NullPointerException when writing to a file in Robocode

Question

I get NullPointerException while trying to write to a file:

        RobocodeFileWriter fileWriter=new RobocodeFileWriter("test.txt");
        for (int i = 0; i < state.countstates; i++)
            for (int j = 0; j < state.countactions; j++)
                fileWriter.write((int) table[i][j]);
        }

The exception:

java.lang.NullPointerException
    at net.sf.robocode.host.security.ThreadManager.createRobotFileStream(ThreadManager.java:136)
    at robocode.RobocodeFileOutputStream.<init>(RobocodeFileOutputStream.java:88)
    at robocode.RobocodeFileOutputStream.<init>(RobocodeFileOutputStream.java:69)
    at robocode.RobocodeFileWriter.<init>(RobocodeFileWriter.java:69)
    at QTable.saveData(QTable.java:79)
    at MyFirstRobot.saveToFile(MyFirstRobot.java:471)
    at MyFirstRobot.onDeath(MyFirstRobot.java:414)
    at robocode.DeathEvent.dispatch(DeathEvent.java:63)
    at robocode.Event$HiddenEventHelper.dispatch(Event.java:259)
    at net.sf.robocode.security.HiddenAccess.dispatch(HiddenAccess.java:191)
    at net.sf.robocode.host.events.EventManager.dispatch(EventManager.java:422)
    at net.sf.robocode.host.events.EventManager.processEvents(EventManager.java:376)
    at net.sf.robocode.host.proxies.BasicRobotProxy.executeImpl(BasicRobotProxy.java:412)
    at net.sf.robocode.host.proxies.BasicRobotProxy.execute(BasicRobotProxy.java:121)
    at robocode.AdvancedRobot.execute(AdvancedRobot.java:549)
    at MyFirstRobot.run(MyFirstRobot.java:68)
    at net.sf.robocode.host.proxies.HostingRobotProxy.callUserCode(HostingRobotProxy.java:274)
    at net.sf.robocode.host.proxies.HostingRobotProxy.run(HostingRobotProxy.java:221)
    at java.lang.Thread.run(Thread.java:695)

This exception occurs even if I disable the security manager by passing -DNOSECURITY=true My robocode version is 1.8.3.0 and doing the development on Mac. Any help is appreciated.

414: is a call to saveToFile 471: RobocodeFileWriter fileWriter=new RobocodeFileWriter("test.txt"); which is the first line in saveToFile method — Pooya, Nov 23 '13 at 06:45
Hmm, the file is not created. I tried the same code on both Windows and Mac, the same exception. Can it be a robocode bug? — Pooya, Nov 26 '13 at 22:36

Mina · Accepted Answer · 2013-12-03T04:32:52.903

1

I had the same problem, I added the package at the beginning and it worked. Did you add the package at the beginning? You can create a package to put all your codes in that package and then you need to include the package in each class in your code as well and it should work just fine.

edited Dec 03 '13 at 04:32

answered Nov 26 '13 at 22:56

Mina

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NullPointerException when writing to a file in Robocode

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