#481 null.toString() kills interactions

[Dan Smith]

When I type this in the interactions pane:

null.toString()

it hangs until I reset.

I'm running version 20060407. This bug was not present in version
20060120.

[Mathias Ricken]

Logged In: YES
user_id=1075744

It seems any NullPointerException in the slave JVM does that.

> import java.io.*
> File f = null;
> f.exists()
Exception in thread "interpret thread: f.exists()"
java.lang.NullPointerException
at
edu.rice.cs.drjava.model.repl.InteractionsDocument.appendExceptionResult(InteractionsDocument.java:320)
at
edu.rice.cs.drjava.model.repl.InteractionsModel.replThrewException(InteractionsModel.java:489)
at
edu.rice.cs.drjava.model.repl.newjvm.MainJVM$ResultHandler.forExceptionResult(MainJVM.java:840)
at
edu.rice.cs.drjava.model.repl.newjvm.ExceptionResult.apply(ExceptionResult.java:88)
at
edu.rice.cs.drjava.model.repl.newjvm.MainJVM.interpretResult(MainJVM.java:249)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at
sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:294)
at sun.rmi.transport.Transport$1.run(Transport.java:153)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:149)
at
sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
at
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
at java.lang.Thread.run(Thread.java:595)
at
sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:247)
at
sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:223)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:126)
at
edu.rice.cs.drjava.model.repl.newjvm.MainJVM_Stub.interpretResult(Unknown
Source)
at
edu.rice.cs.drjava.model.repl.newjvm.InterpreterJVM$4.run(InterpreterJVM.java:295)

[Mathias Ricken]

Logged In: YES
user_id=1075744

My mistake. I tried to make an inconsequential exception
message about not being able to connect to 127.0.0.1 away
and was de-referencing a null pointer.

Fixed as of revision 3802.