Android and db4o.Can Create db on emulator but not on real device

Question

I'm writing my first Android app. And i wanted to use db4o, just because i've never used it before. I just try to open/create the database.Everything works fine when i running this on a virtual device. But when im going for my real device i always get the exceptions written below:

  ...ActivityClass{
private void deleteDB() {
    DatabaseHandler db = new DatabaseHandler();
    db.open(getString(R.string.database));
    db.deleteAll();
    db.close();
}
}....
The R.string.database = /data/data/de.workingtimemanager.urb/databases/WTM.db
my package = de.workingtimemanager.urb

public class DatabaseHandler {
    private ObjectContainer database;
public DatabaseHandler() {}

public void open(String name) {
    EmbeddedConfiguration conf = Db4oEmbedded.newConfiguration();
    conf.common().objectClass(User.class).cascadeOnDelete(true);
    conf.common().objectClass(User.class).cascadeOnUpdate(true);
    conf.common().objectClass(Project.class).cascadeOnDelete(true);
    conf.common().objectClass(Project.class).cascadeOnUpdate(true);
    database = Db4oEmbedded.openFile(conf, name);
    }
}
11-01 13:38:36.385: ERROR/AndroidRuntime(4774): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.workingtimemanager.urb/de.workingtimemanager.urb.WorkingTimeManagerActivity}: com.db4o.ext.Db4oIOException: /data/data/de.workingtimemanager.urb/databases/WTM.db (No such file or directory)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.os.Handler.dispatchMessage(Handler.java:99)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.os.Looper.loop(Looper.java:123)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.app.ActivityThread.main(ActivityThread.java:3691)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at java.lang.reflect.Method.invokeNative(Native Method)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at java.lang.reflect.Method.invoke(Method.java:507)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at dalvik.system.NativeStart.main(Native Method)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774): Caused by: com.db4o.ext.Db4oIOException: /data/data/de.workingtimemanager.urb/databases/WTM.db (No such file or directory)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.io.RandomAccessFileFactory.newRandomAccessFile(RandomAccessFileFactory.java:26)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.io.FileStorage$FileBin.<init>(FileStorage.java:43)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.io.FileStorage.open(FileStorage.java:22)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.io.StorageDecorator.open(StorageDecorator.java:27)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.io.CachingStorage.open(CachingStorage.java:52)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.internal.IoAdaptedObjectContainer.openImpl(IoAdaptedObjectContainer.java:57)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.internal.ObjectContainerBase$1.run(ObjectContainerBase.java:140)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.foundation.DynamicVariable.with(DynamicVariable.java:54)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.foundation.Environments.runWith(Environments.java:28)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.internal.ObjectContainerBase.withEnvironment(ObjectContainerBase.java:161)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.internal.ObjectContainerBase.open(ObjectContainerBase.java:131)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.internal.IoAdaptedObjectContainer.<init>(IoAdaptedObjectContainer.java:35)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.internal.ObjectContainerFactory.openObjectContainer(ObjectContainerFactory.java:18)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.Db4oEmbedded.openFile(Db4oEmbedded.java:65)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at de.workingtimemanager.urb.db.DatabaseHandler.open(DatabaseHandler.java:33)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at de.workingtimemanager.urb.WorkingTimeManagerActivity.deleteDB(WorkingTimeManagerActivity.java:22)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at de.workingtimemanager.urb.WorkingTimeManagerActivity.onCreate(WorkingTimeManagerActivity.java:15)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     ... 11 more

11-01 13:38:36.385: ERROR/AndroidRuntime(4774): Caused by: java.io.FileNotFoundException: /data/data/de.workingtimemanager.urb/databases/WTM.db (No such file or directory)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at org.apache.harmony.luni.platform.OSFileSystem.open(Native Method)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:232)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at java.io.RandomAccessFile.<init>(RandomAccessFile.java:132)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at java.io.RandomAccessFile.<init>(RandomAccessFile.java:173)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     at com.db4o.io.RandomAccessFileFactory.newRandomAccessFile(RandomAccessFileFactory.java:19)

11-01 13:38:36.385: ERROR/AndroidRuntime(4774):     ... 29 more

Answer 1

Check whether db4o jar file exists in library. If Library also has AndroidDependency, it should also contain db4o jar file. If it doesn't exist, ClassNotFoundError might occur.

Inorder to fix this issue, u can either remove AndroidDependency from the project library or add db4o jar file to the AndroidDependency

Answer 2

Did you check that you can create and write a file at that location? Usually you use the data directory for this to be sure that you have the proper rights:

    String filePath = this.getFilesDir() + "/android.db4o";
    final EmbeddedConfiguration config = Db4oEmbedded.newConfiguration();
    config.common().add(new AndroidSupport());
    ObjectContainer db = Db4oEmbedded.openFile(config,filePath);