ExceptionInInitializerError thrown when creating a new TypefaceSpan object

ExceptionInInitializerError thrown when creating a new TypefaceSpan object

I'm trying to change my ActionBar font in an android application.
Everything works just fine while running my code on a 4.3 device but when
I'm trying to run it on a 2.3.3 device my app crashes.
This is the function that I'm using to change the font:
SpannableString s = new SpannableString("MyActivity");
s.setSpan(new TypefaceSpan(this, "myFont"), 0, s.length(),
Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
// Update the action bar title with the TypefaceSpan instance
ActionBar actionBar = getSupportActionBar();
actionBar.setTitle(s);
My app crashes thanks to the new TypefaceSpan line.
08-31 19:00:21.359: E/AndroidRuntime(3874): FATAL EXCEPTION: main
08-31 19:00:21.359: E/AndroidRuntime(3874):
java.lang.ExceptionInInitializerError
08-31 19:00:21.359: E/AndroidRuntime(3874): at
com.blabla.myapp.MainActivity.changeActionBarFont(MainActivity.java:41)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
com.blabla.myapp.MainActivity.setupGUIandListeners(MainActivity.java:27)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
com.blabla.myapp.MainActivity.onCreate(MainActivity.java:23)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1675)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.app.ActivityThread.access$1500(ActivityThread.java:121)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:943)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.os.Handler.dispatchMessage(Handler.java:99)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.os.Looper.loop(Looper.java:130)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
android.app.ActivityThread.main(ActivityThread.java:3768)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
java.lang.reflect.Method.invokeNative(Native Method)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
java.lang.reflect.Method.invoke(Method.java:507)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:878)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
08-31 19:00:21.359: E/AndroidRuntime(3874): at
dalvik.system.NativeStart.main(Native Method)
08-31 19:00:21.359: E/AndroidRuntime(3874): Caused by:
java.lang.NoClassDefFoundError: android.util.LruCache
08-31 19:00:21.359: E/AndroidRuntime(3874): at
com.blabla.myapp.TypefaceSpan.<clinit>(TypefaceSpan.java:34)
08-31 19:00:21.359: E/AndroidRuntime(3874): ... 16 more
08-31 19:00:21.369: E/(186): Dumpstate > /data/log/dumpstate_app_error
I'm setting the font in my onCreate function.
Any help / ideas ?
Thanks in advance