial-3.11.0.jar ptolemy.actor.lib.jjs.modules.serial.test.SerialTest /dev/cu.usbserial-DA01R74U
bash-3.2$ bg
bg
[3]+ java -classpath $PTII:${PTII}/lib/nrjavaserial-3.11.0.jar ptolemy.actor.lib.jjs.modules.serial.test.SerialTest /dev/cu.usbserial-DA01R74U &
bash-3.2$ kill -3 %3
kill -3 %3
bash-3.2$ 2015-12-07 12:38:44
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.65-b01 mixed mode):

"DestroyJavaVM" #11 prio=5 os_prio=31 tid=0x00007fd36d044000 nid=0x1703 waiting on condition [0x0000000000000\
000]
java.lang.Thread.State: RUNNABLE

"Thread-0" #10 prio=5 os_prio=31 tid=0x00007fd36c04b000 nid=0x5b03 runnable [0x00007000015d5000]
java.lang.Thread.State: RUNNABLE
at gnu.io.RXTXPort.eventLoop(Native Method)
at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1611)

"Service Thread" #9 daemon prio=9 os_prio=31 tid=0x00007fd36d822000 nid=0x5203 runnable [0x0000000000000000]
java.lang.Thread.State: RUNNABLE

"C1 CompilerThread3" #8 daemon prio=9 os_prio=31 tid=0x00007fd36d821800 nid=0x5003 waiting on condition [0x00\
00000000000000]
java.lang.Thread.State: RUNNABLE

"C2 CompilerThread2" #7 daemon prio=9 os_prio=31 tid=0x00007fd36d001000 nid=0x4e03 waiting on condition [0x00\
00000000000000]
java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" #6 daemon prio=9 os_prio=31 tid=0x00007fd36c810000 nid=0x4c03 waiting on condition [0x00\
00000000000000]
java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #5 daemon prio=9 os_prio=31 tid=0x00007fd36c032800 nid=0x4a03 waiting on condition [0x00\
00000000000000]
java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 tid=0x00007fd36c01b800 nid=0x3e0f waiting on condition [0x000\
0000000000000]
java.lang.Thread.State: RUNNABLE
"Finalizer" #3 daemon prio=8 os_prio=31 tid=0x00007fd36c838000 nid=0x3803 in Object.wait() [0x0000700000d3a00\
0]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x000000076ab070b8> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
- locked <0x000000076ab070b8> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

"Reference Handler" #2 daemon prio=10 os_prio=31 tid=0x00007fd36c837000 nid=0x3603 in Object.wait() [0x000070\
0000c37000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x000000076ab06af8> (a java.lang.ref.Reference$Lock)
at java.lang.Object.wait(Object.java:502)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:157)
- locked <0x000000076ab06af8> (a java.lang.ref.Reference$Lock)

"VM Thread" os_prio=31 tid=0x00007fd36c834800 nid=0x3403 runnable

"GC task thread#0 (ParallelGC)" os_prio=31 tid=0x00007fd36c013800 nid=0x2403 runnable

"GC task thread#1 (ParallelGC)" os_prio=31 tid=0x00007fd36c014000 nid=0x2603 runnable

"GC task thread#2 (ParallelGC)" os_prio=31 tid=0x00007fd36c015000 nid=0x2803 runnable

"GC task thread#3 (ParallelGC)" os_prio=31 tid=0x00007fd36c802800 nid=0x2a03 runnable

"GC task thread#4 (ParallelGC)" os_prio=31 tid=0x00007fd36c803000 nid=0x2c03 runnable

"GC task thread#5 (ParallelGC)" os_prio=31 tid=0x00007fd36c803800 nid=0x2e03 runnable

"GC task thread#6 (ParallelGC)" os_prio=31 tid=0x00007fd36c804800 nid=0x3003 runnable

"GC task thread#7 (ParallelGC)" os_prio=31 tid=0x00007fd36c805000 nid=0x3203 runnable

"VM Periodic Task Thread" os_prio=31 tid=0x00007fd36d823000 nid=0x5403 waiting on condition

JNI global references: 6
Heap
PSYoungGen total 76288K, used 7864K [0x000000076ab00000, 0x0000000770000000, 0x00000007c0000000)
eden space 65536K, 12% used [0x000000076ab00000,0x000000076b2ae3a8,0x000000076eb00000)
from space 10752K, 0% used [0x000000076f580000,0x000000076f580000,0x0000000770000000)
to space 10752K, 0% used [0x000000076eb00000,0x000000076eb00000,0x000000076f580000)
ParOldGen total 175104K, used 0K [0x00000006c0000000, 0x00000006cab00000, 0x000000076ab00000)
object space 175104K, 0% used [0x00000006c0000000,0x00000006c0000000,0x00000006cab00000)
Metaspace used 3070K, capacity 4664K, committed 4864K, reserved 1056768K
class space used 337K, capacity 424K, committed 512K, reserved 1048576K

[$[Get Code]]

If, in the Mac OS X Activity Monitor, I select the java process (consuming 100% of my cpu) and select sample and search for RxTX, I get:

