Message378

When using a Java Collection class (such as ArrayList),
Jython will allow you to take [0] of an empty
collection. Unfortunately, [0] is a null or something,
so it has very strange behavior as shown below:

>>> from java.util import ArrayList
import: 'ArrayList' as java class
>>> al = ArrayList()
>>> foo = al[0]
>>> foo
Traceback (innermost last):
File "<console>", line 1, in ?
NameError: foo
>>> print al[0]
Traceback (innermost last):
File "<console>", line 1, in ?
java.lang.NullPointerException
at org.python.core.StdoutWrapper.print(StdoutWrapper.java)
at
org.python.core.StdoutWrapper.println(StdoutWrapper.java)
at org.python.core.Py.println(Py.java)
at org.python.pycode._pyx5.f$0(<console>:1)
at org.python.pycode._pyx5.call_function(<console>)
at org.python.core.PyTableCode.call(PyTableCode.java)
at org.python.core.PyCode.call(PyCode.java)
at org.python.core.Py.runCode(Py.java)
at org.python.core.Py.exec(Py.java)
at
org.python.util.PythonInterpreter.exec(PythonInterpreter.java)
at
org.python.util.InteractiveInterpreter.runcode(InteractiveInterpreter
.java)
at
org.python.util.InteractiveInterpreter.runsource(InteractiveInterpret
er.java)
at
org.python.util.InteractiveInterpreter.runsource(InteractiveInterpret
er.java)
at
org.python.util.InteractiveConsole.push(InteractiveConsole.java)
at
org.python.util.InteractiveConsole.interact(InteractiveConsole.java)
at org.python.util.jython.main(jython.java)

java.lang.NullPointerException:
java.lang.NullPointerException