2683 JavaCalls::call_helper(JavaValue*, methodHandle*, JavaCallArguments*, Thread*) (in libjvm.dylib) + 1710 [0x1078eab02]
2683 ??? (in <unknown binary>) [0x1085897a7]
2683 ??? (in <unknown binary>) [0x108590c4d]
2683 ??? (in <unknown binary>) [0x10859e954]
2501 Java_gnu_io_RXTXPort_eventLoop (in libNRJavaSerial.jnilib) + 263 [0x124fa2317]
! 2427 __select (in libsystem_kernel.dylib) + 10 [0x7fff8d4b2222]
! 33 cerror (in libsystem_kernel.dylib) + 5,6,... [0x7fff8d4ad419,0x7fff8d4ad41a,...]
! 20 cerror (in libsystem_kernel.dylib) + 13 [0x7fff8d4ad421]
! : 15 _pthread_exit_if_canceled (in libsystem_pthread.dylib) + 0,37,... [0x7fff8b1e1c13,0x7fff8b1e1c38,...]
! : 5 _pthread_exit_if_canceled (in libsystem_kernel.dylib) + 0 [0x7fff8d49c398]
! 11 select$1050 (in libsystem_kernel.dylib) + 0,30 [0x7fff8d4af8c9,0x7fff8d4af8e7]
! 5 _pthread_exit_if_canceled (in libsystem_kernel.dylib) + 7,10 [0x7fff8d49c39f,0x7fff8d49c3a2]
! 5 cerror_nocancel (in libsystem_kernel.dylib) + 22 [0x7fff8d4ad405]
91 Java_gnu_io_RXTXPort_eventLoop (in libNRJavaSerial.jnilib) + 263,281,... [0x124fa2317,0x124fa2329,...]
46 Java_gnu_io_RXTXPort_eventLoop (in libNRJavaSerial.jnilib) + 336 [0x124fa2360]
! 46 initialise_event_info_struct (in libNRJavaSerial.jnilib) + 431,475,... [0x124fa202f,0x124fa205b,...]
18 __error (in libsystem_kernel.dylib) + 9,12 [0x7fff8d4ad3e0,0x7fff8d4ad3e3]
12 DYLD-STUB$$__error (in libNRJavaSerial.jnilib) + 0 [0x124fa3c94]
6 Java_gnu_io_RXTXPort_eventLoop (in libNRJavaSerial.jnilib) + 278 [0x124fa2326]
! 6 __error (in libsystem_kernel.dylib) + 23 [0x7fff8d4ad3ee]
4 Java_gnu_io_RXTXPort_eventLoop (in libNRJavaSerial.jnilib) + 297 [0x124fa2339]
! 4 __error (in libsystem_kernel.dylib) + 23,0 [0x7fff8d4ad3ee,0x7fff8d4ad3d7]
4 __select (in libsystem_kernel.dylib) + 12,0 [0x7fff8d4b2224,0x7fff8d4b2218]
1 DYLD-STUB$$select$1050 (in libNRJavaSerial.jnilib) + 0 [0x124fa3d66]

[$[Get Code]]

Source Code that is hanging.

We are using https://github.com/NeuronRobotics/nrjavaserial

The trace above:

2501 Java_gnu_io_RXTXPort_eventLoop (in libNRJavaSerial.jnilib) + 263 [0x124fa2317]
! 2427 __select (in libsystem_kernel.dylib) + 10 [0x7fff8d4b2222]
! 33 cerror (in libsystem_kernel.dylib) + 5,6,... [0x7fff8d4ad419,0x7fff8d4ad41a,...]
! 20 cerror (in libsystem_kernel.dylib) + 13 [0x7fff8d4ad421]

[$[Get Code]]

shows that the native code Java_gnu_io_RXTXPort_eventLoop() is looping

Interestingly, https://github.com/NeuronRobotics/nrjavaserial/tree/master/src/main/c/src shows a recent Mac OS X update:

   SerialImp.c 	Mark defunct ports as closing on OS X. 	17 days ago

Bingo! https://github.com/NeuronRobotics/nrjavaserial/tree/master/src/main/c/src says:

MrDOS Mark defunct ports as closing on OS X. �

Without this, CPU usage goes to 100% and stays there on OS X after calling CommPort.close().

The change to src/main/c/src/SerialImp.c from https://github.com/NeuronRobotics/nrjavaserial/commit/74c4f8c77caf51134d52445f6af16230ca14bd5e#diff-665a7a30164f5c2dc46596d456077413 is below:

@@ -4929,7 +4929,8 @@ JNIEXPORT void JNICALL RXTXPort(interruptEventLoop)(JNIEnv *env,
to close indefinetly.
*/
#if defined(__APPLE__)
- //If you continue on in OSX you get an invalid memory access error
+ index->closing = 1;
+ /* Continuing on OS X causes an invalid memory access. */
return;
#endif
if (index->drain_loop_running != 0) {

[$[Get Code]]

You can see that cerror() is getting called, so this probably has something to do with it.

On to nrjavaserial for building.

RxTxHanging

Example Code From GitHub

Example Code in PTII

Hangs Under Mac OS X

Source Code that is hanging.